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Trimble Outdoors 45005-00-ENG User's Manual

1. ime 2000 Port B Tx Port B Tx Port B Rx Port B Rx Port A Tx Port A Tx Event In Port A Rx Event In Port A Rx PPS Out PPS Out DC Power In Ground Acutime 2000 Block Diagram RS 422 Version Acutime 2000 Synchronization Kit User Guide Theory of Operation F F 12 Acutime 2000 Synchronization Kit User Guide Glossary This section defines technical terms and abbreviations used in this manual It includes terms from the field of GPS technology 2 D Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed 2 D GPS mode A procedure of determining a 2 D position using signals received from the best or only three available GPS satellites Altitude is assumed to be known and constant A 2 D position solution will only be determined if signals from three or more satellites are available 3 D Three Dimensional A 3 D position is defined as latitude longitude and altitude 3 D GPS mode A procedure of determining a 3 D position using signals received from the best or only four available GPS satellites A 3 D position solution will only be determined if signals from four or more satellites are available almanac A reduced precision subset of the ephemeris parameters Used by the receiver to compute the elevation angle azimuth angle and estimated Doppler of the satellites Each satellite broadcasts the almanac
2. 6378135 000 0 00669431777827 FWGS 72 6378137 000 0 00669438002290 NAD 83 6378137 000 0 00669437999014 NAD 02 6378137 000 0 00669437999014 Mexican 6378137 000 0 00669437999014 Hawaiian 6378137 000 0 00669437999014 Astronomic 6378137 000 0 00669437999014 FU S Navy 6378388 000 0 00672267002233 European 6378160 000 0 00669454185459 Australian 1984 6378249 145 0 00680351128285 Adindan Mean 6378249 145 0 00680351128285 Adindan Ethiopia 6378249 145 0 00680351128285 Adindan Mali 6378249 145 0 00680351128285 Adindan Senegal 6378249 145 0 00680351128285 Adindan Sudan 6378245 000 0 00669342162297 Afgooye Somalia 6378388 000 0 00672267002233 Ain El Abd Bahrain 6378160 000 0 00669454185459 Anna 1 Astr 1965 6378249 145 0 00680351128285 Arc 1950 Mean A 126 6378249 145 0 00680351128285 Arc 1950 Botswana Acutime 2000 Synchronization Kit User Guide Table A 101 Datums Continued A axis 6378249 145 Trimble Standard Interface Protocol Eccentricity 0 00680351128285 Description Arc 1950 Lesotho 6378249 145 0 00680351128285 Arc 1950 Malawi 6378249 145 0 00680351128285 Arc 1950 Swaziland 6378249 145 0 006
3. Observatorio 1966 Acutime 2000 Synchronization Kit User Guide A Table A 101 Datums Continued A axis 6378200 0 Eccentricity 0 00669342162297 Trimble Standard Interface Protocol Description Old Egyptian 1907 6378206 400 0 00676865799761 Old Hawaiian mean 6378206 400 0 00676865799761 Old Hawaiian Hawaii 6378206 400 0 00676865799761 Old Hawaiian 6378206 400 0 00676865799761 Old Hawaiian 6378206 400 0 00676865799761 Old Hawaiian 6378249 15 0 00680351128285 Oman 6377563 4 0 00667053999999 Ord Sur Brit 36 Mean 6377563 4 0 00667053999999 OSB England 6377563 4 0 00667053999999 OSB Isle of Man 6377563 4 0 00667053999999 OSB Scotland Shetland 6377563 4 0 00667053999999 OSB Wales 6378388 0 0 00672267002233 Pico De Las Nieves 6378388 0 0 00672267002233 Pitcairn Astro 1967 6378388 0 0 00672267002233 Prov So Chilean1963 6378388 0 0 00672267002233 Prov S American 1956 Mean 6378388 0 0 00672267002233 Prov S American 1956 Bolivia 6378388 0 0 00672267002233 Prov S American 1956 N Chile 6378388 0 0 00672267002233 Prov S American 1956 S Chile 6378388 0 Acutime 2000 Synchronization Kit User Guide 0 00672267002233
4. if rpt gt status HAVE switch this_byte case DLE break _DLE Read bytes until serial buffer is empty or a complete report has nd of report is signified by DLE ETX yl DLE stuffed so it s a data byte Acutime 2000 Synchronization Kit User Guide Trimble Standard Interface Protocol case ETX End of message rpt gt status COMPLETE return TRUE default If previous message has ended this is new ID code reset_rptbuf rpt if not this is an error rpt gt code this _byte return FALSE else if this_byte DLE DLE byte without previous DLE stuffing must be stuffing rpt gt status HAVE_DLE continue normal byte add to report rpt gt status INCOMPLETE rpt gt buf rpt gt cnt this_byte rpt gt cnt if rpt gt cnt gt MAX_RPTBUF reset_rptbuf rpt return FALSE Prepare for receipt of new report void reset_rptbuf TSIPPKT rpt rpt gt cnt 0 rpt gt code ETX rpt gt status INCOMPLETE Acutime 2000 Synchronization Kit User Guide A 137 Trimble Standard Interface Protocol A A 138 Acutime 2000 Synchronization Kit User Guide B Timing Receiver Monitor The Timing Receiver Monitor program disk is included with the Acutime 2000 Synchronization Kit The latest version of the pro
5. The rate at which bits are transmitted over a communication path Normally expressed in bits per second bps A set of contiguous bits that make up a discrete item of information A byte usually consists of a series of 8 bits and represents one character Acutime 2000 Synchronization Kit User Guide C A code carrier channel chip chip rate configuration data bits datum DCE default setting Glossary The Coarse Acquisition code This is the civilian code made available by the Department of Defense It is subject to selective availability SA Users can reduce the effects of SA by using differential GPS The radio signal on which information is carried The carrier can be sensed to determine the presence of a signal Either a single frequency or a pair of radio frequencies used as a communication path The length of time to transmit either a zero or a one ina binary pulse code Number of chips per second e g C A code 1 023 MHz A set of conditions or parameters that define the structure of an item In regards to Placer a configuration defines the GPS processing and characteristics of the RS 232 interface ports The term configuration can also define the hardware components that comprise a subsystem or system The bits in a byte of data which carry the actual information A mathematical model of the earth Many local datums model the earth for a small region for example Tokyo datum Alask
6. This mode can be used to confirm communication between the Acutime NTP Reference Clock and NTP without relying on the event trigger connection The event trigger feature may not be functional on all systems If the Acutime NTP driver detects a problem using the event trigger it reverts to event disabled mode bX Note Running NTP without the Event Trigger degrades performance to the level of a conventional serial NTP reference clock E 12 Acutime 2000 Synchronization Kit User Guide E NTP Diagnostics and Debugging To configure NTP to disable output you need to edit the configuration file and add the line fudge 127 127 127 x flag2 1 El ntp conf Notepad Mil x File Edit Search Help Event Disabled Configuration File for Palisade NTP Trimble Palisade Smart Antenna GPS server 127 127 29 1 disable events on this device fudge 127 127 29 1 flag2 1 Then run NTP in debug mode ntpd d to observe Palisade_receive events Acutime 2000 Synchronization Kit User Guide E 13 NTP Diagnostics and Debugging E Receive events generated without event polling should be reported as poll events of this format Palisade_poll unit x polling synchronous packet E xterm olx lucky_first ntpd d create_sockets 123 bind fd 5 family 2 port 123 addr 0 0 0 0 flags 1 bind fd 6 family 2 port 123 addr 127 0 0 1 flags 0 bind fd 7 family 2 port 123 addr 155 63 33 57 flags 1 init_iot maxactivefd 7
7. 5 4 5 2 3 PPS Output Options o o a 5 6 5 2 4 PPS Quantization Error 2 2 ee ee 5 7 5 2 5 External EventInput 5 9 5 2 6 Cable Delay Compensation 5 9 5 3 Serial Data Communication o 5 10 5 3 1 POB A a do naa 5 10 5 3 2 Port A Timing 5 10 JA GPS Timing teo ir do de 5 12 5 4 1 Timing Operation o e e 5 13 Acutime 2000 Synchronization Kit User Guide Contents 5 5 Using the Acutime 2000 in Mobile Applications 5 15 5 6 Customizing Acutime 2000 Operations 5 16 6 NTP Software Installation and Configuration 6 1 Network Time Protocol o 6 1 6 1 1 NTP Time Servers o o 6 2 6 2 Software Sources and Compatibility 6 3 6 2 1 Installation Support o a 6 4 6 3 Pre Installation Check List o 6 4 6 3 1 GPS Preparation o o e 6 5 6 3 2 Host System Preparation o 6 6 6 3 3 Operating System Specific Information 6 7 6 4 Time Transfer Cable Connection o o 6 8 6 4 1 Optional Connections o o o 6 9 6 5 NTP Software Installation o 6 10 6 5 1 NTP Configuration File 6 11 6 5 2 Acutime Configuration o o 6 12 6 5 3 Network Server Selection 6 13 6 5 4 Additional
8. A 7 Table A 7 Receiver Warm Start Commands A 7 Table A 8 Background Packets o o A 8 Table A 9 Automatic position and Velocity Reports A 9 Table A 10 Low Latency Timing Packets A 10 Acutime 2000 Synchronization Kit User Guide xiii List of Tables Table A 11 Table A 12 Table A 13 Table A 14 Table A 15 Table A 16 Table A 17 Table A 18 Table A 19 Table A 20 Table A 21 Table A 22 Table A 23 Table A 24 Table A 25 Table A 26 Table A 27 Table A 28 Table A 29 Table A 30 Table A 31 Table A 32 Table A 33 Table A 34 Table A 35 Table A 36 Table A 37 Table A 38 Table A 39 Table A 40 xiv Satellite Data Packets o aaa A 11 Customizing Receiver Operations A 12 Advanced Packets ooa aa a A 13 Command Packets Sent to the Receiver A 14 Report Packets Sent by GPS Receiver to User A 16 Command Packet 1D Clear Oscillator Offset A 20 Command Packet 1D Set Oscillator Offset A 20 Command Packet1E o 020084 A 21 Command Packet23 o o A 22 Command Packet2B oo A 26 Command Packet2E o o A 27 Command Packet35 ooo A 31 Command Packet38 oo EA A 36 Command Packet39 o ooo A 37 Command Packet 3A o o o A 38 Command Packet3BB o o
9. A 90 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x8E 4A Command Packet 8E 4A Set Request PPS Characteristics Using this packet you can query and control the receiver s PPS characteristics The receiver responds to a query or control command with packet 8F 4A The packet contains 16 bytes in the following order Table A 75 Command Packet 8E 4A Meaning Sub packet ID BYTE Always 0x4A PPS Driver Switch BYTE O off 1 on default Time Base BYTE 0 GPS 1 UTC default PPS Polarity BYTE 0 positive default 1 negative PPS Offset or Cable Delay DOUBLE seconds default 0 0 Bias Uncertainty Threshold FLOAT meters default 300 To request 8F 4A send a two byte 8E 4A packet without any parameters To update parameters send the entire 16 byte message Acutime 2000 Synchronization Kit User Guide A 91 Trimble Standard Interface Protocol A The default setting for byte 3 is positive Bytes 4 to 11 define the PPS cable delay offset The default offset is 0 which corresponds to a 100 foot 30 meter cable These bytes allow the application to adjust the cable delay offset for longer or shorter cable lengths Use a cable delay of 1 25 ns foot to adjust PPS offset for cable lengths different than 100 feet For a longer cable a negative value should be used to advance the PPS ACE UTC GPS estimates the bias uncertainty as part of a PPS validity mon
10. Local Clock Offset This field carries the offset of the local clock relative to UTC or GPS as reported by the GPS receiver in nanoseconds Positive values indicate that the ACE UTC GPS s local clock is late relative to GPS or UTC Also known as bias Oscillator Offset This field carries the frequency offset of the local clock relative to UTC or GPS as reported by the GPS receiver in ppb parts per billion Positive values indicate that the ACE UTC GPS s local clock is running slow relative to GPS or UTC Also known as bias rate Latitude This field carries the latitude of the position being shown The units are in radians and vary from 7 2 to 7 2 Negative values represent southern latitudes Positive values represent northern latitudes Longitude This field carries the longitude of the position being shown The units are in radians and vary from n to m Negative values represent western longitudes Positive values represent eastern longitudes Altitude This field carries the altitude of the position being shown The units are in meters according to the current datum PPS Quantization Error This field identifies the PPS quantization error in nanoseconds PPS Output Status This field identifies the status of the PPS output A 120 Acutime 2000 Synchronization Kit User Guide Trimble Standard Interface Protocol The table below identifies the fields associated with packet 8F AC Table
11. Request Send 0x8F AB immediately type Send 0x8F AB on time next second Send 0x8F AB and 0x8F AC on time next second A 100 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x8E AC Command Packet 8E AC Request Supplemental Timing Packet This command packet can be used to request the supplemental timing packet 8F AC To receive report packet 8F AC once per second use command 8E AS to enable the automatic output The Request Type item determines how the ACE UTC GPS will reply to this command Request Type 0 The most current supplemental timing values will be sent in report packet 8F AC immediately e Request Type 1 The response is not sent immediately Instead report packet 8F AC is sent within 300ms after the next PPS output This is the same time that the packet would be automatically sent if enabled Request Type 2 Same as type 1 except that both report packets 8F AB and 8F AC are sent after the next PPS output Table A 84 Command Packet 8E AC Meaning Subcode Request Send 0x8F AC immediately type Send 0x8F AC on time next second Send 0x8F AB and 0x8F AC on time next second Acutime 2000 Synchronization Kit User Guide A 101 Trimble Standard Interface Protocol A 0x8E AD Command Packet 8E AD Acutime 2000 only Request or Configure Super Packet Output If the 8E AD byte sequence is sent with no data the receiver will generate an
12. A 2 3 Secondary Port Features Ace UTC Due to the number of available I O pins the Ace UTC does not generate output on its secondary port The input port may be configured as shown in the table below Table A 4 Secondary Port Features Ace UTC Port Designator Input Default Output Port 2 TSIP RTCM TSIP N A Event Input The Ace UTC and Acutime 2000 receivers are capable of time stamping external events with high precision Events are triggered by an input pulse and can be reported by either or both of two super packets The output of the event packets can be configured using packet 8E AS The data in both packets allows constructing a unique 4 dimensional coordinate identifying each event Event Reporting Table A 5 Event Packets Super Packet Length Description 8F 0B 74 Comprehensive time with LLA position 8F AD 22 Primary UTC time with leap information The receivers can output the event reports on any available TSIP port A 3 Packets Output at Power Up The following table lists the messages output by the receiver at power up After completing its self diagnostics the receiver automatically outputs a series of packets that indicate the initial Acutime 2000 Synchronization Kit User Guide Table A 6 Output ID Trimble Standard Interface Protocol operating condition of the receiver Messages are output in the following order Upon output of packe
13. Acutime 2000 Installation 3 3 4 Connecting the Host System The final step if applicable is the installation of the connector on the host end of the cable The connector installation instructions depend on the type of connector required by the host system For information on pin outs see Chapter 4 Acutime 2000 Connections 3 6 Acutime 2000 Synchronization Kit User Guide A Acutime 2000 Connections This chapter provides instructions on connecting the Acutime 2000 to the host system and power source Acutime 2000 Synchronization Kit User Guide 4 1 Acutime 2000 Connections 4 4 1 Interface and Power Connections The black plastic connector located in the base of the Acutime 2000 supports both the interface and power connections The Acutime 2000 uses a 12 pin connector Figure 4 1 illustrates the location of the connector Figure 4 1 Acutime 2000 Interface Connector 4 2 Acutime 2000 Synchronization Kit User Guide 4 Acutime 2000 Connections Figure 4 2 illustrates the pin arrangement for this connector Figure 4 2 Acutime 2000 12 pin Connector format Acutime 2000 Synchronization Kit User Guide 4 3 Acutime 2000 Connections 4 4 2 Interface Cables and Connectors Table 4 1 Antenna Connector MMP Series 68001 2212P1 26C 2212S1 Interface cables for the Acutime 2000 are available in the following standard lengths e 50 15 meter 100 30 meter 200 60 meter 400 120 meter Cont
14. EPHEMERIS Data Report Meaning sv_number BYTE SV PRN number t_ephem SINGLE time of collection weeknum INTEGER ICD 200 Sec 20 3 3 3 Table 20 1 codeL2 BYTE ICD 200 Sec 20 3 3 3 Table 20 1 L2Pdata BYTE ICD 200 Sec 20 3 3 3 Table 20 1 SVacc_raw BYTE ICD 200 Sec 20 3 3 3 Table 20 1 SV_health BYTE ICD 200 Sec 20 3 3 3 Table 20 1 IODC INTEGER ICD 200 Sec 20 3 3 3 Table 20 l T_GD SINGLE ICD 200 Sec 20 3 3 3 Table 20 1 t_oc SINGLE ICD 200 Sec 20 3 3 3 Table 20 1 a_f2 SINGLE ICD 200 Sec 20 3 3 3 Table 20 1 a_f1 SINGLE ICD 200 Sec 20 3 3 3 Table 20 1 a_f0 SINGLE ICD 200 Sec 20 3 3 3 Table 20 1 SVacc SINGLE ICD 200 Sec 20 3 3 3 Table 20 1 cf cf cf cf cf cf cf cf cf cf cf cf Acutime 2000 Synchronization Kit User Guide A 61 Trimble Standard Interface Protocol A Table A 54 Report Packet 58 EPHEMERIS Data Report Continued Meaning 41 IODE BYTE cf ICD 200 Sec 20 3 3 4 42 fit interval BYTE cf ICD 200 Sec 20 3 3 4 43 46 C rs SINGLE cf ICD 200 Sec 20 3 3 4 47 50 delta_n SINGLE cf ICD 200 Sec 20 3 3 4 51 58 M_0 DOUBLE cf ICD 200 Sec 20 3 3 4 59 62 C_uc SINGLE cf ICD 200 Sec 20 3 3 4 63 70 e DOUBLE cf ICD 200 Sec 20 3 3 4 71 74 C_us SINGLE cf ICD 200 Sec 20 3 3 4 75 82 sqrt_A DOUBLE
15. OOARWN O 1 4 SINGLE 5 8 SINGLE 9 12 SINGLE 13 16 SINGLE 16 nsvs BYTE A 74 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Ox7A Command Packet 7A Set or Request NMEA Interval and Message Mask The NMEA mask determines whether or not a given NMEA message will be output If the bit for a message is set the message will be sent every interval seconds To determine the NMEA interval and message mask use the values shown in Table A 64 While fixes are being generated the output order is ZDA GGA GLL VTG GSA GSV RMC Table A 64 Command Packet 7A Definition Subcode Interval Fix interval in seconds Reserved Reserved RMC Reserved GGA GLL VTG GSV GSA ZDA O 20 20 0 20O 20 20O0O O 0O 0O Reserved Acutime 2000 Synchronization Kit User Guide A 75 Trimble Standard Interface Protocol A 0x7B 0x83 A 76 Report Packet 7B NMEA Message Output This packet is sent in response to command packet 7A and has the same data format as packet 7A Report Packet 83 Double precision XYZ Position Fix And Bias Information This packet provides current GPS position fix in XYZ ECEF coordinates If the I O position option is set to XYZ ECEF and the I O double precision option is selected packet 35 the receiver sends this packet each time a fix is computed The data format is
16. Oscillator Drift Rate DOUBLE Oscillator drift meters second Oscillator Bias Uncertainty Acutime 2000 Synchronization Kit User Guide SINGLE Oscillator bias uncertainty meters A 103 Trimble Standard Interface Protocol A Table A 85 Report Packet 8F 0B Continued Meaning 38 41 Oscillator Drift SINGLE Oscillator bias rate uncertainty Uncertainty meters second 42 49 Latitude DOUBLE Latitude in radians 50 57 Longitude DOUBLE Longitude in radians 58 65 Altitude DOUBLE Altitude according to current datum meters 66 73 Satellite ID 8 BYTES Identification numbers of tracking and usable satellites Bytes 66 through 73 identify the tracking and usable satellites A tracked satellite is distinguished from a usable satellite by a negative sign gt appended to its PRN number In this superpacket time is referenced to UTC to correspond to the default PPS timebase To configure the receiver to output time relative to GPS the PPS must be characterized accordingly Command packet 8E 4A enables the PPS to be re defined at run time and stores the new settings in nonvolatile memory bX Note Leap seconds can not be predicted in advance using only the 8F 0B packet A leap second can be identified by observing that the date does not increment after 86400 seconds have elapsed in the current day The date rollover is delayed for the duration of the leap second and the day
17. b a where b is the length of the semi minor axis A set of parameters that describe the satellite orbit very accurately It is used by the receiver to compute the position of the satellite This information is broadcast by the satellites Measurement interval or data frequency as in making observations every 15 seconds Loading data using 30 second epochs means loading every other measurement A set of software computer processor instructions that are permanently or semi permanently resident in read only memory The number of vibrations per second of an audio or radio signal Measured in hertz Hz kilohertz kHz or megahertz MHz GPS frequencies are L1 1575 42 MHz L2 1227 60 MHz Acutime 2000 Synchronization Kit User Guide Glossary 5 Glossary GDOP geodetic datum geoid GPD Glossary 6 Geometric Dilution of Precision GDOP describes how much an uncertainty in pseudo range and time affects the uncertainty in a position solution GDOP depends on where the satellites are relative to the GPS receiver and on GPS clock offsets A mathematical model designed to best fit part or all of the geoid It is defined by an ellipsoid and the relationship between the ellipsoid and a point on the topographic surface established as the origin of datum This relationship can be defined by six quantities generally but not necessarily the geodetic latitude longitude and the height of the origin the two components o
18. refclock_opent fd 9 modem status 6 refclock_ioctl fd 9 flags 20 peer_configt 127 127 29 0 mode 3 vers 4 min 5 max 10 flags Ox00a1 ttl 0 key 0 resolving terrapin trimble com resolving iq trimble com loop_config state 2 freq 40 642 report_event system event event_restart 0x01 status sync_alarm sync_unspe c 1 event event_unspec Oxc010 auth_agekeyst at 1 keys 1 expired 0 key_expire_all at 1 private 3cal2abf peer_config 155 63 31 220 mode 3 vers 4 min 6 max 10 flags 0x0001 ttl key 0 peer_config 155 63 32 173 mode 3 vers 4 min 6 max 10 flags 0x0001 ttl 0 key 0 refclock_transmit at 16 127 127 29 0 palisade_poll unit 0 polling synchronous packet palisade_receive unit 0 1999 131 06355324 000000 palisade_receivet unit 0 bae252dc 06cb4289 Mon May 10 1999 23 55 24 026 refclock_receive at 16 127 127 29 0 peer GPS_PALISADE 0 event event_reach 0x84 status unreach conf 1 event event_reach 0x8014 gt refclock_sample z offset 0 026539 disp 0 000000 std 0 000000 clock_filter offset 0 026539 delay 0 000000 disp 7 937502 std 0 024825 age 0 transmit at 17 to 155 63 31 220 mode 3 transmit at 17 to 155 63 32 173 mode 3 receive at 17 from 155 63 31 220 mode 4 pkt_mode 4 action 1 peer 155 63 31 220 event event_reach 0x84 status unreach conf 1 event ev ent_reach 0x8014 clock_filter offset 0 005294 delay 0 003325 disp 7 937510 std 0 004953 age 0 receive at 17 from 155
19. 52p 36 864 Instsru exe 22p 98 304 ntpq exe 21p 65 536 ntpdate exe 22p 102 400 ntpdc exe 22p 57 344 ntptrace exe 21p 167 936 ntpd exe 18p lt DIR gt debug 9 File s 528 384 bytes 9 601 024 bytes free C ntp gt copy ntpx exe c winnt system32 ntpq exe ntpdate exe ntpde exe ntptrace exe ntpd exe 5 file s copied C ntp gt This operation ensures the NTP service files are available to Windows NT when the system starts 6 20 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration Installing the Service The NTP service must be registered with the Windows NT Service Control Manager and configured to start at system boot To register the service use the command line utility INSTSRV EXE provided with NTP The INSTSRV EXE utility requires a single parameter representing the complete path to the location of the NTPD EXE executable This example assumes Windows NT is installed in C WINNT If your system directory is different modify the path to the NTP executable accordingly 1 Start a command prompt window and change to the directory containing the INSTSRV EXE utility 2 Typeinstsrv c winnt system32 ntpd exe 5 Command Prompt C ntp gt instsry c winnt system32 ntpd exe The NetworkTimeProtocol service was successfully created Don t forget You must now go to the Control Panel and use the Services applet to change the account name and password t
20. A 38 Command Packet3C o o ooo A 39 Command Packet 3F 11 o A 40 Report Packet 40nn sira e a AO ed A ds A 40 Report Packet 4l yon ima a we ae RS A 41 Relationship Between Packet 41 and Packet46 A 42 Report Packet 42 it iii e a A ee A 43 Report Packet 43 urere a ea oia e RO ees a A 44 Report Packet4S ninaa 48 4 4 da a a A 45 Report Packet 40n iii at A A 46 Report Packet 46 3 32 ir ete al a A 47 Report Packet47 gt scapi sa adne o oo A 48 Report Packet 49 ui a ca a des A 49 Report Packet 4A Report Reference Altitude A 49 Report Packet 4A Report Single Precision LLA Position A 50 Acutime 2000 Synchronization Kit User Guide Table A 41 Table A 42 Table A 43 Table A 44 Table A 45 Table A 46 Table A 47 Table A 48 Table A 49 Table A 50 Table A 51 Table A 52 Table A 53 Table A 54 Table A 55 Table A 56 Table A 57 Table A 58 Table A 59 Table A 60 Table A 61 Table A 62 Table A 63 Table A 64 Table A 65 Table A 66 Table A 67 Table A 68 Table A 69 Table A 70 List of Tables Report Packet4B o o o o A 51 Byte 1 Bit Encoding Status 1 A 51 Report Packet4C o o o o o ooo o A 52 Report Packet 4E i e eae o e Ret A cd A 53 Report UTC Parameters 00 A 54 Report Packet54 0 0000 A 55 0x56 Velocity Fix East North Up ENU Report A 56 Report Packet 3T vs
21. Bytes 0 and 1 control the message output format Byte 2 Byte 2 contains the five time parameters described below Time Type This bit defines whether the time tags associated with a position fix are in GPS time or UTC time The default is UTC time Fix Computation Time This bit controls the time and frequency of position fixes The default is ASAP A 32 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Alternatively in the integer second mode the most recent measurements are projected to next integer second and the solution is then valid at this time The benefit of this mode is the standard fix time and a 1 Hz output rate The drawbacks are that some measurement projection is performed and that the fix may be slightly older than with the default option This mode also conforms to the output rate of NMEA Output Time This bit defines whether fixes are automatically output when computed or only sent in response to a packet 37 request The default is automatic output e Synchronized Measurements This bit controls whether all satellite range measurements are required to have the same time tag The default is OFF Slightly older measurements are tolerated on the order of 3 5 seconds to provide solutions when obscurations make it impossible to obtain exactly concurrent measurements from each satellite When this bit is ON all measurements are required to have the same time tag This
22. GPS Satellites in View C 8 C 4 5 RMC Recommended Minimum Specific GPS Transit Data 2 2 ee eee C 9 C 4 6 VTG Track Made Good and Ground Speed C 10 C 4 7 ZDA Time amp Date o C 11 D Specifications and Drawings D 1 Acutime 2000 GPS Smart Antenna Specifications D 1 D 2 Acutime 2000 Standard Interface Cable Diagram D 5 E NTP Diagnostics and Debugging E 1 Diagnostics and Debugging aoaaa E 1 E 1 1 System Log Entries oaa E 1 E 1 2 Error Log Entries e e coco cenas ea datue sna E 3 E 2 Running NTP in Debug Mode 0 E 8 E 2 1 Debug Mode Not Available E 9 E 2 2 NTP Startup and Acutime Poll E 9 E 2 3 Acutime is not Responding E 11 Acutime 2000 Synchronization Kit User Guide ix Contents E 3 E 4 E 5 E 2 4 Running NTP with Event Polling Disabled E 12 E 2 5 Incorrect Port and Bad Data E 15 E 2 6 Serial Port is Unavailable E 16 Compiling the NTP Distribution oaaae E 17 Windows NT Administration o o aaa E 21 E 4 1 Controlling the NTP Service E 21 E 4 2 Removing the NTP Service E 21 Additional Information o eoa e E 23 F Theory of Operation Fl GPS Satellite Message ouaaa F 2 F 2 Satellite Acquisition and Time to First Fix F 3 F 2 1 Cold Start isi aaa e we eh took os beh ae
23. GPS time 4E 35 Set input output options 55 37 Status and values of last position and velocity 57 Note 1 TA Set request NMEA interval and message mask 7B BB Set request receiver configuration BB BC Set request port configuration BC 8E 14 Set request datum value 8E 15 Request datum values 8E 4A Set request PPS characteristics 8E A5 Set request packet broadcast mask 8E A6 Issue self survey command Note 1 Output is determined by packet 35 settings see Table A 3 A 12 Acutime 2000 Synchronization Kit User Guide Trimble Standard Interface Protocol The following packets let you customize receiver operations Table A 13 Advanced Packets Input ID Description Output ID 1E Clear memory reset Note 1 25 Soft reset and self test Note 1 2D Request Oscillator offset 4D 37 Information about last computed fix 57 Note 1 39 Satellite disable or ignore health 59 Note 2 3A Last raw measurement 5A 3B Satellite ephemeris status 5B 3C Tracking status 5C BB Set receiver configuration parameters BB 8E 4A Set PPS characteristics 8F 4A 8E 4E Set PPS output option 8F 4E 8E 4F Set PPS Width Acutime 2000 only 8F 4F 8E 20 Fixed Point Superpacket 8F 20 Note 1 Output is determined by packet 35 settings For packets 1E and 25 see Table to determine which packets are output at power up
24. Land BB BB BB Elevation mask 0 175 radians 10 degrees BB BB BB Signal level mask 4 0 AMU BB BB BB PDOP mask 8 0 BB BB BB PDOP switch 6 0 BB BB BB Foliage mode 0 never BB BB BB DGPS age limit 30 seconds BB BB BB Have reference FALSE 2A 2A 4A altitude flag Reference altitude 0 0 2A 2A 4A meters Table 5 3 OEM Configuration segment 3 Parameter Factory Default Set Request Report Datum index WGS 84 Ellipsoid 8E 14 8E 15 8F 15 Position 0x12 35 35 35 Velocity 0x02 35 35 35 Time 0x01 35 35 35 Auxiliary 0x02 35 35 35 Super packets output 0x32 8E A5 8E A5 8F A5 mask byte 1 Super packets output 0x21 8E A5 8E A5 8F A5 mask byte 2 Auto TSIP output OxFFFFFFFCO 8E 4D 8E 4D 8F 4D mask Acutime 2000 Synchronization Kit User Guide 5 17 System Operation Table 5 4 Parameter Factory default Port A and B Configuration segment 4 Request Input baud rate 9600 BC Output baud rate 9600 BC Parity Odd BC Data bits 8 BC Stop bits 1 BC Input protocol BC Output protocol Table 5 5 Parameter Factory default PPS Configuration segment 5 BC Request PPS enabled switch Enabled 8E 4A PPS timebase UTC 8E 4A Polarity TRUE 8E 4A PPS offset 0 0 Seconds 8E 4A Bias uncertainty threshold 300 0 Meters 8E 4A PPS width 10 0e 6 Sec
25. PDOP mask Depending on how the PDOP mask is set 3 D mode can be restrictive when the receiver is subjected to frequent obscuration or when the geometry is poor due to an incomplete constellation If only a 2 D solution is desired or if the exact altitude is known 2 D manual should be requested In this case the receiver uses either the last altitude obtained in a 3 D fix or the altitude supplied by the user Any error in the assumed altitude affects the accuracy of the latitude and longitude solution Use packet BB to set the desired position fix mode Note Altitude and the fix mode are stored in non volatile memory Acutime 2000 Synchronization Kit User Guide System Operation Overdetermined Clock Mode Overdetermined Clock Mode is used only in stationary timing applications This is Acutime 2000 s default mode After the Acutime 2000 self surveys its static reference position it automatically switches to Overdetermined Clock Mode and determines the clock solution The timing solution is qualified by a T RAIM algorithm which automatically detects and rejects faulty satellites from the solution In this mode the Acutime 2000 does not navigate or update positions and velocities but maintains the PPS output solving only for the receiver clock error bias and error rate bias rate Acutime 2000 Synchronization Kit User Guide 5 5 System Operation 5 5 2 3 5 6 PPS Output Options The PPS Pulse Per Second outpu
26. Trimble Standard Interface Protocol A The tracking status flag allows precise monitoring of receiver tracking status and allows a host system to determine whether the time output by the receiver is valid After self survey has completed the receiver only needs to track one satellite to maintain precise synchronization with UTC Table A 99 Tracking Status Flag Definitions Flag Value Status Meaning DOING_FIXES Receiver is navigating GOOD_1SV Receiver is timing using one satellite APPX_1SV Approximate time NEED_TIME Start up NEED_INITALIZATION Start up PDOP_HIGH Dilution of Precision too High BAD_1SV Satellite is unusable 0SVs No satellites usable 1SV Only 1 satellite usable 2SVs Only 2 satellites usable o0 CO N oO RB WwW NM A oO 3SVs Only 3 satellites usable NO_INTEGRITY Invalid solution DCORR_GEN Differential corrections OVERDET_CLK Overdetermined fixes A 124 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Leap Second Flag Leap seconds are inserted into the UTC timescale to counter the effect of gradual slowing of the earth s rotation due to friction The 8F AD packet provides extensive UTC leap second information to the user application The Leap Scheduled bit is set by the receiver when the leap second has been scheduled by the GPS control segment The Control segment may schedule the leap second several weeks before
27. affects position solutions PDOP A value based on PDOP that defines when the GPS constellation receiver processor should switch between 2 D and 3 D GPS switch modes The PDOP constellation switch is only active when the GPS mode of operation is set to Auto PRN Pseudo random noise Each GPS satellite generates its own distinctive PRN code which is modulated onto each carrier The PRN code serves as identification of the satellite as a timing signal and as a subcarrier for the navigation data protocol A formal set of rules that describe a method of communication The protocol governs the format and control of inputs and outputs pseudo range A measure of the range from the GPS antenna to a GPS satellite Pseudo range is obtained by multiplying the speed of light by the apparent transit time of the signal from the GPS satellite Pseudo range differs from actual range because the satellite and user clocks are offset from GPS time and because of propagation delays and other errors RAM Random Access Memory random access Memory in which information can be referred to in an memory arbitrary or random order The contents of RAM are lost when the System Unit is turned off Acutime 2000 Synchronization Kit User Guide Glossary 9 Glossary range range rate read only memory relative positioning rise set time ROM RTCM Glossary 10 A term used to refer to the distance radio signals can travel before they must be r
28. equipment is connected Then the interpretation and use of packets can be adjusted accordingly Table A 41 Report Packet 4B Status Meaning 0 Machine BYTE 0x61 Acutime 2000 ID 0x62 ACE UTC 1 Status 1 BYTE The Status 1 codes are encoded into individual bits within the byte 2 Status 2 BYTE Super packets are supported The status codes are encoded into individual bits within the bytes The bit positions and their meanings are shown below Table A 42 Byte 1 Bit Encoding Status 1 Status 1 Bit Meaning if bit value 1 Position 0 LSB Not Used Battery Backed Time Clock ACE UTC only Not Used The Almanac stored in the receiver is not complete and current Not used Acutime 2000 Synchronization Kit User Guide A 51 Trimble Standard Interface Protocol A 0x4C Table A 43 Report Packet 4C Operating Parameters Report This packet provides several operating parameter values of the receiver The receiver sends this packet in response to packet 2C The data string is four SINGLE values The dynamics code indicates the expected vehicle dynamics and is used to assist the initial solution The elevation angle mask determines the lowest angle at which the receiver tries to track a satellite The signal level mask sets the required signal level for a satellite to be used for position fixes The PDOP mask sets the maximum PDOP with which position fixes are calculated The PDOP swi
29. three coordinates HDOP Horizontal two horizontal coordinates VDOP Vertical height only TDOP Time clock offset only RDOP Relative normalized to 60 seconds See dilution of precision The apparent change in frequency of a received signal due to the rate of change of the range between the transmitter and receiver Cartesian coordinate system where the X direction is the intersection of the prime meridian Greenwich with the equator The vectors rotate with the earth Z is the direction of the spin axis The angle between the line of sight vector and the horizontal plane Acutime 2000 Synchronization Kit User Guide elevation mask angle ellipsoid ephemeris epoch firmware frequency Glossary A measure of the minimum elevation angle above the horizon above which a GPS satellite must be located before the signals from the satellite will be used to compute a GPS location solution Satellites below the elevation angle are considered unusable The elevation mask angle is used to prevent the GPS receiver from computing position solutions using satellites which are likely to be obscured by buildings or mountains In geodesy unless otherwise specified a mathematical figure formed by revolving an ellipse about its minor axis It is often used interchangeably with spheroid Two quantities define an ellipsoid these are usually given as the length of the semi major axis a and the flattening f a
30. values for use in the position solution This packet allows you to override the internal logic and force the receiver to either unconditionally disable a particular satellite or to ignore a bad health flag The GPS receiver returns packet 59 for operation modes 3 and 6 only Table A 24 Command Packet 39 Meaning Operation Enable for selection default Disable for selection Request enable or disable status of all 32 satellites Heed health on satellite default Ignore health on satellite Request heed or ignore health on all 32 satellites Satellite All 32 satellites Any one satellite PRN number At power on and after a reset the default values are set for all satellites w Caution Ignoring health can cause the GPS receiver software to fail as an unhealthy satellite may contain defective data Use extreme caution in ignoring satellite health Acutime 2000 Synchronization Kit User Guide A 37 Trimble Standard Interface Protocol A 0x3A Command Packet 3A Last Raw Measurement Request This packet requests the most recent raw measurement data for one specified satellite The GPS receiver returns packet 5A if data is available Table A 25 Command Packet 3A Meaning Satellite All satellites in the current tracking set Desired satellite 0x3B Command Packet 3B Satellite Ephemeris Status Request This packet requests the current status of satellite ephemeris data The GPS recei
31. 001 The Acutime NTP reference clock is identified in the list as GPS_ACUTIME The data indicates that the Acutime GPS is selected as reference clock that it was last polled 61 seconds ago and that it has responded to each of the last 11 polls The offset between the system clock and UTC is 17 microseconds with a jitter of 2 microseconds The use of the rv command is also shown above It reveals more information about the reference clock source in use by NTP 6 36 Acutime 2000 Synchronization Kit User Guide NTP Software Installation and Configuration NTP is not Running If NTP is not running on the machine you will see a timeout message ntpq gt pe hostname trimble com timed out nothing received Reguest timed out ntpq gt Problems with NTP and the Acutime NTP reference clock can be observed using NTPQ by monitoring the when and reach fields of the GPS_ACUTIME line item No Response from the Acutime NTP Reference Clock If the Acutime is not responding to NTP poll requests the debug output appears as follows s C WINNT System32 ntpq exe t when poll reach offset ra Trimble COM 155 63 38 190 terrapin Trimbl iq Trimble COM 589 47 xspring ENG Trim LOCAL 0 i 7579 85 x155 63 38 190 GPS 889 22 GPS_PALISADE 2 GPS 4 0 000 xhomer Trimble C iq Trimble COM 579 42 status 06a4 leap_none sync_ntp 10 events event_peer strat_chg processor unknown system WINDOWS NT leap 00
32. 0183 is a simple yet comprehensive ASCII protocol which defines both the communication interface and the data format Since it is a well established industry standard NMEA 0183 has also gained popularity for use in applications other than marine electronics For those applications requiring output only from the GPS receiver NMEA 0183 is a popular choice since in many cases an NMEA 0183 software application code already exists The Acutime 2000 GPS smart antenna is available with firmware that supports a subset of the NMEA 0183 messages GGA and VTG For a nominal fee Trimble can offer custom firmware with a different selection of messages to meet your application requirements This appendix provides a brief overview of the NMEA protocol and describes both the standard and optional messages offered by the Acutime 2000 For a complete copy of the NMEA 0183 standard contact NMEA National Office PO Box 3435 New Bern NC 28564 3435 U S A Telephone 1 919 638 2626 Fax 1 919 638 4885 Acutime 2000 Synchronization Kit User Guide C 1 NMEA 0183 C C 1 The NMEA 0183 Communication Interface NMEA 0183 allows a single source talker to transmit serial data over a single twisted wire pair to one or more receivers listeners The table below lists the characteristics of the NMEA 0183 data transmissions Table C 1 NMEA 0183 Characteristics Signal Characteristic NMEA Standard Baud Rate 4800 Data Bits 8 Parity None Dis
33. 2 2 Nomenclature Historically the ports of the Smart Antenna product lines which include Acutis Acutime and Palisade products have been described using letters A and B The board level products such as Lassen Ace and Core Module 3 have historically used port numbers 1 and 2 to label the ports on the starter kit The Acutime 2000 ports are referenced by letters A and B conformant to standards established by the Palisade product line The Ace UTC ports are referenced by numbers conformant with the conventions of previous board level products This manual reconciles the naming schemes of both receiver lines and generally refers to the ports using the Ace UTC convention of using 1 and 2 Exclusively where designations apply only to Acutime 2000 the ports will be referenced as letters A or B The following tables can be used to cross reference the port identifiers Table A 1 Ace UTC Port Translation Table Function Label Internal Primary Port 1 Port 0 Secondary Port 2 Port 1 Table A 2 Acutime 2000 Port Translation Table Function Label Internal TSIP Port B Port 0 Timing Port A Port 1 Protocol Capabilities The I O ports of Ace UTC and Acutime 2000 are highly configurable Port settings are stored in non volatile memory and are retained across power outages Acutime 2000 Synchronization Kit User Guide Trimble Standard Interface Protocol For sy
34. 40 report packets A 16 Acutime 2000 Synchronization Kit User Guide Index 3 0x4C Operating Parameters Report A 52 0x4E GPS Time Change Acknowledgment A 53 0x57 Information About Last Computed Fix Report A 57 0x59 Satellite Attributes Database Report A 63 Ox5A Raw Measurement Data Report A 64 Ox5C Satellite Tracking Status Report A 68 0x5F EEPROM Segment Status Reports A 70 U unit number 6 12 UNIX installation 6 24 hardware configuration 6 28 update notes xxii update rate F 8 WwW warm start F 4 Windows NT installation 6 15 automatic 6 16 manual 6 17 World Wide Web WWW site xxii Index 4 Acutime 2000 Synchronization Kit User Guide Reader Comment Form Acutime 2000 Synchronization Kit User Guide April 2001 P N 45005 00 ENG Revision A We appreciate your comments and suggestions for improving this publication Contributors of particularly helpful evaluations will receive a thank you gift I use the following Trimble product for Please circle a response for each of the statements below 1 Strongly Agree 2 Agree 3 Neutral 4 Disagree 5 Strongly Disagree The manual is well organized 1 2 3 4 5 I can find the information I want 1 2 3 4 5 The information in the manual is accurate 1 2 3 4 5 I can easily understand the instructions 1 2 3 4 5 The manual contains enough examples 1 2 3 4 5 The examples are appropriate and helpful 1 2 3 4 5 The layout and format are attractive and use
35. 6 SEC Station health UINT8 Number of SVs in packet Bits 0 5 Type 9 flag Bit type 1 type 9 Version 2 flag Bit must be set Acutime 2000 Synchronization Kit User Guide A 71 Trimble Standard Interface Protocol A The next 5 bytes are repeated as a group for each satellite The SV PRN and scale factor contains the SV PRN in the lower 5 bits and the scale factor in the upper 3 bits Range corrections are scaled by 0 02 meters times 2 raised to the scale factor power Range rate corrections are scaled by 0 002 meters per second times 2 raised to the scale factor power The format is shown in Table A 61 Table A 61 Report Packet 0x60 Data Formats for Health and Power Bye on rem Type vane Definition 4 N 5 SVPRN fo31 on is Sv 32 4 N 5 5 7 Scale factor Low Scale factor 02m 002 m s High Scale factor 32m 032 m s Correction not usable Range UINT16 RTCM 104 correction Range rate UINT8 RTCM 104 correction IODE UINT8 A 72 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x61 Command Packet 0x61 Set Differential GPS Corrections This TSIP packet provides the delta differential corrections from RTCM 104 record type 2 There is no response to this packet Scale factors are version 1 unless the version 2 flag is set The format for this packet is shown in Table A 62 Table A 62 Command Packet 0x61 Data Form
36. 89 Table A 90 Table A 91 Table A 92 Table A 93 Table A 94 Table A 95 Table A 96 Table A 97 Table A 98 Table A 99 Table A 100 xvi Command Packet 8E 14 o A 87 Command Packet 8E 14 A 88 Command Packet 8E 20 o A 89 Command Packet Ox8E 45 o o A 90 Command Packet 8E4A o o ooo A 91 Command Packet 8E4D 0 oo A 92 Command Packet 8E 4D Packets Affected By Bits A 93 Command Packet 0x8E 4 o o A 95 Command Packet 0x8E4F 0 o o o A 95 Command Packet 8E A5 o ooo A 97 Command Packet 8E A6 oo A 98 Command Packet 8E A9 Data Format lt lt segment 7 gt gt A 99 Command Packet 8E AB A 100 Command Packet 8E AC ooo A 101 Report Packet 8F 0B o oo A 103 Report Packet 8E 14 0 0 o o A 105 Report Packet 8 20 0 0 o o A 106 Report Packet 8F 20 o o ooo A 107 Report Packet Ox8F 26 o oo A 108 Report Packet 8F 41 o o ore a cci e aoi e m o o A 109 Report Packet 8F 42 aaa o oo A 110 Command Packet 8E AD o o A 111 Report Packet 8E 4A 0 0 0 0 o o A 112 Report Packet 8F 4D 0 0 o ooo A 113 Report Packet 8F 4D 0 0 o oo A 113 Report Pa
37. 8F AD packet on port 1 The time reported by the 8F AD packet on port is always the beginning of the current second A 102 Acutime 2000 Synchronization Kit User Guide A 0x8F 0B Report Packet 8F 0B Comprehensive Time Trimble Standard Interface Protocol The output of the packet is synchronized with the PPS and may also be generated in response to external events Report packet 8F 0B provides easy identification of each timing pulse and contains all the information required for most timing and synchronization applications Output of this packet can be disabled and configured using the 8E A5 packet on Port 1 If output of the 8F AD packet is also enabled the 8F 0B packet will always be output after the 8F AD packet The packet contains 74 bytes in the following order Table A 85 Subpacket ID Report Packet 8F 0B BYTE Meaning Subcode 0x0B Event Count INTEGER External event counter Zero for PPS UTC GPS TOW DOUBLE UTC GPS time of week seconds Date BYTE Date of event or PPS Month BYTE Month of event or PPS Year INTEGER Year of event or PPS Receiver Mode BYTE Receiver operating dimensions 0 Horizontal 2D 1 Full position 3D Survey Single satellite OD Automatic 2D 3D DGPS reference Clock hold 2D Overdetermined clock default UTC Offset INTEGER UTC offset value seconds Oscillator Bias DOUBLE Oscillator bias meters
38. A 97 Report Packet 8F AC Byte Bit Item Type Value Meaning 0 Subcode BYTE OxAC 1 Receiver BYTE 0 Automatic 2D 3D Mode 1 Single Satellite Time 3 Horizontal 2D 4 Full Position 3D 5 DGPS Reference 6 Clock Hold 2D 7 Overdetermined Clock 2 Reserved 3 Self Survey BYTE 0 100 Percent completed Progress 4 7 Reserved 8 9 Reserved 10 11 Minor Alarms UINTEGER Bit field Bit 1 Antenna Open Bit 2 Antenna Shorted Bit 3 Not tracking satellites Bit 5 Survey in progress Bit 6 No stored position Bit 7 Leap second pending Bit 8 In test mode Bit 10 EEPROM segments status Bit 11 Almanac status 12 GPS BYTE 0 Doing fixes Decoding 1 Do not have GPS time Status 3 PDOP is too high 8 No usable satellites 9 Only 1 usable satellite Ox0A Only 2 usable satellites Ox0B Only 3 usable satellites 0x0C The chosen satellite is unusable 0x10 TRAIM rejected the fix Acutime 2000 Synchronization Kit User Guide A 121 Trimble Standard Interface Protocol Table A 97 Report Packet 8F AC Continued Byte Bit Item Type Value Meaning 13 Reserved 14 Reserved 15 Reserved 16 19 Bias SINGLE Estimate of UTC GPS offset ns of local clock 20 23 Bias Rate SINGLE Estimate of UTC GPS offset ppb of local clock 24 27 Reserved 28 31 Reserved 32 35 Reserved 36 43 Latitude DOUBLE Radians 44 51 Longitude DOUBLE Radians 52 59 Altitude DOUBLE Meters 60 63 PPS Single
39. AD on Port 1 15 0x8F AD O 0 Synchronous Ox8F AD on Port 1 3 4 0 15 Bit O Reserved always 0 field Acutime 2000 Synchronization Kit User Guide A 97 Trimble Standard Interface Protocol A 0x8E A6 Command Packet 8E A6 Issue Self Survey Command This command packet starts a self survey The ACE UTC GPS responds with report packet 8F A6 This command has no effect when survey is disabled Table A 81 Command Packet 8E A6 Subcode Self survey Restart self survey command 0x8E A9 Command Packet 8E A9 Set Self Survey Parameters Use command packet 8E A9 to set the self survey parameters or to request the current settings The ACE UTC GPS replies with response packet 8F A9 Data Fields Self Survey Enable Use this field to enabled or disabled the self survey mechanism 0 Disable the self survey mechanism 1 Enable the self survey mechanism Position Save Flag Use this field to tell the self survey mechanism to automatically save or to not save the self surveyed position at the end of the self survey procedure 0 Do not automatically save the surveyed position when the self survey is complete A 98 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 1 Automatically save the surveyed position when the self survey is complete Self Survey Length Use this field to specify the number of position fixes that are to be averaged together to form the self surveyed p
40. Configuration Information 6 14 6 6 Windows NT Installation 6 15 6 6 1 Automatic Installation 6 16 6 6 2 Manual Installation o 6 17 6 6 3 Starting the Service o 6 23 6 7 UNIX Installation o o e 6 24 6 7 1 Create the Configuration File 6 25 6 7 2 Set Up Device Links o o o 6 26 6 7 3 Hardware Configuration 6 28 6 7 4 Copying Executable Files 6 29 6 7 5 System Initialization o o 6 30 6 7 6 Start NTP iaa a iia 6 31 Acutime 2000 Synchronization Kit User Guide vii Contents viii 6 8 Monitorins NEP cocoa ao ca e BAY a ia 6 31 6 8 1 NTP Events on Windows NT 6 32 6 8 2 UNIX System Log Files 6 34 6 8 3 NTPQ The NTP Query Utility 6 35 Trimble Standard Interface Protocol A l A 2 A 3 A 4 AS A 6 A 7 A 8 A 9 A 10 A 11 A 12 A 13 A 14 A 15 A 16 A 17 A 18 A 19 Interface Scopes uaa ch bay wd e alt eds ed A 1 A 1 1 Packet Structure o o A 2 Physical Interface Characteristics A 3 A 2 1 Nomenclature o e A 4 A 2 2 Protocol Capabilities o A 4 A 2 3 Event Mpt uos anian Gada dee a bark we A 6 Packets Output at Power Up 004 A 6 Receiver Warm Start o oo ea he ee e
41. Interface Module are not currently used by the Acutime NTP reference clock driver and do not require connection They are available for other applications such as backup timing interfaces on the time server Acutime 2000 Synchronization Kit User Guide 6 9 NTP Software Installation and Configuration 6 6 5 NTP Software Installation NTP software installation consists of copying the NTP program and utilities to the host system s fixed disk and configuring the system to start NTP after booting The same NTP software can be used on servers and client workstations This versatility allows efficient reconfiguration of time servers to function with the Acutime NTP reference clock if necessary 6 10 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 5 1 NTP Configuration File The NTP configuration file NTP CONF is a human readable text file which contains information about security settings time servers and reference clocks NTP reads the information in this file at startup and initializes itself according to the configuration entries The order of the line items in the configuration file is arbitrary You must edit the configuration file for the serial port connection on your system You should also include any available time servers on your network bX Note The configuration file is a security sensitive file It should be protected from accidental or intentional modification by use
42. Kit User Guide A Trimble Standard Interface Protocol Ox8F 41 Report Packet 8F 41 Manufacturing Parameters This packet provides information on the manufacturing parameters stored in nonvolatile memory in response to command packet 8E 41 Table A 90 Report Packet 8F 41 Meaning Subcode BYTE ID for this subpacket is always 0x41 Board serial number prefix INTEGER Board serial number ULONG Year of build BYTE Month of build BYTE Day of build BYTE Hour of build BYTE Oscillator offset SINGLE Test code identification number INTEGER Acutime 2000 Synchronization Kit User Guide A 109 Trimble Standard Interface Protocol A 0x8F 42 Report Packet 8F 42 Production Parameters This packet provides information on the production parameters stored in nonvolatile memory in response to command packet 8E 42 Table A 91 Report Packet 8F 42 Meaning Subcode BYTE ID for this subpacket is always 0x42 Production options prefix BYTE Production number extension BYTE Case serial number prefix INTEGER Case serial number ULONG Production number ULONG Reserved INTEGER Machine identification number INTEGER Reserved INTEGER 0x8F 45 Report Packet 8F 45 This report packet is output after the command packet 8E 45 has been executed See the corresponding command packet for information about the data formats A 110 Acutime 2000 Synchronization Kit User Guide A
43. Kit User Guide A Trimble Standard Interface Protocol Table A 68 Vaild GPS Configuration Settings Survey State Active Configuration Dynamics Code Operating Dimension Survey Disabled Mobile any any Survey Active Survey Land Sea Air 2D or 3D or Auto Survey Complete Timing Stationary 1SV or Over determined Send packet BB with subcode 0 as the only data byte to query for the primary receiver configuration The receiver will respond with report packet BB The table below lists the individual fields within the BB packet When sending this packet enter OxFF or 1 0 to leave any parameter unchanged Dynamics Code The default is LAND mode where the receiver assumes a moderate dynamic environment In this case the satellite search and re acquisition routines are optimized for vehicle type environments In SEA mode the search and re acquisition routines assume a low acceleration environment and the receiver reverts to the user entered altitude in 2 D auto In AIR mode the search and re acquisition routines are optimized for high acceleration conditions Elevation Mask This is the minimum elevation angle for satellites to be used in a solution output by the receiver Satellites near the horizon are typically more difficult to track due to signal attenuation and are also generally less accurate due to higher variability in the ionospheric and tropospheric corruption of the signal When there are no obstructions the receiver can generall
44. Note 2 Not all modes of packet 39 cause a reply see the description for packet 39 page A 37 Acutime 2000 Synchronization Kit User Guide A 13 Trimble Standard Interface Protocol A A 12 Command Packets Sent to the Receiver Table A 14 summarizes the command packets sent to the receiver It includes a short description of each packet and the associated output packet In some cases the response packets depend on user selected options These selections are described beginning on page A 20 Table A 14 Command Packets Sent to the Receiver Packet Description Output ID Oscillator Offset Reset receiver Software version Almanac Current GPS time Fix Mode select Initial position XYZ Cartesian ECEF Receiver position fix mode Soft reset and self test Receiver health Signal levels GPS system message Almanac health page Altitude for 2 D mode Initial position LLA Operating parameters Oscillator offset Set GPS time UTC parameters Accurate initial position XYZ Cartesian ECEF Accurate initial position LLA Satellite for 1 SV mode I O options 55 Status and values of last position and velocity 57 Note 4 A 14 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Table A 14 Command Packets Sent to the Receiver Continued Packet Description Output ID Load satellite system data 58 Satellite ena
45. PPS quantization error ns Quantization Error 64 PPS output UINT8 0 PPS Not Generated status 1 PPS Was Generated 65 67 Reserved A 122 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x8F AD Report Packet 8F AD Primary UTC Time The output of the 8F AD packet is synchronized with the PPS and may also be generated in response to external events This packet provides accurate time and date information for time stamping and time transfer The leap flag provides complete UTC event information allowing implementation of sophisticated distributed systems intended to operate synchronously with UTC time This packet is always output first in a possible sequence of up to 4 synchronous packets Output of this packet can be disabled and configured using the 8E AD packet Table A 98 Report Packet 8F AD Meaning Subpacket ID BYTE Subcode 0xAD Event Count INTEGER External event counter Zero for PPS Fractional DOUBLE Time elapsed in current second seconds Second Hour BYTE UTC Hour Minute BYTE UTC Minute Second BYTE Second 0 59 60 leap Day BYTE Date 1 31 Month BYTE Month 1 12 Year INTEGER Year 4 digit Receiver BYTE Tracking Status see definition below Status UTC Flags BYTE Leap Second Flags see definition below Reserved BYTE Contains OxFF Reserved BYTE Contains OxFF Acutime 2000 Synchronization Kit User Guide A 123
46. Packet 1E Initiate Cold or Factory Reset This command packet tells the receiver to perform either a cold reset or a factory reset A cold reset clears all navigation data for example almanac and ephemeris stored in RAM and is equivalent to a power cycle A factory reset also restores the factory defaults for all configuration and navigation parameters stored in non volatile memory This packet can affect separately the configuration parameters and navigation parameters It contains one data byte equal to one of the following ASCII letters K F C N or R Table A 18 Command Packet 1E Response K 0x4B Cold reset FP 0x46 Factory reset C 0x43 Compatibility re start for the Palisade firmware version v7 02 Clear navigation data in EEPROM and cold reset N 0x4E R 0x52 Set configuration parameters in EEPROM to factory defaults w Caution The factory reset commands 0x1E F and 0x1E R will delete the stored position and cause a self survey to restart All almanac ephemeris current position mode and communication port setup information stored in RAM is lost by the execution of these commands 0x1 F Command Packet 1F Software Versions Request This packet requests information about the version of software running in the Navigation and Signal Processors This packet contains no data bytes The GPS receiver returns packet 45 Acutime 2000 Synchroniza
47. Port 1 short sendb unsigned char db put_char outputs a character to the serial port it returns 0 for success and 1 for failure ee return put_char PORT db Format a command for sending to a TSIP receiver void send_cmd TSIPPKT cmd short i sendb DLE sendb cmd gt code for i 0 i lt cmd gt cnt i if cmd gt buf i DLE sendb DLE sendb cmd gt buf i sendb DLE sendb ETX Acutime 2000 Synchronization Kit User Guide A 135 Trimble Standard Interface Protocol de de de de de de El short end_of_rptpkt TSIPPKT rpt A To issue command packet 0x41 to request software version from the ACE UTC GPS use the following routine Request software version void cmd_0x1F void TSIPPKT cmd cmd cnt 0 cmd code send_cmd cmd 0x1F Handling incoming TSIP packet 0x45 Report routines handle incoming receiver packets They call the routine end_of_rptpkt which accumulates from the serial buffer unstuffs these bytes and checks whether the end of packet sequence lt DLE gt lt EXT gt has been received fine FALSE 0 fine TRUE FALSE fine INCOMPLETE 0 fine HAVE_DLE dL fine COMPLETE 2 fine MAXEND_RPTBUF 256 been received short this_byte A 136 for 77 this_byte getb if this_byte 1 return FALSE
48. The serial port setting can be changed and stored in serial EEPROM using a TSIP command This port can also be configured to transmit timing packets using packet 8E A5 to determine which timing packet to output on this port Port A Timing The Acutime 2000 has a dedicated serial port for outputting comprehensive time packets Messages are output after the PPS and after external events The factory default setting is TSIP 9600 8 odd 1 output only The host system receives both the PPS and the time packet identifying each pulse Use packet 8E A5 to determine which timing superpacket to output on this port The Acutime 2000 generates a packet in response to the external event input The event count field in packet 8F 0B or 8F A D increments for each event received This field resets after a power cycle and rolls over at 65535 The event tag messages are interleaved with the PPS messages PPS tags are distinguished by a zero 0 in the event count field The Acutime 2000 accepts external events up to a Acutime 2000 Synchronization Kit User Guide 5 System Operation 10 Hertz rate Use packet 8E A5 to configure this port to output the 8F 0B or 8F AD packet in response to external events Acutime 2000 Synchronization Kit User Guide 5 11 System Operation 5 5 4 5 12 GPS Timing In many timing applications such as time frequency standards site synchronization systems wireless voice and data networks and event measurem
49. Trimble Standard Interface Protocol 0x8E AD Command Packet 8E AD Request 8F AD Request or Configure Super Packet Output If the 8E AD byte sequence is sent with no data the receiver will generate an 8F AD packet on port B The time reported by the 8F AD packet on port B is always the beginning of the current second Output of the 8F AD Primary UTC timing packet on Port A is configured by sending a 3 byte message 8E AD n where n ranges from 0 to 3 as defined below The receiver returns the 8F A5 Super Packet Output Mask Table A 92 Command Packet 8E AD Default Meaning Subcode Required Super packet ID Flag 0 3 Disable packet output on port A Output packet on port A only at PPS Output packet on port A only at event input Output at both event input and PPS Acutime 2000 Synchronization Kit User Guide A 111 Trimble Standard Interface Protocol A 0x8F 4A Report Packet 8F 4A PPS Characteristics This packet reports ACE UTC s PPS characteristics This packet is sent in response to a query or control command with packet 8E 4A The packet contains 16 bytes in the following order Table A 93 Report Packet 8F 4A Subpacket ID BYTE Always 0x4A PPS Driver Switch BYTE 0 Off 1 On Time Base BYTE 0 GPS 1 UTC default PPS Polarity BYTE 0 Positive default 1 Negative PPS Offset or DOUBLE seconds Cable Delay Bias Uncertainty SINGLE meters Threshold A 112
50. a self survey procedure is in progress When 1 indicates that there is no accurate position stored in EEPROM When 1 indicates that the GPS system has alerted the GPS that a leap second transition is pending When 1 indicates that the GPS is operating in one of its test modes When 1 indicates that the accuracy of the position being used for a time only fix is questionable While operating in the Overdetermined Clock mode which is most of the time with at least 2 satellites available the receiver can detect position inaccuracies as small as 1 2 to mile If this bit is set it is likely that the receiver is using a stored position but has been moved to a new site The stored position should be cleared packet 0x8E 45 and a new position should be established either by user input packet 0x31 or 0x32 or by self survey packet 0x8E A6 When 1 indicates that one or more EEPROM segments where found to be corrupt at reset and had to be set to their factory default settings Use packet 0x3F 11 to retrieve details about which segments where corrupt and to clear this bit The GPS will send packet Ox5F 11 with the segment status Only bits 2 12 of the segment status are used to set this alarm bit When 1 indicates that the almanac is not current or complete Acutime 2000 Synchronization Kit User Guide A 119 Trimble Standard Interface Protocol A GPS Decoding Status This field indicates the decoding status of the GPS receiver
51. aag F 3 F2 2 Watm Stat a Se Go Oo ae a F 4 F 2 3 Garage Search Strategy F 5 F 2 4 HOt Starts sis ob ahh pb a Beko bo waved aw de F 5 F3 Position Accuracy os ces 2 0 0 2 0 0 0 002 eee eee F 6 F3 1 Selective Availability S A o F 6 F4 Coordinate Systems o e F 7 F4 1 PSTD ences dite glee Sch ee eR kk Be eee OE at te Was F 7 F4 2 NMEA OLS 3 00 vis as ass Bit ie ta F 7 FS Performance Characteristics o F 8 F5 1 Update Rate eid se bee the oe Ba thay He ee a F 8 F5 2 Dynamic Limits o F 8 F5 3 Re Acquisition o o e 0000 F 8 F6 System Architecture o o o F 10 Glossary Index Acutime 2000 Synchronization Kit User Guide List of Figures Figure 1 1 Figure 2 1 Figure 3 1 Figure 4 1 Figure 4 2 Figure 5 1 Figure 5 2 Figure 6 1 Figure 6 2 Figure 6 3 Figure 6 4 Figure D 1 Figure D 2 Figure F 1 Figure F 2 Acutime 2000 GPS Smart Antenna Enclosure Connection Diagram Mounted Antenna Acutime 2000 Interface Connector Acutime 2000 12 pin Connector format PPS Quantization Error EE e Removing the Quantization Error from the PPS Oivi Time Transfer Connection Diagram NTP Configuration File Disabling Serial Port Services Using an Administrative Tool Sample UNIX Log Entries Acutime 2000 Standard Interface Cable NTP Interface Cable A Acutime 2000 Block Diagram RS 232 Ver
52. an extra lt DLE gt byte stuffing These extra lt DLE gt bytes must be added stuffed before sending a packet and removed unstuffed after receiving the packet Note A simple lt DLE gt lt ETX gt sequence does not necessarily signify the end of the packet as these can be bytes in the middle of a data string The end of a packet is lt ETX gt preceded by an odd number of lt DLE gt bytes Multiple byte numbers integer float and double follow the ANSI IEEE Std 754 IEEE Standard for Binary Floating Point Arithmetic as illustrated below They are sent most significant byte first This may involve switching the order of the bytes as they are normally stored in Intel based machines Only the fractional part of the mantissa for real numbers SINGLE and DOUBLE is reported because the leading bit on the mantissa is always 1 Specifically INTEGER is a 16 bit unsigned number sent in two s complement format SINGLE float or 4 byte REAL is sent as a series of four bytes it has a precision of 24 significant bits approximately 6 5 digits Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol DOUBLE 8 byte REAL is sent as a series of eight bytes a b c d e f g h it has a precision of 52 significant bits a little better than 15 digits The TSIP protocol is the primary protocol used by the Ace UTC and Acutime 2000 receivers This document describes in detail all TSIP packet iden
53. certain threshold The Acutime 2000 s default configuration provides optimal timing accuracy The only item under user or host control that can affect the Acutime 2000 s absolute PPS accuracy is the delay introduced by the interface cable For long cable runs this delay can be significant 1 25 nanoseconds per foot TSIP packet 8Ex4A sets the cable delay parameter which is stored in non volatile memory For the best absolute PPS accuracy adjust the cable delay to match the installed cable length The cable delay is 1 25 nanoseconds per foot of cable To compensate for cable delay use a negative offset to advance the PPS output Acutime 2000 Synchronization Kit User Guide 5 13 System Operation 5 Timing Pulse Output PPS A pulse per second PPS 1 microsecond wide pulse is available on the Acutime 2000 s interface connector The pulse is sent once per second and the leading edge of the pulse is synchronized to UTC or GPS time The pulse shape is affected by the distributed capacitance of the attached cabling and input circuit The leading edge is typically less than 20 nanoseconds wide The pulse s trailing edge should never be used for timing applications An accurate timing pulse is available only when the Acutime 2000 is operating in the static Overdetermined Clock mode bX Note GPS time differs from UTC Universal Coordinated Time by a small sub microsecond offset and an integer second offset The small offset is the
54. cold starts bX Note If the receiver altitude is set above 18 000 m the receiver will be forced to reset each time it acquires satellites This is implemented to conform with the COCOM industry standard Acutime 2000 Synchronization Kit User Guide A 25 Trimble Standard Interface Protocol A 0x2B 0x2D A 26 Command Packet 2B Initial Position Latitude Longitude Altitude Command This packet provides the GPS receiver with an approximate initial position in latitude and longitude coordinates WGS 84 This packet is useful if the user has moved more than about 1 000 miles since the previous fix Note The GPS receiver can initialize itself without any data from the user this packet merely reduces the time required for initialization This packet is ignored if the receiver is already calculating positions The cold start default LLA position is 0 0 0 The data format is shown below Table A 20 Command Packet 2B Latitude radians north Longitude radians east Altitude meters The GPS receiver returns packet 4C Command Packet 2D Oscillator Offset Request This packet requests the calculated offset of the GPS receiver master oscillator This packet contains no data The GPS receiver returns packet 4D hex This packet is used mainly for service Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x2E Command Packet 2E GPS Time Command This packet p
55. commands similar to cd dev ln s ttySO dev Acutime0 Creation of a symbolic link for Acutime NTP reference clock unit 1 connected to the second serial port tt yb is shown below for a Solaris system The link for unit 0 has already been established and remains unused in this configuration Jol x cd dev ls 1 palisade 1 root other 4 Nov 3 1998 palisadeO gt ttya ls 1 tty 1 root root 6 Feb 2 1995 ttya gt terma 1 root root 6 Feb 2 1995 ttyb gt term b In s ttyb devpalisadel ls 1 palisade 1 root other 4 Nov 3 1998 palisade gt ttya 1 root other 4 May 10 00 17 palisadel gt ttyb cat etc motd Sun Microsystems Inc SunOS 5 5 Generic November 1995 lucky_first 6 26 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 1 Replace the string tt yb in the 1n command with the appropriate serial port designator for your system 2 Replace the number 1 in the string dev Acutimel with the unit number in your NTP configuration file Serial port designators on UNIX systems are usually designated by dev cuau or dev tt yu where u may be composed of one or more alphanumeric characters The following table may assist you in locating the appropriate serial port and symbolic link names for your system Verify presence of the actual device files and validity of all links in the DEV directory before using a serial device Table 6 1 System Serial Ports and Symb
56. down convert and decode the GPS signal and to generate the PPS output signal Since a fixed frequency oscillator is used the Acutime 2000 must place the PPS output on the clock edge that it determines is closest to UTC or GPS This situation results in a quantization error on the placement of the PPS whose magnitude is equal to one half the period of the fixed frequency oscillator The oscillator frequency is 12 504 MHz which is equivalent to a period just under 80 nanoseconds therefore the quantization error on the PPS output is between 40ns Figure 5 1 illustrates quantization error The top waveform represents the 12 504 MHz clock The Acutime 2000 PPS output must be placed on one of the rising edges of this clock The middle waveform represents the UTC GPS on time mark as determined by the Acutime 2000 s GPS receiver electronics The bottom waveform represents the Acutime 2000 s PPS output which is output on the clock edge closest to the actual UTC GPS on time mark 12 504 Mhz Clock UTC or GPS PPS Acutime 2000 PPS Figure 5 1 PPS Quantization Error The amount of quantization error present on each PPS output pulse is reported in packet O0x8F AC This quantization error information can be used to reduce the effective amount of jitter on the PPS pulse Acutime 2000 Synchronization Kit User Guide 5 7 System Operation 5 Figure 5 2 illustrates the result of removing the quantization error from the PPS output
57. files copied during installation as well as the configuration file must be manually removed from the system if a permanent installation is desired This concludes the manual Windows NT installation The remaining part of this section describes the Windows NT specific control event logging and diagnostics features available Acutime 2000 Synchronization Kit User Guide E NTP Diagnostics and Debugging E 5 Additional Information For up to date hardware software and configuration information please refer to the Trimble Navigation NTP Web Site at www trimble com oem ntp Acutime 2000 Synchronization Kit User Guide E 23 NTP Diagnostics and Debugging E E 24 Acutime 2000 Synchronization Kit User Guide F Theory of Operation This chapter describes the smart antenna s satellite acquisition and tracking processes performance characteristics and system architecture This discussion assumes you are familiar with basic GPS theory The smart antenna s satellite acquisition and tracking algorithms can achieve a position solution without any initialization The receiver tracks up to eight satellites and automatically selects the best combination of satellites to compute position velocity and time As satellites move out of view the smart antenna automatically acquires new Satellites and includes them in the solution set as required Before proceeding to the detailed discussion of the satellite acquisition and tracking process please r
58. for all the satellites in the system Acutime 2000 Synchronization Kit User Guide Glossary 1 Glossary ASCII auto GPS mode azimuth angle bandwidth baud bit bit rate byte Glossary 2 American Standard Code for Information Interchange A standard set of 128 characters symbols and control codes used for computer communications ASCII characters require 7 bits of data to send but are often sent 8 bits at a time with the extra bit being a zero A procedure of automatically determining either a 2 D or 3 D position using signals received from GPS satellites The solution automatically transitions between 2 D and 3 D depending on the number of satellites available the PDOP of the available satellites and the defined PDOP switch value See PDOP and PDOP constellation switch The angle of the line of site vector projected on the horizontal plane measured clockwise from true North The range of frequencies occupied by a signal Also the information carrying capability of a communication channel or line A measure of the speed of data transmission Baud and bit rate are the same for direct equipment interconnections for example through RS 232 Baud and bit rate are not the same for modulated data links whether wire or radio Binary digit The smallest unit of information into which digital data can be subdivided and which a computer can hold Each bit has only two values e g on off one zero true false
59. in View Message Parameters Description Total number of GSV messages Message number 1 to 3 Total number of satellites in view Satellite PRN number Satellite elevation in degrees 90 Maximum Satellite azimuth in degrees true 000 to 359 Satellite SNR C No null when not tracking 9 10 11 PRN elevation azimuth and SNR for second satellite 12 13 14 15 PRN elevation azimuth and SNR for third satellite 16 17 18 19 PRN elevation azimuth and SNR for fourth satellite hh Checksum Acutime 2000 Synchronization Kit User Guide C NMEA 0183 C 4 5 RMC Recommended Minimum Specific GPS Transit Data The RMC message contains the time date position course and speed data provided by the GPS navigation receiver A checksum is mandatory for this message and the transmission interval may not exceed two seconds All data fields must be provided unless the data is temporarily unavailable Null fields may be used when data is temporarily unavailable SGP RMC hhmmss s A 1111 111 a yyyyy yyy a x X X XXXXXX X X a hh lt CR gt lt LF gt Table C 7 RMC Recommended Minimum Specific GPS Transit Data Message Parameters Description UTC of Position Fix Status A Valid V navigation receiver warning Latitude N North or S South Longitude E East or W West Speed over the ground SOG in knots Track made good in degrees true Date dd
60. in a user system The top plot shows the offset of the PPS output pulse relative to a stable standard such as a Cesium atomic clock The quantization error is responsible for the jagged appearance of the waveform The middle plot shows the quantization error as reported by the Acutime 20000 in packet 0x8F AC The bottom plot is the result of subtracting the quantization error from the PPS offset PPS Offset ns T E pl o Lu z 2 o N Z o 5 Ox ime second 200 300 Time seconds Corrected PPS Offset ns Figure 5 2 Removing the Quantization Error from the PPS Output 5 8 Acutime 2000 Synchronization Kit User Guide 5 System Operation 5 2 5 External Event Input The Acutime 2000 provides an External Event Input that allows the user to time tag external event pulses The event capture mechanism is triggered on the low to high transition of the external event input The time tag provides a resolution of 320 nanoseconds and represents the time at which the event pulse occurred at the Acutime 2000 connector input Therefore it is offset by the amount of delay in the cable The time tag information is reported in packet 0x8F 0B or 8F AD This feature is intended for use with relatively infrequent event pulses A practical limit on event pulse frequency is about 10 Hz To prevent the Acutime 2000 hardware and firmware from being overrun with event pul
61. is for satellite 1 and so on The receiver sends this packet in response to packet 29 and when this data is received from a satellite Table A 38 Report Packet 49 health of satellite 1 health of satellite 2 health of satellite 432 In each data byte of this packet a value 0 indicates that the satellite is healthy all other values indicate that the satellite is unhealthy Report Packet 4A Reference Altitude or Single Precision LLA Position Fix Report The Reference Altitude variation of the packet is returned in response to command packet 2A when setting or requesting reference altitude Table A 39 Report Packet 4A Report Reference Altitude Altitude SINGLE Meters above WGS 84 or MSL Reserved SINGLE Reserved Flag BYTE Reserved Acutime 2000 Synchronization Kit User Guide A 49 Trimble Standard Interface Protocol A A 50 The Single Precision LLA Position Fix variation of the packet provides current GPS position fix in LLA latitude longitude and altitude coordinates If the I O position option is set to LLA and the I O precision of position output is set to single precision and the packet is masked with packet 8E 4D then the receiver sends this packet each time a fix is computed The data format is shown below Table A 40 Report Packet 4A Report Single Precision LLA Position Latitude SINGLE Radians for north for south Longitude SINGLE Radi
62. max D 3 Specifications and Drawings D Table D 5 Serial Protocols Interface Protocols Defaults TxB primary RS 422 485 or TSIP NMEA TSIP 9600 RS 232 8 odd 1 RxB primary RS 422 485 or TSIP TSIP 9600 RS 232 8 odd 1 TxA secondary RS 422 485 or TSIP TSIP 9600 RS 232 8 odd 1 RxA secondary RS 422 485 or Event RTCM Event Input RS 232 All ports support baud rates of 300 38 400 8 data bits even odd no parity NMEA messages ZDA default Available messages GGA GLL VTG GSV GSA ZDA RMC D Specifications and Drawings D 2 Acutime 2000 Standard Interface Cable Diagram Figure D 1 provides a technical drawing of the Acutime 2000 standard interface cable D 5 Specifications and Drawings Paired Paired Paired Paired Paired Paired Power Ground Receive Receive Transmit transmit RTCM In RTCM In VBackup VFlash 1 PPS 1 PPS 50 6 L 1 60 1 REF Wires Signal RS422 Signal RS232 Power round Receive B CTS Transmit B Receive A Transmit A VBackup VFlash ignal Gnd 1 PPS _ 4 0 Part Number Rev Level Label 1 Red 9 Black ly 10 Blue Orange Wht 12 Black Wht Drain Wires NC NC Figure D 1 Acutime 2000 Standard Interface Cable D 6 Specifications and Drawings NOTES 1 PRODUCT SHOULD BE FULLY ASSEMBLED AND ELECT
63. mm yy Magnetic variation in degrees E East W West Checksum Mandatory for RMC Acutime 2000 Synchronization Kit User Guide C 9 NMEA 0183 C C 4 6 VTG Track Made Good and Ground Speed The VTG message conveys the actual track made good COG and the speed relative to the ground SOG SGP VTIG x x T x x M x x N x x K hh lt CR gt lt LF gt Table C 8 VTG Track Made Good and Ground Speed Message Parameters Field Description 1 Track made good in degrees true 2 Track made good in degrees magnetic 3 4 Speed over the ground SOG in knots Speed over the ground SOG in kilometer per hour hh Checksum C 10 Acutime 2000 Synchronization Kit User Guide C NMEA 0183 C 4 7 ZDA Time amp Date The ZDA message contains UTC the day the month the year and the local time zone SGP ZDA hhmmss S XX XX XXXX hh lt CR gt lt LF gt Table C 9 ZDA Time 8 Date Message Parameters Description UTC Day 01 to 31 Month 01 to 12 Year unused unused Checksum DX Note Fields 5 and 6 are null fields in the Acutime 2000 output A GPS receiver cannot independently identify the local time zone offsets w Caution If UTC offset is not available time output will be in GPS time DX Note GPS time can be used as a time tag for the 1 PPS The ZDA message comes out 100 500 msec after the PPS Acutime 2000 Synchronization Kit U
64. mode and lists the satellites used for navigation and the DOP values of the position solution SGP GSA a X XX XX XX XX XX XX XX XX XX XX XX XX X X X X X x hh lt CR gt lt LF gt Table C 5 GSA GPS DOP and Active Satellites Message Parameters Field Description 1 Mode M Manual A Automatic In manual mode the receiver is forced to operate in either 2D or 3D mode In automatic mode the receiver is allowed to switch between 2D and 3D modes subject to the PDOP and satellite masks Current Mode 1 fix not available 2 2D 3 3D PRN numbers of the satellites used in the position solution When less than 12 satellites are used the unused fields are null Position dilution of precision PDOP Horizontal dilution of precision HDOP Vertical dilution of precision VDOP Checksum Acutime 2000 Synchronization Kit User Guide C 7 NMEA 0183 C 8 C 4 4 GSV GPS Satellites in View The GSV message identifies the GPS satellites in view including their PRN number elevation azimuth and SNR value Each message contains data for four satellites Second and third messages are sent when more than four satellites are in view Fields 1 and 2 indicate the total number of messages being sent and the number of each message respectively SGP GSV X X XX XX XX XXX XX XX XX XXX XX XX XX XXX XX XX XX XXX XX hh lt CR gt lt LF gt Table C 6 GSV GPS Satellites
65. most recent measurement then it is projected to this time The difference is that the fix will have more latency than a fix provided with the above timing option This is the best choice for users performing non real time error analysis or non real time DGPS solution space corrections This is also the preferable mode for users integrating GPS with other sensors where communication lags are the dominant latencies and thus the time lag between the applicability and availability of the fix is small Byte 3 Byte 3 the auxiliary byte controls the output of additional fix data It contains two control bits s Bit 0 controls the output of raw measurements Packet 5A Bit 1 controls whether the raw measurements output in packet 5A are doppler smoothed A 34 Acutime 2000 Synchronization Kit User Guide 0x37 0x38 Trimble Standard Interface Protocol Command Packet 37 Last Position and Velocity Request This packet requests information regarding the last position fix The GPS receiver returns packet 57 and the appropriate position packet 42 or 4A or 83 or 84 and the appropriate velocity packet 43 or 56 based on the I O options in effect In timing mode the GPS receiver returns packets 57 and 54 Command Packet 38 Download and UpLoad Satellite System Data This packet requests current satellite data almanac ephemeris etc or permits loading initialization data from an external source for example by extracting initia
66. o oo o e e e e a xxiii Cautions and Notes XXIV 1 Introduction JS O A ss oc A Bee ke oe oA he ies Bp ot es 1 1 1 2 Acutime 2000 GPS Smart Antenna Features 1 2 k3 Starter Kit i ae a8 eet do BG e ee a a ee ea a 1 4 2 Getting Started 2 1 Connecting the Smart Antenna o 2 2 2 2 Connecting the Computer and Power Source 2 3 2 3 Communicating with the Acutime 2000 2 4 Acutime 2000 Synchronization Kit User Guide Contents 3 vi Acutime 2000 Installation 3 1 Choosing a Location o e e 3 2 3 2 Mounting the Smart Antenna 3 4 3 3 Routing and Securing the Interface Cable 3 5 3 4 Connecting the Host System 3 6 Acutime 2000 Connections 4 1 Interface and Power Connections 4 2 42 Interface Cables and CommectorS 4 4 4 2 1 Pi OUS ss a AG be es Bt She 4 5 4 3 Connection Instructions 0 00002 ae 4 7 4 3 1 Power Connection Red and Black Wires 4 7 4 3 2 Timing Pulse Connections 4 7 4 3 3 Serial Port Connections 0 4 8 4 3 4 Event Inputs 5s sg20 a2 os e eA eo 4 9 System Operation Sut StartUp si tet Beek bre Medic A the Pk ce ach Ans 5 1 5 2 Automatic Operati0d o e 5 2 5 2 1 Satellite Masks o o 5 2 5 2 2 Tracking Modes o e e
67. pcan a Gea oe a beeen ect ea A 57 Report Packet58 o A 58 Report Packet 58 ALMANAC Data Report A 59 Report Packet 58 ALMANAC HEALTH Data Report A 60 Report Packet 58 IONOSPHERE Data Report A 60 Report Packet 58 UTC Data Report A 61 Report Packet 58 EPHEMERIS Data Report A 61 Report Packet59 0 o o A 63 Report Packet SAT ol a at aS A 64 Report Packet SB one arc rr E Bod A 67 Report Packet5C 0 o o o o A 68 Report Packet 5F 11 EEPROM Segment Status Report A 70 Report Packet 0x60 Data Formats A 71 Report Packet 0x60 Data Formats for Health and Power A 72 Command Packet 0x61 Data Formats A 73 Report Packet 6D oss secs ee ead eR Ase Ge od aa A 74 Command Packet TA o o o o A 75 Report Packet 835 dit gee A A ae a A A 76 Report Packet 84 023s he sn iaa oa arate dog eee ak Ss A 77 Survey State Configurations A 78 Vaild GPS Configuration Settings A 79 Command Packet BB o o A 81 Command Packet BC o oo A 83 Acutime 2000 Synchronization Kit User Guide XV List of Tables Table A 71 Table A 72 Table A 73 Table A 74 Table A 75 Table A 76 Table A 77 Table A 78 Table A 79 Table A 80 Table A 81 Table A 82 Table A 83 Table A 84 Table A 85 Table A 86 Table A 87 Table A 88 Table A
68. refclock_ioctl fd 9 flags 20 peer_configt 127 127 29 0 mode 3 vers 4 min 5 max 10 flags Ox00a1 ttl key 0 resolving terrapin trimble com resolving ig trimble com loop_configt state 2 freq 40 642 report_event system event event_restart 0x01 status sync_alarm sync_unspe c 1 event event_unspec 0xc010 gt auth_agekeys at 1 keys 1 expired 0 key_expire_all at 1 private f9bcd099 peer_config 155 63 31 220 mode 3 vers 4 min 6 max 10 flags 0x0001 ttl 0 key 0 peer_config 155 63 32 173 mode 3 vers 4 min 6 max 10 flags 0x0001 ttl key 0 refclock_transmit at 18 127 127 29 0 palisade_poll unit 9 polling event palisade_receivet unit 0 1999 131 06325336 981446 palisade_receivet unit 0 bae24be0 fc549b62 Mon May 10 1999 23 25 36 985 refclock_receivet at 18 127 127 29 0 peer GPS_PALISADE O event event_reach 0x84 status unreach conf 1 event event_reach 0x8014 refclock_sample offset 0 004220 disp 0 000000 std 0 000000 clock_filter offset 0 004220 delay 0 000000 disp 7 937502 std 0 003947 age 0 transmit at 19 to 155 63 31 220 mode 3 transmit at 19 to 155 63 32 173 mode 3 receive at 19 from 155 63 31 220 mode 4 pkt_mode 4 action 1 peer 155 63 31 220 event event_reach 0x84 status unreach conf 1 event ev ent_reach 0x8014 gt clock_filter offset 0 006652 delay 0 002852 disp 7 937510 std 0 006222 age 0 receive at 19 from 155 63 32 173 mode 4 pkt_mode 4 action 1 peer 155
69. shown below Table A 65 Report Packet 83 DOUBLE meters DOUBLE meters DOUBLE meters clock bias DOUBLE meters time of fix SINGLE seconds The time of fix is in GPS time or UTC as selected by the I O timing option in packet 0x35 At start up if the I O double precision option is selected this packet is also sent with a negative time of fix to report the current stored position Packet 42 provides a single precision version of this information Acutime 2000 Synchronization Kit User Guide 0x84 Trimble Standard Interface Protocol Report Packet 84 Double precision LLA Position Fix and Bias Information This packet provides current GPS position fix in LLA coordinates If the I O position option is set to LLA and the double precision option is selected packet 35 the receiver sends this packet each time a fix is computed The data format is shown in the table below Table A 66 Report Packet 84 latitude DOUBLE radians Hor north for south longitude DOUBLE radians Hor east for west altitude DOUBLE meters clock bias DOUBLE meters time of fix SINGLE seconds The time of fix is in GPS time or UTC as selected by the I O timing option packet 35 At start up this packet is also sent with a negative time of fix to report the current stored position Packet 4A provides a single precision version of this information Caution When conver
70. stratum 3 precision 20 rootdelay 6 917 rootdispersion 95 273 peer 35601 refid homer Trimble COM reftime bae2553d 5b0f27bb Tue May 11 1999 0 05 33 355 poll 6 clock bae25559 phase 583 564 ntpq gt ntpq gt ntpg gt a0cd5304 Tue May 11 1999 0 06 01 628 state 1 Frequency 58 680 jitter 85 053 stability 75 934 Acutime 2000 Synchronization Kit User Guide 6 37 NTP Software Installation and Configuration 6 The reach count for GPS_ACUTIME is 0 which indicates a clock or communication failure Observe also that the status reports sync_ntp and that refid is no longer GPS indicating the server has fallen back to an available network time source For more information on correcting this condition see Appendix E 6 38 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol The Trimble Standard Interface Protocol TSIP provides commands that the system designer can use to configure a GPS receiver for optimum performance in a variety of applications TSIP enables the system designer to customize the configuration of a GPS module to meet the requirements of a specific application TSIP is a simple bidirectional binary packet protocol used in a wide variety of Trimble GPS receivers TSIP offers a broad range of command packets and report packets that provide the GPS user with maximum control over the Acutime 2000 and ACE UTC receivers This appendix provides the information neede
71. 0 Synchronization Kit User Guide 3 Acutime 2000 Installation 3 3 Routing and Securing the Interface Cable After the smart antenna is mounted 1 Route the interface cable from the smart antenna to the host location bX Note The interface cable is a digital cable so it can be spliced and extended if necessary Choose the most direct path to the host system while avoiding the following hazards sharp bends or kinks in the cable e hot surfaces exhaust manifolds or stacks e rotating or reciprocating equipment e sharp or abrasive surfaces door and window jambs e corrosive fluids or gases 2 When you have established the ideal cable routing secure the cable along the routing using tie wraps When securing the cable start at the antenna and work towards the host system To provide strain relief for the interface cable connections ensure that the cable is secured at points close to the smart antenna and the host system bX Note Additional protection for example heat shrink tubing may be required to protect the cable jacket at points where the cable enters or exits bulkheads especially if the opening is rough or sharp 3 Once the cable is secured the host end of the cable can be cut to an appropriate length if necessary Leave enough slack to allow for easy connection to the host and normal movement for example rack gimbal or swivel mounts Acutime 2000 Synchronization Kit User Guide 3 5
72. 0 Synchronization Kit User Guide A Table A 101 Datums Continued A axis 6378160 0 Trimble Standard Interface Protocol Eccentricity 0 00669454185459 Description S American 1969 Peru 6378160 0 0 00669454185459 S American 1969 Trin Tob 6378160 0 0 00669454185459 S American 1969 Venezuela 6378155 0 0 00669342162297 South Asia 6378388 0 0 00672267002233 Southeast Base 6378388 0 0 00672267002233 Southwest Base 6377276 345 0 00663784663020 Timbalai 1948 6377397 16 0 00667437223180 Tokyo Mean 6377397 16 0 00667437223180 Tokyo Korea 6377397 16 0 00667437223180 Tokyo Okinawa 6378388 0 0 00672267002233 Tristan Astro 1968 6378249 15 0 00680351128285 PViti Levu 1916 6378270 0 0 00672267002233 Wake Eniwetok 6378388 0 0 00672267002233 Zanderij 6377397 16 0 00667437223180 Bukit Rimpah 6378388 0 0 00672267002233 Camp Area Astro 6377397 16 0 00667437223180 Gunung Segara 6378388 0 0 00672267002233 Herat North 6378388 0 0 00672267002233 Hu Tzu Shan 6378388 0 0 00672267002233 Tananarive Observ 1925 6378388 0 0 00672267002233 Yacare 6377397 155 Acutime 2000 Synchronization Kit User Guide 0 00667437223180 Tokyo GS
73. 267002233 Description Hong Kong 1963 6377276 345 0 00663784663020 Indian Thai Viet 6377301 243 0 00663784663020 Indian India Nepal 6377340 189 0 00667053999999 Flreland 1965 6378388 000 0 00672267002233 FISTS 073 Astro 1969 6378388 000 0 00672267002233 Johnston Island 1961 6377276 345 0 00663784663020 Kandawala 6378388 000 0 00672267002233 Kerguelen Island 6377304 063 0 00663784663020 Kertau 1948 6378388 000 0 00672267002233 La Reunion 6378206 400 0 00676865799761 L C 5 Astro 6378249 145 0 00680351128285 Liberia 1964 6378206 400 0 00676865799761 Luzon Phillippines 6378206 400 0 00676865799761 Luzon Mindanao 6378249 145 0 00680351128285 Mahe 1971 6378388 000 0 00672267002233 Marco Astro 6377397 155 0 00667437223180 Massawa 6378249 145 0 00680351128285 Merchich 6378388 000 0 00672267002233 Midway Astro 1961 6378249 145 0 00680351128285 Minna 6378249 145 0 00680351128285 Nahrwan Masirah 6378249 145 0 00680351128285 Nahrwan UAE 6378249 145 0 00680351128285 Nahrwan Saudia 6377483 865 0 00667437223180 Namibia 6378388 000 0 00672267002233 Naparima 6378206 400 Acutime 2000 Sync
74. 27 29 1 clock GPS_PALISADE 1 event clk_noreply 0x01 da unit 1 polling event The last two lines of output on this screen show the Acutime NTP driver reporting failure to receive a time stamp from the GPS These messages indicate that NTP is not receiving data from the reference clock Acutime 2000 Synchronization Kit User Guide E 11 NTP Diagnostics and Debugging E Table E 1 shows troubleshooting options Table E 1 Troubleshooting Acutime is Not Responding Possible Problem Solution Cabling or connectors have become Connect and secure loose or detached disconnected cables and connectors System does not support event Configure fallback to synchronous polling polling mode Update NTP software No activity of Power or PPS indicators Confirm availability of wall power Use a on the Acutime Synchronization monitoring utility on Port B to check GPS Interface Module status GPS is not tracking satellites Receiver may be jammed or obscured The Acutime NTP driver will not Use a TSIP monitoring utility on Port B to accept time stamps from the GPS check GPS health and status Verify that receiver if it is not tracking satellites adequate power is being supplied to the receiver If none of these options solve the problem check your operating system error log for failure reports E 2 4 Running NTP with Event Polling Disabled The Acutime NTP reference clock can be operated without event polling
75. 3 ere tom 4 7 Y Single meters 8 11 Z Single meters Command Packet 24 GPS Receiver Position Fix Mode Request This packet requests the current position fix mode of the GPS receiver This packet contains no data The GPS receiver returns packet 6D Command Packet 25 Initiate Soft Reset Self Test Command This packet commands the GPS receiver to perform a software reset The GPS receiver performs a self test as part of the reset operation This packet contains no data Following completion of the reset the receiver outputs the startup messages see Table A 1 The receiver retains the time survey position port configuration and almanac contents during this operation Note The GPS receiver sends packet 45 only on power up and reset or on request If packet 45 appears unrequested either the GPS receiver power was cycled or the GPS receiver was reset Command Packet 26 Health Request This packet requests health and status information from the GPS receiver This packet contains no data The GPS receiver returns packets 46 and 4B Acutime 2000 Synchronization Kit User Guide A 23 Trimble Standard Interface Protocol A 0x27 0x28 0x29 0x2A A 24 Command Packet 27 Signal Levels Request This packet requests signal levels for all satellites currently being tracked This packet contains no data The GPS receiver returns packet 47 Command Packet 28 GPS System Message Request This packet reques
76. 3 Report Packets Sent by the GPS Receiver to the User Table A 15 summarizes the packets output by the receiver It includes the output packet ID a short description of each packet and the associated input packet In some cases the response packets depend on user selected options These selections are covered in the packet descriptions beginning on page A 20 Table A 15 Report Packets Sent by GPS Receiver to User Output ID Packet Description Timing port configuration Almanac data for one satellite GPS time Single precision XYZ ECEF position Velocity fix XYZ ECEF Software version information Health of receiver Signal level for all satellites GPS system message Almanac health for all sats Single precision LLA position Machine code status Report operating parameters Oscillator offset Response to set GPS time UTC parameters A 16 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Table A 15 Report Packets Sent by GPS Receiver to User Continued Output ID Packet Description One satellite bias and bias rate 22 I O options 35 Velocity fix ENU 37 Information about last computed fix 37 GPS system data acknowledge 38 Satellite enable disable and health heed ignore 39 Raw measurement data 3A Satellite ephemeris status 3B Satellite tracking status 3C Request EEPROM segment status All in view satellite selection 24 NMEA interva
77. 63 32 173 event event_reach 0x84 status unreach conf 1 event ev ent_reach 0x8014 gt ieee offset 0 005882 delay 0 002414 disp 7 937506 std 0 005502 age 0 Acutime 2000 Synchronization Kit User Guide E 9 NTP Diagnostics and Debugging E The Acutime NTP reference clock driver reports requests and receipt of the time stamp data Typical Acutime NTP time transfer debug output appears as four lines in the debug output as shown here Palisade poll unit 0 polling event Palisade_ receive unit 0 1999 131 06 25 36 981446 Palisade receive unit 0 bae24be0 fc549b62 Mon May 10 1999 23 25 36 985 refclock_receive at 18 127 127 29 0 The Acutime driver reports the GPS time stamp in the first Acutime_receive line The second line reports the local NTP and system time associated with the time transfer event The third line discloses the source identifier prefix and unit number of the time source Note The Acutime_poll message may not be immediately succeeded by a Acutime_receive event Acutime 2000 Synchronization Kit User Guide E NTP Diagnostics and Debugging E 2 3 Acutime is not Responding If the Acutime smart antenna is not responding to polls the following output is generated in the debug stream 4 xterm al x lucky_first ntpd d create_sockets 123 bind gt fd 5 family 2 port 123 addr 0 0 0 0 flags 1 bind fd 6 family 2 port 123 addr 127 0 0 1 flags 0 bind fd 7 family 2 port 123
78. 63 32 173 mode 4 pkt_mode 4 action 1 peer 155 63 32 173 event event_reach 0x84 status unreach conf 1 event ev ent_reach 0x8014 ind offset 0 005417 delay 0 004297 disp 7 937506 std 0 005067 age 0 The seconds value reported by the Acutime NTP reference clock is always an integer since the synchronous packets are always transmitted at the beginning of the second Acutime 2000 Synchronization Kit User Guide E NTP Diagnostics and Debugging After confirming functionality of NTP using synchronous packets you can remove fudge flag2 from the configuration file and restart NTPD in debug mode to observe event polling receive events E 2 5 Incorrect Port and Bad Data Ifthe Acutime NTP driver detects invalid packet data on the serial line it generates debug messages similar to the following Run NTP in a higher level debug mode to observe this message ntpd d d clock GPS_Palisade 1 event clk_badformat 0x02 TSIP_decode unit 1 bad packet 6d 4d event 0 len 21 clock GPS_Palisade 1 event clk_badformat 0x02 TSIP_decode unit 1 bad packet 82 02 event 0 len 1 clock GPS_Palisade 1 event clk_badformat 0x02 TSIP_decode unit 1 bad packet 46 00 event 0 len 2 clock GPS_Palisade 1 event clk_badformat 0x02 TSIP_decode unit 1 bad packet 4b 5b event 0 len 3 clock GPS_Palisade 1 event clk_badformat 0x02 TSIP_decode unit 1 bad packet 54 48 event 0
79. 80351128285 Arc 1950 Zaire 6378249 145 0 00680351128285 Arc 1950 Zambia 6378249 145 0 00680351128285 Arc 1950 Zimbabwe 6378249 145 0 00680351128285 Arc 1960 Mean 6378249 145 0 00680351128285 Arc 1960 Kenya 6378249 145 0 00680351128285 Arc 1960 Tanzania 6378388 000 0 00672267002233 Ascension Isl 1958 6378388 000 0 00672267002233 Astro Beacon E 1945 6378388 000 0 00672267002233 Astro B4 Sorol Atoll 6378388 000 0 00672267002233 Astro Dos 71 4 6378388 000 0 00672267002233 Astro Station 1952 6378160 000 0 00669454185459 Australian Geo 1966 6378388 000 0 00672267002233 Bellevue IGN 6378206 400 0 00676865799761 Bermuda 1957 6378388 000 0 00672267002233 Bogota Observatory 6378388 000 0 00672267002233 Compo Inchauspe 6378388 000 0 00672267002233 Canton Island 1966 6378249 145 0 00680351128285 Cape 6378206 400 Acutime 2000 Synchronization Kit User Guide 0 00676865799761 Cape Canaveral mean A 127 Trimble Standard Interface Protocol Table A 101 Datums Continued A axis 6378249 145 Eccentricity 0 00680351128285 Description Carthage 6378388 000 0 00672267002233 Chatham 1971 6378388 000 0 00672267002233 Chua
80. A 29 Report Packet 40 satellite BYTE identification number T_zc SINGLE seconds week number INTEGER weeks eccentricity SINGLE dimensionless T_oa SINGLE seconds io SINGLE radians OMEGA dot SINGLE radians second A 40 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Table A 29 Report Packet 40 square_root_A SINGLE meters OMEGA_0 SINGLE radians omega SINGLE radians M_0 SINGLE radians T_zc is normally positive If no almanac data is available for this satellite then T_zc is negative T_zc and the week number in this packet refer to the Z count time and week number at the time the almanac was received The remaining items are described in the ICD GPS 200 0x41 Report Packet 41 GPS Time Report This packet provides the current GPS time of week and the week number The GPS receiver sends this packet in response to packet 21 and during an update cycle Update cycles occur approximately every 15 seconds when not doing fixes and occur approximately every 150 seconds when doing fixes The data format is shown below Table A 30 Report Packet 41 0 3 GPS time of week SINGLE seconds 4 5 GPS week number INTEGER weeks 6 9 GPS UTC offset SINGLE seconds bX Note GPS time differs from UTC by a variable integral number of seconds UTC GPS time GPS UTC offset Acutime 2000 Synchronization Kit User Guide A 41 Trimbl
81. Acutime 2000 Synchronization Kit User Guide Part Number 45005 00 ENG Revision A Trimble April 2001 Corporate Office Trimble Navigation Limited Timing and Synchronization Group 645 North Mary Avenue Post Office Box 3642 Sunnyvale CA 94088 3642 U S A Phone 1 408 481 8940 1 800 545 7762 Fax 1 408 481 7744 www trimble com Support Offices Trimble Navigation Europe Limited Trimble House Meridian Office Park Osborn Way Hook Hampshire RG27 9HX ENGLAND 44 1256 760 150 Fax 44 1256 760 148 Voicemail 44 1256 761 130 Trimble Navigation Singapore PTE Limited 79 Anson Road 05 02 Singapore 079906 SINGAPORE 65 325 5668 Fax 65 225 9989 Voicemail 65 325 5668 Trimble Japan K K Sumitomo Hamamatsu cho Building 10F 1 18 16 Hamamatsu cho Minato ku Tokyo 105 JAPAN 81 3 5472 0880 Fax 81 3 5472 2326 Trimble Navigation Australia Pty Limited P O Box 769 Spring Hill QLD 4004 AUSTRALIA 61 7 3216 0044 Fax 61 7 3216 0088 Copyright and Trademarks O 2001 Trimble Navigation Limited All rights reserved No part of this manual may be copied reproduced translated or reduced to any electronic medium or machine readable form for any use other than with the Acutime 2000 GPS Smart Antenna or Acutime 2000 Synchronization Kit The Sextant logo with Trimble is a trademark of Trimble Navigation Limited registered in the United States Patent and Trademark Office The Glob
82. Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x8F 4D Report Packet 8F 4D Automatic Packet Output Mask This packet provides information on the automatic packets that may be output by the receiver Sent in response to 8E 4D query or set Table A 94 Report Packet 8F 4D exe wom wre weaning Sd 0 Subcode BYTE ID for this sub packet is always 0x4D 1 4 Bit Mask ULONG Bits in the mask enable output packets A 0 in the bit position means that automatic output of the associated packets is disabled a 1 in the bit positions means that the associated packets can be automatically output The following table describes the meaning and packets output by each set bit Table A 95 Report Packet 8F 4D Output When Output Meaning Packets After Decode Almanac data collected from satellite After Decode Ephemeris data collected from satellite After Decode UTC data collected from satellite After Decode lonospheric data collected from satellite After Decode GPS Message After Decode Almanac health page collected from satellite Reserved Reserved New Fix Partial and full fix complete and packet output timer has expired Acutime 2000 Synchronization Kit User Guide A 113 Trimble Standard Interface Protocol A Table A 95 Report Packet 8F 4D Continued Output When Output Meaning Packets 9 Reserved 10 Reserv
83. Astro 6378388 000 0 00672267002233 Corrego Alegre 6377397 155 0 00667437223180 Djakarta Batavia 6378388 000 0 00672267002233 DOS 1968 6378388 000 0 00672267002233 Easter Island 1967 6378388 000 0 00672267002233 Euro 1950 Mean 6378388 000 0 00672267002233 Euro 1950 Cyprus 6378388 000 0 00672267002233 Euro 1950 Egypt 6378388 000 0 00672267002233 Euro 1950 Eng Scot 6378388 000 0 00672267002233 Euro 1950 Eng Ire 6378388 000 0 00672267002233 Euro 1950 Greece 6378388 000 0 00672267002233 Euro 1950 Iran 6378388 000 0 00672267002233 Euro 1950 Sardinia 6378388 000 0 00672267002233 Euro 1950 Sicily 6378388 000 0 00672267002233 Euro 1950 Norway 6378388 000 0 00672267002233 Euro 1950 Port Spain 6378388 000 0 00672267002233 European 1979 6378388 000 0 00672267002233 Gandajika Base 6378388 000 0 00672267002233 Geodetic Datum 1949 6378206 400 0 00676865799761 Guam 1963 6378388 000 0 00672267002233 GUX 1 Astro A 128 6378388 000 0 00672267002233 Hjorsey 1955 Acutime 2000 Synchronization Kit User Guide Table A 101 Datums Continued A axis 6378388 000 Trimble Standard Interface Protocol Eccentricity 0 00672
84. D 2 physical specifications D 1 pin out descriptions 4 5 position accuracy F 6 selective availability F 6 power connection 4 7 PPS output options 5 6 PPS quantization error 5 6 5 7 pre installation check list 6 4 preparation GPS 6 5 host system 6 6 R raw measurement data A 38 re acquisition F 8 reader comment form 5 report packets A 16 routing interface cable 3 5 S satellite acquisition F 3 cold start F 3 garage search strategy F 5 hot start F 5 warm start F 4 satellite masks 5 2 satellite signal levels A 48 scope XIX securing interface cable 3 5 selective availability F 6 self survey mode 5 4 serial communication 5 10 serial port selection screen B 1 serial protocols D 4 SNR mask 5 3 specifications D 1 electrical D 3 environmental D 2 performance D 2 physical D 1 serial protocols D 4 start up 5 1 system architecture F 10 system operation overview 5 1 T technical assistance xxiii technical support 6 4 theory of operation F 1 timing packet serial connection 4 8 timing pulse connections 4 7 Timing Receiver Monitor 2 4 Timing Receiver Monitor screen serial port selection B 1 Timing Receiver Monitor screens main B 2 tips XXIV tracking codes 5 4 Trimble Standard Interface Protocol see TSIP A 1 TSIP F 7 command packets A 14 0x26 Health Request A 23 0x2B Initial Position Latitude Longitude Altitude Command A 26 0x2F UTC Parameters Command A 27 0x3D Timing Port Configuration Command A
85. ECEF origin for the ellipse The fourth parameter is the semi major axis of the ellipse called the a axis and is also in meters The fifth parameter is the eccentricity of the ellipse and is dimensionless w Caution The GPS receiver does not perform an integrity check on the datum values If unusual inputs are used the output will be equally unusual Table A 72 Command Packet 8E 14 Byte Type Value Units Superpacket ID DOUBLE DX meters DOUBLE DY meters DOUBLE DZ meters DOUBLE A axis meters DOUBLE Eccentricity None Squared 0x8E 15 Command Packet 8E 15 Request Current Datum Values This packet contains only the subpacket ID 0x15 The response to this packet is 8F 15 A 88 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x8E 20 gt lt Command Packet 8E 20 Request Last Fix with Extra Information This packet requests packet 8F 20 or marks it for automatic output If only the first byte 20 is sent an 8F 20 report containing the last available fix will be sent immediately If two bytes are sent the packet is marked unmarked for auto report according to the value of the second byte Table A 73 Command Packet 8E 20 Sub packet ID 0x20 Mark for Auto report 0 do not auto report 1 auto report Note Auto report requires that superpacket output is enabled Refer to command packet 35 This packet must also be enabled with packe
86. ES The binary almanac health page and UTC data streams are similar to reports 40 49 and 4F respectively and those reports are preferred To get ionosphere or ephemeris this report must be used A 58 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Table A 50 Report Packet 58 ALMANAC Data Report Meaning 4 t_oa_raw BYTE cf ICD 200 Sec 20 3 3 5 1 2 5 SV_HEALTH BYTE cf ICD 200 Sec 20 3 3 5 1 2 6 9 e SINGLE cf ICD 200 Sec 20 3 3 5 1 2 10 13 t_oa SINGLE cf ICD 200 Sec 20 3 3 5 1 2 14 17 i_o SINGLE cf ICD 200 Sec 20 3 3 5 1 2 18 21 OMEGADOT SINGLE cf ICD 200 Sec 20 3 3 5 1 2 22 25 sqrt_A SINGLE cf ICD 200 Sec 20 3 3 5 1 2 26 29 OMEGA_0 SINGLE cf ICD 200 Sec 20 3 3 5 1 2 30 33 omega SINGLE cf ICD 200 Sec 20 3 3 5 1 2 34 37 M_0 SINGLE cf ICD 200 Sec 20 3 3 5 1 2 38 41 a_f0 SINGLE cf ICD 200 Sec 20 3 3 5 1 2 42 45 a_f1 SINGLE cf ICD 200 Sec 20 3 3 5 1 2 46 49 Axis SINGLE cf ICD 200 Sec 20 3 3 5 1 2 50 53 n SINGLE cf ICD 200 Sec 20 3 3 5 1 2 54 57 OMEGA_n SINGLE cf ICD 200 Sec 20 3 3 5 1 2 58 61 ODOT_n SINGLE cf ICD 200 Sec 20 3 3 5 1 2 62 65 t_zc SINGLE cf ICD 200 Sec 20 3 3 5 1 2 66 67 weeknum INTEGER cf ICD 200 Sec 20 3 3 5 1 2 68 69 wn_oa INTEGER cf ICD 200 Sec 20 3 3 5 1 2 Note All angles are in radians Acutime 2000 Synchronization Kit User
87. FTWARE LICENSE OR U S 25 00 TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW IN NO EVENT SHALL TRIMBLE OR ITS SUPPLIERS BE LIABLE FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES WHATSOEVER UNDER ANY CIRCUMSTANCE OR LEGAL THEORY RELATING IN ANY WAY TO THE PRODUCTS SOFTWARE AND ACCOMPANYING DOCUMENTATION AND MATERIALS INCLUDING WITHOUT LIMITATION DAMAGES FOR LOSS OF BUSINESS PROFITS BUSINESS INTERRUPTION LOSS OF BUSINESS INFORMATION OR ANY OTHER PECUNIARY LOSS REGARDLESS OF WHETHER TRIMBLE HAS BEEN ADVISED OF THE POSSIBILITY OF ANY SUCH LOSS AND REGARDLESS OF THE COURSE OF DEALING WHICH DEVELOPS OR HAS DEVELOPED BETWEEN YOU AND TRIMBLE BECAUSE SOME STATES AND JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES THE ABOVE LIMITATION MAY NOT APPLY TO YOU Notices Class B Statement Notice to Users This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to Part 15 of the FCC rules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communication However there is no guarantee that interference will not occur in a particular installation If this equipment d
88. GGA hhmmss 1111 111 a nnnnn nnn b t uu v v w w M x x M y y zzzz hh lt CR gt lt LF gt Table C 3 GGA GPS Fix Data Message Parameters Description UTC of Position Latitude N North or S South Longitude E East or W West GPS Quality Indicator 0 No GPS 1 GPS 2 DGPS Number of Satellites in Use Horizontal Dilution of Precision HDOP Antenna Altitude in Meters M Meters Geoidal Separation in Meters M Meters Geoidal separation is the difference between the WGS 84 earth ellipsoid and mean sea level Age of Differential GPS Data Time in seconds since the last Type 1 or 9 Update Differential Reference Station ID 0000 to 1023 Checksum Acutime 2000 Synchronization Kit User Guide C 5 NMEA 0183 C C 4 2 GLL Geographic Position Latitude Longitude The GLL message contains the latitude and longitude of the present vessel position the time of the position fix and the status SGP GLL 1111 111 a yyyyy yyy a hhmmss s A hh lt CR gt lt LF gt Table C 4 GLL Geographic Position Latitude Longitude Message Parameters Field Description 1 2 Latitude N North or S South 3 4 Longitude E East or W West 5 UTC of position 6 Status A Valid V Invalid hh Checksum C 6 Acutime 2000 Synchronization Kit User Guide C NMEA 0183 C 4 3 GSA GPS DOP and Active Satellites The GSA messages indicates the GPS receiver s operating
89. Guide A 59 Trimble Standard Interface Protocol A Table A 51 Report Packet 58 ALMANAC HEALTH Data Report Meaning 4 week for health BYTE cf ICD 200 Sec 20 3 3 5 1 3 5 36 SV_health 32 BYTES cf ICD 200 Sec 20 3 3 5 1 3 37 t_oa for health BYTE cf ICD 200 Sec 20 3 3 5 1 3 38 current t_oa BYTE units seconds 2048 39 40 current week INTEGER Table A 52 Report Packet 58 IONOSPHERE Data Report Meaning compact storage of the following info SINGLE cf ICD 200 Sec 20 3 3 5 1 9 SINGLE cf ICD 200 Sec 20 3 3 5 1 9 SINGLE cf ICD 200 Sec 20 3 3 5 1 9 SINGLE cf ICD 200 Sec 20 3 3 5 1 9 SINGLE ICD 200 Sec 20 3 3 5 1 9 SINGLE ICD 200 Sec 20 3 3 5 1 9 SINGLE ICD 200 Sec 20 3 3 5 1 9 SINGLE ICD 200 Sec 20 3 3 5 1 9 A 60 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Table A 53 Report Packet 58 UTC Data Report Meaning compact storage of the following info A_0 DOUBLE cf ICD 200 Sec 20 3 3 5 1 8 A_1 SINGLE cf ICD 200 Sec 20 3 3 5 1 8 delta_t_LS INTEGER cf ICD 200 Sec 20 3 3 5 1 8 t_ot SINGLE cf ICD 200 Sec 20 3 3 5 1 8 WN t INTEGER cf ICD 200 Sec 20 3 3 5 1 8 WN_LSF INTEGER cf ICD 200 Sec 20 3 3 5 1 8 DN INTEGER cf ICD 200 Sec 20 3 3 5 1 8 delta_t_LSF INTEGER cf ICD 200 Sec 20 3 3 5 1 8 Table A 54 Report Packet 58
90. I coords A 133 Trimble Standard Interface Protocol A A 19 Sample TSIP Routines The following sections give sample routines that use command packet 0x1F and report packet 0x 45 for getting software version information from the ACE UTC GPS via COM1 Source code for a working TSIP monitor program is available at www trimble com support files Sending out TSIP command packet 0x1F In general all TSIP packets use the structure TSIPPKT define MAX_RPTBUF 256 typedef struct short ent size of buf unsigned char status TSIP packet format and parse status code TSIP id code buf MAX_RPTBUF command or report string TSIPPKT Communication with the ACE UTC GPS is accomplished through command routines and report routines Each command routine use send_cmd which supplies the DLE stuffing to the command string and sends the command to the serial port using the primitive function sendb A 134 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol All TSIP packet formats take the form lt DLE gt lt ID gt lt Data String Bytes gt lt DLE gt lt ETX gt where lt DLE gt and lt ETX gt are reserved frame characters with values 0x10 and 0x03 respectively and lt D gt is the packet identifier The following routines perform DLE stuffing on a command packet and send it to the ACE UTC GPS define DLE 0x10 define ETX 0x03 define PORT 1 Send a byte to
91. IP RS422 DC Ground Black Ground Port A RS 422 Transmit Blue NMEA TSIP RS422 One PPS Transmit Orange w RS422 White stripe One PPS Transmit Black w White stripe Acutime 2000 Synchronization Kit User Guide 4 5 Acutime 2000 Connections Table 4 3 Signal Description DC Power Wire Color Acutime 2000 RS 232 Cable Pin Out Protocol Acutime 2000 Connector Red 8 to 36V Pin 1 Port B RS 232 Receive Violet TSIP RS232 Pin 2 Not Used Orange Not Used Pin 3 Port B RS 232 Transmit Brown TSIP RS232 Pin 4 Not Used Yellow Not Used Pin 5 Port A RS 232 Receive White Event Input RTCM Pin 6 Port A RS 232 Transmit Gray TSIP RS232 Pin 7 Vback Green Battery Backup Pin 8 DC Ground Black Ground Pin 9 Not Used Blue Not Used Pin 10 One PPS Transmit Orange White RS422 Pin 11 One PPS Transmit X Black White RS422 Pin 12 Note The cable color codes listed in this table apply only if you are using the Trimble interface cable Note Receive and Transmit are with respect to the Acutime 2000 GPS smart antenna The host Transmit should be connected to the Acutime 2000 s Receive and vice versa Note The Acutime 2000 with an RS 232 interface is designed especially for short cable runs usually under 50 feet F
92. O 5 9 99 8 42 50 PM None i 5 9 99 8 42 50 PM None 6 32 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration The first entry in the Application log is the NTP startup message reporting the NTP Version and build date This entry indicates that NTP has started For more information on system log entries generated by NTP see Appendix E NTP Diagnostics and Debugging Event Detail Date SS Byes fords Acutime 2000 Synchronization Kit User Guide 6 33 NTP Software Installation and Configuration 6 6 8 2 UNIX System Log Files In its native UNIX environment NTP uses the host system s system log facilities to send reports to the operating system log files Refer to your specific system s documentation to learn how to check the system log reports Monitor the host s system message log for status messages from the NTP task A sample sequence of log entries generated by the NTPD daemon at startup are shown below May 17 42 27 terrapin ntpd 4032 ntpd 4 0 92h Mon May 14 28 00 PDT 1999 May 17 42 28 terrapin ntpd 4032 precision 25 usec May 3 17 42 28 terrapin ntpd 4032 using kernel phase lock loop 0041 May 3 17 42 28 terrapin ntpd 4032 Acutime 0 fd 8 dev dev Acutime0 Figure 6 4 Sample UNIX Log Entries 6 34 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 8 3 NTPQ The NTP Query Utility NTP includes
93. OM called segments Each segment is identified with a number and contains a group of related parameters To change the parameter values stored in EEPROM send packet 0x8E 26 to direct the Acutime 2000 to save the current parameter values in a specified segment in the EEPROM You can also direct the Acutime 2000 to set the parameter values to their factory default settings with packet 0x8E 45 When a segment is set to its factory defaults the contents of the EEPROM segment are set and the Acutime 2000 configures itself with the default settings In brief to customize the Acutime 2000 operations for your application Configure the Acutime 2000 using TSIP command packets until the desired operation is achieved Use TSIP packet 0x8E 26 to save the settings in non volatile memory EEPROM The new settings will control the Acutime 2000 operations whenever it is reset or power cycled Tables 5 2 through 5 12 list the user configurable parameters by segment number Each table lists the parameter name its factory default value and the TSIP packet that sets or reads the parameter value typically one TSIP packet sets or reads several related parameters Acutime 2000 Synchronization Kit User Guide 5 System Operation Table 5 2 Receiver Configuration segment 2 Parameter Factory default Request Operating dimension 4 Full Position 3D BB BB BB DGPS mode 3 Auto DGPS GPS BB BB BB Dynamics code 1
94. P This section briefly describes the tools and operating system facilities used when monitoring NTP for correct operation For more information of the capabilities of these tools please refer to your Operating System and NTP documentation NTP provides a network accessible management interface that allows the NTP utilities included in the distribution to communicate with different servers The NTP utilities are virtually identical on both UNIX and Windows platforms NTP query is a utility to quickly check the status of NTP servers or clients The use of the NTP Query utility NTPQ EXE is outlined on page 6 35 NTP start up and synchronization events are written into the Operating System Log files The same messages are generated for UNIX and Windows NT although the log interface is different for the two system classes Acutime 2000 Synchronization Kit User Guide 6 31 NTP Software Installation and Configuration 6 6 8 1 NTP Events on Windows NT On Windows NT the Application Event Log is used to record NTP events Event Log Entries Check the Application Event Log for status messages from the NTP task Event log entries generated by the NTP service appear in the event log as shown When reviewing events in the event log begin with the first event and move upwards reviewing events in chronological order Event Viewer Application Log on 11US015WC03 olx Log View Options Help Date Time Source Category Event User Computer
95. Prov S American 1956 Colom A 131 Trimble Standard Interface Protocol Table A 101 Datums Continued A axis 6378388 0 Eccentricity 0 00672267002233 Description Prov S American 1956 Equador 6378388 0 0 00672267002233 Prov S American 1956 Guyana 6378388 0 0 00672267002233 Prov S American 1956 Peru 6378388 0 0 00672267002233 Prov S American 1956 Venez 6378206 4 0 00676865799761 Puerto Rico 6378388 0 0 00672267002233 Quatar National 6378388 0 0 00672267002233 Qornoq 6378388 0 0 00672267002233 Rome 1940 6378388 0 0 00672267002233 Santa Braz 6378388 0 0 00672267002233 Santo DOS 6378388 0 0 00672267002233 Sapper Hill 1943 6378160 0 0 00669454185459 S American 1969 Mean 6378160 0 0 00669454185459 S American 1969 Argentina 6378160 0 0 00669454185459 S American 1969 Bolivia 6378160 0 0 00669454185459 S American 1969 Brazil 6378160 0 0 00669454185459 S American 1969 Chile 6378160 0 0 00669454185459 S American 1969 Colombia 6378160 0 0 00669454185459 S American 1969 Ecuador 6378160 0 0 00669454185459 S American 1969 Guyana A 132 6378160 0 0 00669454185459 S American 1969 Paraguay Acutime 200
96. RICALLY TESTED BEFORE SHIPPING 2 APPLY TRIMBLE NAVIGATION P N REV LEVEL VENDOR ID AND DATE CODE APPROX WHERE SHOWN THE LETTERING MUST BE IN A PERMANENT CONTRASTING COLOR AND SHOULD BE LEGIBLE PIN 10 12 PIN DEUTSCH p628 A RELEASE TO PRODUCTION 9 27 99 APEREZ 9820 B ADDED NOTE 2 e 24 2000 APERE Z 4 1 ES ae 100F T DB25 MALE 1 SERIAL INTERFACE 1 P N_DAT 38 292 BRADY LABEL 8 F 6 1 12 PIN CONN MMP26C 221251 SOCKET CONT 5 4 1 CABLE 6 TWISTED PAIRS W SHLD amp DRAIN WIRE BLK PVC UV STABILIZED JACKET 1 PLASTIC SHELL FOR DB 25 BLACK 3 2 1 D3 25 CONNECTOR MALE SOLDER CUP 1 PARTS LIST El TRIMELE ES NAVIGATION A PEREZ lowe CABLE ASSY PIN OUT EPIN a DEUTSCH FUNCTION SIGNAL PROTOCAL CONDUCTOR DB25 1 POWER DC 24 Y RED 1 2 PORT BRxD RS 422 RECEIVE VIOLET 25 3 PORT ERDI RS 4227RECEIVE ORANGE 13 4 PORT B TxD RS 422 TRANSMIT BROWN 11 5 PORT BrlxDt RS 422 TRANSMITF YELLOW 23 Z PORT ARxD RS 422 RECEIVE WHITE 24 EVENT TRIGGER 7 PORT ARxD RS 4227RECEIVE GRAY 12 EVENT TRIGGER E PORT AiTxD RS 42e7TRANSMIT GREEN O 9 DC GROUND DC GROUND BLACK 17 i BPS RS 422 PPS OWAE 2 12 PPS RS 422 PPS BA
97. Synchronization Kit User Guide A Trimble Standard Interface Protocol The error codes in Byte 1 of packet 46 are encoded into individual bits within the byte The bit positions and their meanings are shown in Table A 36 Table A 36 Report Packet 46 Error Code Meaning if bit value 1 Bit Position 0 LSB Battery back up failed Note 3 1 Signal Processor error Note 1 Alignment error channel or chip 1 Note 1 Alignment error channel or chip 2 Note 1 Excessive reference frequency error Note 2 Unused Unused 2 3 4 Antenna feed line fault Open or Short 5 6 7 Note 1 After this error is detected the bit remains set until the receiver is reset Note 2 This bit is 1 if the last computed reference frequency error indicated that the reference oscillator is out of tolerance Packet 2D requests the oscillator offset and packet 4D returns the oscillator offset to the user Note 3 The Acutime 2000 does not support BB RAM the bit is always set The ACE UTC supports BB RAM indicating BB RAM checksum and the bit reports the state of the BB RAM at system startup Acutime 2000 Synchronization Kit User Guide A 47 Trimble Standard Interface Protocol A 0x47 0x48 A 48 Report Packet 47 Signal Levels for all Satellites Report This packet provides received signal levels for all satellites currently being tracked or on which tracking is being attempted that is above the elevatio
98. TEGER GPS Week Number Number see above 7 8 UTC INTEGER UTC Offset seconds Offset 9 0 Timing Bit Field 0 GPS time Flag 1 UTC time 1 0 Reserved 1 Reserved 2 0 Time is set 1 Time is not set 3 0 Have UTC info 1 No UTC info 10 Seconds BYTE 0 59 60 for UTC leap second event 11 Minutes BYTE 0 59 Minutes of Hour 12 Hours BYTE 0 23 Hour of Day 13 Day of BYTE 1 31 Day of Month Month 14 Month BYTE 1 12 Month of Year 15 16 Year UINTEGER Four digits of Year e g 1999 Acutime 2000 Synchronization Kit User Guide A 117 Trimble Standard Interface Protocol A 0x8F AC Report Packet 8F AC This report packet provides supplemental timing information once per second if enabled with command packet 8E A5 Information regarding position unit status and health and the operational state of the unit is provided This packet can be requested with command packet 8E AC When enabled this packet is transmitted once per second shortly after report packet 8F AB The position sent in report packet 8F AC depends on the Receiver Operating Mode and on self survey activity When a self survey is in progress the position sent is the running average of all of the position fixes collected so far When the self survey ends or whenever the receiver is using a time only operating mode then the position sent is the position the receiver is using to perform time only fixes When the self survey is disabled or otherwise inactive and the re
99. WHERE Host Service Manual y Hy Profiles Help Startup Parameters NTP starts and the Network Time Protocol service status changes to Started Close the Services Applet Manual NTP configuration is complete NTP will start each time the system is booted To verify the correct operation of NTP and the Acutime NTP reference clock follow the instructions in Monitoring NTP page 6 31 Acutime 2000 Synchronization Kit User Guide 6 23 NTP Software Installation and Configuration 6 6 7 UNIX Installation Unix installation must be performed by a user with root or super user privileges on the system The host system is usually configured to start NTP when the system boots so that re synchronization can be established quickly in case of a power or network failure Consult your UNIX system documentation to determine what start up scripts must be modified to load NTP at system boot time Many late Unix distributions contain administration tools that perform automatic installation and configuration of startup system tasks such as NTP 6 24 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 7 1 Create the Configuration File The NTP configuration file NTP CONF should be located in the ETC directory The window below shows a simple configuration file declaring a Acutime NTP reference clock and a network time server in the Trimble COM domain The Acutime NTP ref
100. WHITE 9 INTERFACE PALISADE NTP DO NOT SCALE DRAWING arr me 37653 ui feas none peri Fd FILEL 576535 Figure D 2 NTP Interface Cable Specifications and Drawings D D 8 E 1 gt lt E 1 1 E NTP Diagnostics and Debugging Diagnostics and Debugging This section presents common reports and failure conditions that may occur on Windows NT and UNIX systems and provides suggestions for their possible sources Note Administrators should check the system s log files periodically Failures usually do not occur unexpectedly and can be averted in many cases System Log Entries The system log entries are shown here in a Windows NT context The text contained in the Description field of the Event Detail dialog is the same that would be found in the System Log of a UNIX system Separate descriptions are provided where the log messages differ Acutime 2000 Synchronization Kit User Guide E 1 NTP Diagnostics and Debugging E E 2 Serial Port Acces Report The configuration of the Acutime NTP reference clock is acknowledged by a report of the COM port used by the driver Verify that the correct port is being used by NTP If this message does not appear there has been a failure Refresh the system log to observe additional error messages Event Detail EYES 2 oras The UNIX version of the message reports the serial port devi
101. a NAD 27 North America Others such as WGS 84 model the whole earth Data Communications Equipment The equipment that provides the functions required to establish maintain and terminate a communication connection Any equipment that connects to DTE using an RS 232 or CCITT V 24 standard interface A preset or initial value that is assumed to be the preferred or appropriate selection for most situations The Placer GPS sensor is shipped with factory default configuration settings the settings were determined by Trimble Acutime 2000 Synchronization Kit User Guide Glossary 3 Glossary differential relative positioning dilution of precision DOP Doppler shift earth centered earth fixed ECEF elevation angle Glossary 4 Determination of relative coordinates of two or more receivers which are simultaneously tracking the same satellites Static differential GPS involves determining baseline vectors between pairs of receivers Also see differential GPS A description of the purely geometrical contribution to the uncertainty in a position fix given by the expression DOP SQRT TRACE A A where A A is the design matrix for the instantaneous position solution dependent on satellite receiver geometry The DOP factor depends on the parameters of the position fix solution Standard terms for the GPS application are GDOP Geometric three position coordinates plus clock offset in the solution PDOP Position
102. a network enabled monitoring utility called NTP QUERY This utility has a number of features that enable the user to monitor the performance of all time servers from a single console To learn more about NTPQ please refer to NTP documentation When NTPQ is first started it presents a prompt ntpq gt The user enters pe to request the Peer Status List from the local server ntpq gt pe A table similar to the following one is generated Each entry in the table provides information about a reference clock that NTP is attempting to synchronize with Acutime 2000 Synchronization Kit User Guide 6 35 NTP Software Installation and Configuration 6 NTP is Communicating with the Acutime NTP Reference Clock 3 C WINNT System32 ntpq exe ntpq gt ntpq gt ntpq gt pe remote i poll reach offset USO1SWCO2 homer Trimble C ra Trimble COM spring ENG Trim terrapin Trimbl spring ENG Trim spring ENG Trim 0 0 0 0 4000 00 x155 63 38 190 GPS r 48 526 xGPS_PALISADE 1 GPS i 0 002 ntpq gt ntpq gt ntpq gt ntpq gt ntpq gt ry status O4f4 leap_none sync_uhf_clock 15 events event_peer strat_chg processor 1586 system Linux2 0 30 leap 00 stratum 1 precision 17 rootdelay 0 000 rootdispersion 2 935 peer 48057 refid GPS reftime bae0f470 1e077036 Sun May 9 1999 23 00 16 117 poll 7 clock bae0f4b6 ac232096 Sun May 9 1999 23 01 26 672 state 4 phase 0 000 frequency 8 632 jitter 0 002 stability 0
103. abled Stop Bits 1 C 2 NMEA 0183 Message Format The NMEA 0183 protocol covers a broad array of navigation data This broad array of information is separated into discrete messages which convey a specific set of information The entire protocol encompasses over 50 messages but only a sub set of these messages apply to a GPS receiver like the Acutime 2000 The NMEA message structure is described below SIDMSG D1 D2 D3 D4 Dn CS CR LF gt The signifies the start of a message ID The talker identification is a two letter mnemonic that describes the source of the navigation information The GP identification signifies a GPS source MSG The message identification is a three letter mnemonic that describes the message content and the number and order of the data fields 66 99 Commas serve as delimiters for the data fields C 2 Acutime 2000 Synchronization Kit User Guide C NMEA 0183 Dn Each message contains multiple data fields Dn which are delimited by commas il The asterisk serves as a checksum delimiter CS The checksum field contains two ASCII characters which indicate the hexadecimal value of the checksum CR LF The carriage return CR and line feed LF combination terminate the message NMEA 0183 messages vary in length but each message is limited to 79 characters or less This length limitation excludes the and the CR LF The data field block including delimi
104. acket 5B Satellite PRN number BYTE Time of Collection SINGLE seconds Health BYTE IODE BYTE toe SINGLE seconds Fit Interval Flag BYTE SV Accuracy URA SINGLE meters SV PRN Number is from 1 to 32 representing the satellite PRN number Time of Collection is the GPS time when this ephemeris data was collected from the satellite Health is the 6 bit ephemeris health IODE toe and Fit Interval Flag are as described in ICD GPS 200 SV Accuracy URA is converted to meters from the 4 bit code as described in ICD GPS 200 Acutime 2000 Synchronization Kit User Guide A 67 Trimble Standard Interface Protocol 0x5C Report Packet 5C Satellite Tracking Status Report This packet provides tracking status data for a specified satellite Some of the information is very implementation dependent and is provided mainly for diagnostic purposes The receiver sends this packet in response to packet 3C hex The data format is shown below Table A 58 Byte ltem Byte 0 Satellite PRN number Report Packet 5C Type Units BYTE number 1 32 Value Meaning Byte 1 Channel and slot code BYTE MSB 00000 channel 1 0000 1 channel 2 00010 channel 3 0001 1 channel 4 00100 channel 5 0010 1 channel 6 00110 channel 7 0011 1 channel 8 Bit position within Byte 1 bits 7 MSB 3 channel number beginning with 0 used by all receivers 8 channel receivers 8 channel receivers 8 chan
105. acquisition process the Acutime 2000 outputs periodic TSIP status messages on Port B These status messages confirm that the receiver is working bx Note The Acutime 2000 has no provision for external backup power and always begins operation from a cold start unless a warm start is forced by uploading almanac data and time Acutime 2000 Synchronization Kit User Guide 5 1 System Operation 5 5 2 5 2 5 2 1 Automatic Operation When the Acutime 2000 has acquired and locked onto a set of satellites that pass the mask criteria listed below and has obtained a valid ephemeris for each satellite it performs a self survey After a number of position fixes lasting approximately 40 minutes the self survey is complete At that time the Acutime 2000 automatically switches to a time only mode and periodic outputs of navigation information cease Satellite Masks The Acutime 2000 continuously tracks and uses up to eight satellites in an overdetermined clock solution The satellites must pass the mask criteria to be included in the solution Table 5 1 lists the default satellite masks used by the Acutime 2000 These masks serve as the screening criteria for satellites used in fix computations and ensure that solutions meet a minimum level of accuracy The satellite masks can be adjusted using the TSIP protocol described in Appendix A Trimble Standard Interface Protocol Table 5 1 Default Satellite Mask Settings Setting Elevati
106. act Trimble for custom length cables up to 300 m For a list of part numbers refer to www trimble com products acutime2000 Note The standard interface cables offered by Trimble are not terminated on the host end so the appropriate connector must be installed before connecting the cable to the host system For OEMs and integrators who want to produce their own interface cables Table 4 3 specifies the source and part number of the mating cable connectors for the 12 pin connector Mating Connectors Mating Manufacturer Description Connector MMP Series Deutsch Commercial Products Connector 5733 W Whittier Avenue body Hemet California 92545 requires a Phone 909 765 2200 molded Fax 909 922 1544 backshell Acutime 2000 Synchronization Kit User Guide 4 Acutime 2000 Connections 4 2 1 Pin Outs Table 4 2 lists the pin out descriptions and color codes for the standard interface cables Table 4 2 Acutime 2000 RS 422 Cable Pin Out Signal Description Wire Color Protocol Acutime 2000 Connector DC Power Red 8 to 36 V 8 to 36 Volts DC Port B RS 422 Receive Violet TSIP RS422 Port B RS 422 Receive Orange TSIP RS422 Port B RS 422 Transmit Brown TSIP RS422 Port B RS 422 Transmit Yellow TSIP RS422 Port A RS 422 Receive White Event Input RTCM RS422 Port A RS 422 Receive Gray Event Input RTCM RS422 Port A RS 422 Transmit Green NMEA TS
107. addr 155 63 33 57 flags 1 init_iot maxactivefd 7 refclock_open fd 9 modem status 6 refclock_ioctl fd 9 flags 20 peer_configt 127 127 29 1 mode 3 vers 4 min 5 max 10 flags 0x0021 ttl key 0 resolving terrapin trimble com resolving iq trimble com loop_config state 2 freq 40 642 report_event system event event_restart 0x01 status sync_alarm sync_unspe c 1 event event_unspec 0xc010 auth_agekeys at 1 keys 1 expired 0 key_expire_all at 1 private 3b9d1599 peer_config 155 63 31 220 mode 3 vers 4 min 6 max 10 flags 0x0001 ttl 0 key 0 peer_config 155 63 32 173 mode 3 vers 4 min 6 max 10 flags 0x0001 ttl 0 key 0 receive at 9 from 155 63 31 220 mode 3 pkt_mode 3 action 0 pkt_mode 3 action 2 transmit at 9 to 155 63 31 220 mode 4 refclock_transmit at 18 127 127 29 1 palisade_poll unit 1 polling event transmit at 19 to 155 63 31 220 mode 3 transmit at 19 to 155 63 32 173 mode 3 receive at 19 from 155 63 31 220 mode 4 pkt_mode 4 action 1 peer 155 63 31 220 event event_reach 0x84 status unreach conf 1 event ev ent_reach 0x8014 clock_filter offset 0 004226 delay 0 002572 disp 7 937510 std 0 003953 age 0 receive at 19 from 155 63 32 173 mode 4 pkt_mode 4 action 1 peer 155 63 32 173 event event_reach 0x84 status unreach conf 1 event ev ent_reach 0x8014 clock_filter offset 0 003626 delay 0 002129 disp 7 937506 std 0 003391 age 0 refclock_transmit at 50 127 1
108. and contribute to a lower position accuracy For most applications a PDOP mask of 8 offers a satisfactory trade off between accuracy and GPS coverage With worldwide GPS coverage the PDOP mask can be lowered even more for many applications without sacrificing coverage bX Note PDOP is only applicable during self survey or whenever the receiver is performing position fixes Acutime 2000 Synchronization Kit User Guide 5 3 System Operation 5 5 2 2 Tracking Modes The Acutime 2000 operates in one of two main fix modes Self Survey Position fix mode Overdetermined Clock mode After establishing a reference position in Self Survey mode the Acutime 2000 automatically switches to Overdetermined OD Clock mode Self Survey Mode At power on the Acutime 2000 performs a self survey by averaging 2000 position fixes The number of position fixes until survey completion is configurable using the 8E 4B or 8E A9 command The default mode during self survey is 3 D manual where the receiver must obtain a 3 D solution with a PDOP below both the PDOP mask and PDOP switch The PDOP mask and switch criteria can be set and queried using a TSIP packet If fewer than four conforming satellites are visible the Acutime 2000 suspends data output The highest accuracy fix mode is 3 D manual where altitude is always calculated along with the latitude longitude and time Obtaining a position requires four satellites with a PDOP below the
109. ans for east for west Altitude SINGLE Meters Clock Bias SINGLE Meters Time of Fix SINGLE Seconds The LLA conversion is done according to the datum selected using packet 8E 14 The default is WGS 84 Altitude is referred to the WGS 84 ellipsoid or the MSL Geoid depending on which I O LLA altitude option is selected The time of fix is in GPS time or UTC depending on which I O timing option is selected This packet also is sent at start up with a negative time of fix to report the current stored position Packet 84 provides a double precision version of this information Caution When converting from radians to degrees significant and readily visible errors will be introduced by use of an insufficiently precise approximation for the constant 7 Pi The value of the constant Pi as specified in ICD GPS 200 is 3 1415926535898 The MSL option is only valid with the WGS 84 datum When using other datums only the HAE option is valid Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x4B Report Packet 4B Machine Code ID and Additional Status Report The receiver transmits this packet in response to packets 25 and 26 and following a change in state This packet identifies the receiver and may present error messages Packet 46 is always sent with this packet The machine ID can be used by equipment communicating with the receiver to determine the type of receiver to which the
110. are corrected to a common master clock Therefore the relative clock error is the same regardless of which satellites are used For synchronization applications requiring a common clock GPS is the ideal solution Acutime 2000 Synchronization Kit User Guide 5 System Operation GPS time accuracy is affected by the same major source of error that affects position accuracy Selective Availability S A The position and time errors are related by the speed of light Therefore a position error of 100 meters corresponds to a time error of approximately 333 nanoseconds The GPS receiver s clocking rate and software affect PPS accuracy The Acutime 2000 s 12 5 MHz clocking rate enables a steering resolution of 80 ns 40 ns Using software algorithms like an overdetermined clock solution the Acutime 2000 mitigates the effects of S A to achieve a PPS accuracy of 50 ns one sigma after survey is complete 5 4 1 Timing Operation The Acutime 2000 automatically outputs a PPS and time tag With an accurate reference position the Acutime 2000 automatically switches to an overdetermined clock mode activates its T RAIM algorithm and outputs a precise PPS The overdetermined clock solution mitigates the effects of S A Using a simple voting scheme based on pseudo range residuals the Acutime 2000 s integrity algorithm automatically removes the worst satellite with the highest residual from the solution set if that satellite s residual is above a
111. atellite masks SA SEP serial communication serial port signal to noise level signal to noise ratio SNR spread spectrum Glossary As satellites approach the horizon their signals can become weak and distorted preventing the receiver from gathering accurate data Satellite masks enable you to establish criteria for using satellite data in a position solution There are three types of satellite masks Elevation SNR and PDOP Selective Availability This is the name of the policy and the implementation scheme by which unauthorized users of GPS will have their accuracy limited to 100 meters 2D RMS horizontal and 156 meters 2D RMS vertical Spherical Error Probability The radius of a sphere such that 50 of the position estimates will fall within the surface of the sphere A system of sending bits of data on a single channel one after the other rather than simultaneously A port in which each bit of information is brought in out on a single channel Serial ports are designed for devices that receive data one bit at a time GPS signals with SNRs that do not meet the mask criteria are considered unusable A measure of the relative power levels of a communication signal and noise on a data line SNR is expressed in decibels dB Signal to Noise Ratio The received GPS signal is a wide bandwidth low power signal 160 dBW This property results from modulating the L band signal with a PRN code in order to s
112. ates at the L1 frequency 1575 42 MHz and processes the Coarse Acquisition C A code portion of the GPS signal The RF and digital signal processing components of the GPS module are custom ASICs designed by Trimble In addition to the signal processing functions these ASICs also contain support circuitry for the microprocessor The microprocessor performs the navigation computations in addition to controlling the DSP channels and managing the I O operations GPS satellite signals are collected by the antenna filtered and amplified by the antenna s pre amp and then fed to the RF down converter A highly stable crystal reference oscillator operating at 12 504 MHz supports the down converter in producing the correct signals for the digital signal processor The signal processing stage tracks the GPS satellite signals and extracts the carrier code information as well as the navigation data at 50 bits per second In addition to supporting the down conversion process the crystal oscillator also serves as the reference clock for the navigation processor This microprocessor controls the operation of the signal processing channels by allocating the channels during satellite acquisition and tracking In the overdetermined mode of operation the smart antenna automatically tracks the highest eight or twelve satellites above the horizon and selects the optimal set of satellites for the position solution In addition to controlling the DSP stage t
113. ats ere on COI ype vane tron Modified Z count UINT16 0 5999 6 SEC 0 6 Number of SVs 0 31 7 Version 2 flag Bit 1 must be set The next 3 bytes are repeated as a group for each satellite 0 4 SV PRN 0 31 0 Is SV 32 5 7 Scale factor 0 Low Scale factor 02m 002 m s 4 High Scale factor 32m 032 m s Correction not usable Range correction UINT16 RTCM 104 The units and scale factors are as defined by Packet 0x60 Delta range correction rates are not entered Acutime 2000 Synchronization Kit User Guide A 73 Trimble Standard Interface Protocol A 0x6D Report Packet 6D All In View Satellite Selection Report This packet provides a list of satellites used for position fixes by the GPS receiver The packet also provides the PDOP HDOP and VDOP of that set and provides the current mode automatic or manual 3 D or 2 D This packet has variable length equal to 16 nsvs minimum 4 where nsvs is the number of satellites used in the solution The GPS receiver sends this packet in response to packet 24 or whenever a new Satellite selection is attempted The GPS receiver attempts a new selection every 30 seconds and whenever satellite availability and tracking status change The data format is shown below Table A 63 Report Packet 6D Bit Value Meaning 0 2 Auto Time Only 1 SV 2D Clock Hold 2D 3D Overdetermined Clock DGPS Reference Auto manual nsvs
114. ay information to clients on the network The network computer is also referred to as the host because it provides a serial interface for the Acutime and processing facilities for time transfer NTP Time Server Requirements The Acutime NTP Synchronization Kit can be used on any Windows NT or UNIX system with an available serial port The NTP software used must include support for the Acutime Smart Antenna Windows NT 4 0 or UNIX System with RS 232 Port NTP Version 4 Executable with Acutime NTP reference clock support As many as four Acutime receivers can be connected to a single time server Optional Equipment DOS Windows 95 98 NT System for monitoring GPS operation through Acutime Port B Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 2 Software Sources and Compatibility The list of systems supporting the Acutime NTP reference clock is continuously growing For updated information see the Trimble web site at www trimble com oem ntp For the latest documentation for the Acutime driver or if Acutime NTP reference clocks are not supported by the version of NTP shipped with your operating system see the Trimble FTP site at ftp ftp trimble com pub ntp You may also be able to obtain binaries supporting Acutime NTP through your operating system vendor s support channel You can also download and compile a late release of the NTP distribution yourself For more informat
115. ble disable and health heed ignore 59 Note 3 Last raw measurement 5A Satellite ephemeris status 5B Tracking status 5C Timing port configuration 3D Request EEPROM segment status Set request NMEA interval and message mask 7B Set receiver configuration BB Set port configuration BC 8F 0B output configuration 8F A5 8F 0B Set new datum 8F 14 Current datum values 8F 15 Last fix fixed point 8F 20 Write receiver configuration EEPROM 8F 26 Manufacturing parameters 8F 41 Production parameters 8F 42 Revert segments to default settings 8F 45 Set request PPS characteristics 8F 4A Survey limit 8F 4B Packet Output Mask 8F 4D Set PPS output option 8F 4E Set PPS Width Acutime 2000 only 8F 4F Set or request packet broadcast mask 8F A5 Issue self survey command 8F A6 Set request primary timing packet 8F AB Set request supplemental timing packet 8F AC 8F AD output configuration 8F A5 8F AD Note 1 Output is determined by packet 35 settings See Table to determine which messages are output at power up Acutime 2000 Synchronization Kit User Guide A 15 Trimble Standard Interface Protocol A Table A 14 Command Packets Sent to the Receiver Continued Note 2 Entering 1SV mode initiates automatic output of packet 54 Note 3 Not all packet 39 operations have a response See packet 39 description Note 4 Output is determined by packet 35 settings A 1
116. ce used in a message similar to May 3 17 42 28 terrapin ntpd 4032 Acutime 0 fd 8 dev dev Palisade0 For more information on UNIX device names see Set Up Device Links page 6 26 Acutime 2000 Synchronization Kit User Guide E NTP Diagnostics and Debugging E 1 2 Error Log Entries The following entries show NTP errors that degrade system operation These failures should be corrected immediately Configuration File Not Found If the Configuration File is not found the following event log entry will be generated On a UNIX system the message will report the file name lt etc ntp conf gt Event Detail Sv Grae Acutime 2000 Synchronization Kit User Guide E 3 NTP Diagnostics and Debugging E bX Note If you are using Windows NT please review Create the Configuration File page 6 17 to ensure the configuration file is named correctly 6 Warning NTP does not stop because of this error Provide a valid configuration file and stop and re start NTP For more information on correcting this error see NTP Configuration File page 6 11 E 4 Acutime 2000 Synchronization Kit User Guide E NTP Diagnostics and Debugging Acutime Configuration Failure An Event Log message that indicates a problem configuring the Acutime NTP reference clock is shown below Event Detail le EYES oras This message is accompanied by additional messages indicating the source of the failure Acutime 2000 Synch
117. ceiver is using a position fix operating mode then the position sent is the position fix computed on the last second Data Fields Receiver Mode This field shows the fix mode that the GPS receiver is currently configured for The ACE UTC GPS spends most of its time in the Overdetermined Clock mode where it uses all available satellites to perform the best time only fix possible See packet OxBB for a description of all available receiver modes Self Survey Progress When a self survey procedure is in progress this field shows the progress of the survey as a percentage of fixes collected so far The self survey will be complete when the self survey progress reaches 100 percent A 118 Acutime 2000 Synchronization Kit User Guide Trimble Standard Interface Protocol Minor Alarms This field is bitwise encoded with several minor alarm indicators A minor alarm indicates a condition that the user should be alerted to but does not indicate an immediate or necessarily any impairment of functionality For each bit a value of 0 means that the condition is not indicated Bits not described below should be ignored Bit 1 Bit 2 Bit 3 Bit 5 Bit 6 Bit 7 Bit 8 Bit 9 Bit 10 Bit 11 Antenna Open ACE UTC only Antenna Short ACE UTC only When 1 indicates that no satellites are yet usable In order for a satellite to be usable it must be tracked long enough to obtain ephemeris and health data When 1 indicates that
118. cf ICD 200 Sec 20 3 3 4 83 86 t_oe SINGLE cf ICD 200 Sec 20 3 3 4 87 90 C_ic SINGLE cf ICD 200 Sec 20 3 3 4 91 98 OMEGA_0 DOUBLE cf ICD 200 Sec 20 3 3 4 99 102 C_is SINGLE cf ICD 200 Sec 20 3 3 4 103 110 io DOUBLE cf ICD 200 Sec 20 3 3 4 111 114 C_rc SINGLE cf ICD 200 Sec 20 3 3 4 115 122 omega DOUBLE cf ICD 200 Sec 20 3 3 4 123 126 OMEGADOT SINGLE cf ICD 200 Sec 20 3 3 4 127 130 IDOT SINGLE cf ICD 200 Sec 20 3 3 4 131 138 Axis DOUBLE sart A 139 146 n DOUBLE derived from delta_n 147 154 rime2 DOUBLE sqrt 1 0 e7 155 162 OMEGA_n DOUBLE derived from OMEGA_0 OMEGADOT 163 170 ODOT_n DOUBLE derived from OMEGADOT Note All angles are in radians A 62 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x59 Report Packet 59 Satellite Attributes Database Report This packet is returned in response to packet 39 if operation mode 3 or 6 is used with packet 39 Normally the GPS receiver selects only healthy satellites based on transmitted values in the ephemeris and almanac which satisfy all mask values for use in the position solution Packet 59 indicates whether each satellite is allowed or not allowed to be selected for use in the position solution or whether each satellite s health is to be heeded or ignored The data format is shown below bX Note When viewing the satellite disabled list the satellites are not
119. cket BC with only Byte 0 Table A 70 above lists the individual fields within the BC report packet A 84 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol A 16 Custom OEM Packets Several packets have been added to the core TSIP protocol to provide additional capability for OEM receivers In OEM packets 8E and their 8F responses the first data byte is a subcode that indicates the superpacket type For example in packet 8E 14 14 is the subcode that indicates the superpacket type Therefore the ID code for OEM packets is 2 bytes long followed by the data A 17 TSIP Superpackets Superpackets describes packets that reduce the I O traffic with the receiver and facilitate interpretation to a modem or data acquisition device with limited programming facilities Acutime 2000 Synchronization Kit User Guide A 85 Trimble Standard Interface Protocol A 0x8E 0B Command Packet 8E 0B Request or Configure Super Packet Output The 8E 0B packet is identical in function to the 8E AD packet If the 8E 0B byte sequence is sent with no data the receiver will return an 8F 0B packet on port 1 The time reported by the 8F 0B packet on port 1 is always the beginning of the current second A 86 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x8E 14 Command Packet 8E 14 Set New Datum This packet allows the user to change the default datum from WGS 84 to one of 180 selected
120. cket Ox8F AB o o A 117 Report Packet 8F AC o o o oo A 121 Report Packet 8F AD o o oo A 123 Tracking Status Flag Definitions A 124 Leap Second Flag Definitions A 125 Acutime 2000 Synchronization Kit User Guide Table A 101 Table C 1 Table C 2 Table C 3 Table C 4 Table C 5 Table C 6 Table C 7 Table C 8 Table C 9 Table D 1 Table D 2 Table D 3 Table D 4 Table D 5 Table E 1 Table E 2 Table F 1 List of Tables Datums ir a A A a a hd AS hee A 126 NMEA 0183 Characteristics o o C 2 Acutime 2000 NMEA Messages C 4 GGA GPS Fix Data Message Parameters C 5 GLL Geographic Position Latitude Longitude Message Parameters 3 goede oe a oe Se et C 6 GSA GPS DOP and Active Satellites Message Parameters C 7 GSV GPS Satellites in View Message Parameters C 8 RMC Recommended Minimum Specific GPS Transit Data Message Parameters o o 000 C 9 VTG Track Made Good and Ground Speed Message Parameters ae and oo de Bd RA i C 10 ZDA Time amp Date Message Parameters C 11 Physical Specifications 000 D 1 Environmental Specifications D 2 Performance Specifications D 2 Electrical Specifications 04 D 3 Serial Protocols 2 03 havea tate al ware Oe NS D 4 Troublesh
121. contained unit with a digital interface the Acutime 2000 eliminates most of the difficulties associated with integrating GPS Once power is applied the Acutime 2000 self initializes acquires satellite signals and computes position and time automatically outputting this data to the host system Acutime 2000 Synchronization Kit User Guide 1 1 Introduction 1 To integrate the Acutime 2000 the OEM only needs to add a standard serial interface port on the host system and develop a software interface Commonly used interface protocols such as NMEA 0183 and the software interface tool the Timing Receiver Monitor simplify this task minimizing the engineering costs associated with integrating the Acutime 2000 1 2 Acutime 2000 GPS Smart Antenna Features The Acutime 2000 has many features common to previous products in the Trimble family of smart antennas including e an 8 to 36 volt DC power supply with protection against reverse polarity Trimble s advanced multi channel GPS receiver architecture including e the reference oscillator e the synthesizer and IF circuits e the digital signal processing hardware e a microprocessor e the serial interface circuitry b a patch GPS antenna with a proprietary pre amp design for excellent performance against jamming signals a sealed waterproof connector supporting both the power and interface connections 1 2 Acutime 2000 Synchronization Kit User Guide Introduction a wa
122. control the choice of the satellite to be used for the 1D Timing mode This packet contains one byte If the byte value is 0 the GPS receiver automatically chooses the usable satellite with the highest elevation above the horizon This automatic selection of the highest satellite is the default action and the GPS receiver does this unless it receives this packet If the byte value is from to 32 the packet specifies the PRN number of the satellite to be used A subsequent value of 0 will return the receiver to automatic 1 SV mode Acutime 2000 Synchronization Kit User Guide A 29 Trimble Standard Interface Protocol A 0x35 A 30 Command Packet 35 1 O Option Flags Command This packet requests the current I O option states and optionally allows the I O option states to be set as desired To request the option states without changing them the user sends the packet with no data bytes included To change any option states the user includes 4 data bytes with the values indicated below in the packet The I O options their default states and the byte values for all possible states are shown below These option states are held in non volatile memory The GPS receiver returns packet 55 Use packet 8E 26 to save settings to EEPROM These abbreviations apply ALT Altitude ECEF Earth centered Earth fixed XYZ Cartesian coordinates LLA Latitude Longitude Altitude HAE Height Above Ellipsoid e WGS 84 Earth model elli
123. d 12 The leading edge of the PPS output pulse is synchronized to UTC The width of the pulse s leading edge is 20 nanoseconds or less The exact width and shape of the pulse depends on the distributed capacitance in the interface cable Acutime 2000 Synchronization Kit User Guide 4 7 Acutime 2000 Connections 4 4 8 For more information on using the timing pulse see Chapter 5 System Operation 4 3 3 Serial Port Connections The recommended use of the serial ports on the Acutime 2000 for most users is as follows Use Port B to configure the Acutime 2000 as necessary Disable the automatic output packets on Port B using command packet 8E A5 Use Port B to transmit the desired timing packet Use Port B to query for specific satellite data as needed Use the Port A receive line to time tag external events or input RTCM data If you have two serial ports use ports A and B on the Acutime 2000 as follows Port B Use Port B to configure the Acutime 2000 as necessary Use Port A to transmit the desired timing packet Use Port B to query for specific satellite data as needed Use the Port A receive line to time tag external events or input RTCM data Port B is the primary serial port for the Acutime 2000 You can send commands receive command replies and query for and receive a variety of satellite data for example ephemeris tracking information signal levels and so on using Port B You can also receive timing pac
124. d set and directs the eight tracking channels in a parallel search for these satellites If the internal oscillator error is known the smart antenna compensates for the offset to optimize the search If the offset is not known the search algorithms are set wide enough to allow for oscillator tolerance aging and temperature errors If the receiver has an almanac and an initial position but does not have the current time it executes a cold start search until the first satellite is acquired Once this first satellite is acquired the receiver can obtain an approximate time and will convert to warm start mode to acquire additional satellites Although the time to first fix is slightly longer in this case it is significantly shorter than a complete cold start The warm start time to first fix is usually less than 50 seconds 40 seconds is typical Acutime 2000 Synchronization Kit User Guide F Theory of Operation F 2 3 Garage Search Strategy During a warm start search the smart antenna knows which satellites to search for based on the system almanac the initial position and the current time In some cases the receiver may not be able to acquire the expected satellite signals for example if the Acutime 2000 is in a jamming environment Trimble s patented garage search strategy also known as a split search is designed for such situations If the receiver does not acquire the expected set of satellites within five minutes of a
125. d to make use of the powerful TSIP features enhance overall system performance and reduce the total development time The reference tables beginning on page A 7 help you determine which packets apply to your application For those applications requiring customization see Table A 12 for a detailed description of the key setup parameters Application guidelines are provided for each TSIP command packet beginning on page A 10 A 1 Interface Scope The Trimble Standard Interface Protocol TSIP is based on the transmission of packets of information between the user equipment host and the GPS receiver Each packet includes an identification code 1 byte representing 2 hexadecimal digits that identifies the Acutime 2000 Synchronization Kit User Guide A 1 Trimble Standard Interface Protocol A A 1 1 meaning and format of the data that follows Each packet begins and ends with control characters Packet Structure TSIP packet structure is the same for both commands and reports The packet format is lt DLE gt lt id gt lt data string bytes gt lt DLE gt lt ETX gt lt DLE gt is the byte 0x10 lt ETX gt is the byte 0x03 and lt id gt is apacket identifier byte which can have any value except for lt ETX gt and lt DLE gt The bytes in the data string can have any value To prevent confusion with the frame sequences lt DLE gt lt id gt and lt DLE gt lt ETX gt every lt DLE gt byte in the data string is preceded by
126. datums or to a user entered custom datum The datum is a set of 5 parameters which describe an ellipsoid to convert the GPS receiver s internal coordinate system of XYZ ECEF into Latitude Longitude and Altitude LLA This will affect all calculations of LLA in packets 4A and 84 and 8F AC and 8F 0B The receiver responds with packet 8F 14 The user may want to change the datum to match coordinates with some other system usually a map Most maps are marked with the datum used and in the US the most popular datum for maps is NAD 27 The user may also want to use a datum that is more optimized for the local shape of the earth in that area However these optimized datums are truly local and will provide very different results when used outside of the area for which they were intended WGS 84 is an excellent general ellipsoid valid around the world To change to one of the internally held datums the packet must contain exactly 2 bytes representing the integer value of the index of the datum desired For a list of the datums and their indexes see Table A 101 Table A 71 Command Packet 8E 14 Superpacket ID 0x14 1 2 INTEGER Datum index Acutime 2000 Synchronization Kit User Guide A 87 Trimble Standard Interface Protocol A Alternatively the unit will accept a 40 byte input packet containing 5 double precision floating point values representing the ellipse The first 3 are DX DY and DZ which represent an offset in meters from the
127. deline For best results mount the antenna below and at least ten feet away from satellite communication equipment For installations exposed to shock or vibration exceeding the limits specified in Appendix D Specifications and Drawings use a mounting scheme that isolates the Acutime 2000 from the excessive shock or vibration Acutime 2000 Synchronization Kit User Guide 3 3 Acutime 2000 Installation 3 3 2 Mounting the Smart Antenna The smart antenna is designed for a pole mount as illustrated in Figure 3 1 The threaded socket in the base of the antenna accepts a standard 1 14 straight thread A wide variety of 1 14 pole mounts are available from marine hardware suppliers After obtaining an appropriate mounting pole follow these simple steps to install the Acutime 2000 GPS smart antenna 1 Secure the mounting pole to a solid structure so that it is oriented vertically 2 Thread the smart antenna onto the pole or pipe and hand tighten until snug w Caution Do not over tighten the smart antenna on the pole or use a tool this could damage the threaded socket in the base of the antenna Also do not use a thread locking compound because it can damage the plastic housing 3 Connect the interface cable to the smart antenna The connector on the interface connector has a locking ring for securing the connection w Caution Do not over tighten the locking ring this can strip the connector 3 4 Acutime 200
128. dix F Theory of Operation gives a more detailed technical description of many of the Acutime 2000 GPS smart antenna s operating characteristics A brief overview of the system architecture is also presented The Glossary contains definitions of GPS and technical terms used in this manual Reader Feedback Your feedback about the product documentation helps us to improve it with each revision To forward your comments do one of the following Send an email to ReaderFeedback trimble com e Complete the Reader Comment Form at the back of this manual and mail or fax it according to the instructions at the bottom of the form If the Reader Comment Form is not available send your comments and suggestions to the address in the front of this manual Please mark it Attention Documentation Group All comments and suggestions become the property of Trimble Navigation Limited Thank you for your help Acutime 2000 Synchronization Kit User Guide xxi About This Manual Related Information The following sections discuss other sources of information that introduce extend or update this manual Update Notes If any changes are made to the firmware update notes and firmware are posted to the Trimble Web site World Wide Web WWW Site For more information about Trimble visit our site on the World Wide Web www trimble com xxii Acutime 2000 Synchronization Kit User Guide About This Manual Technical Assista
129. e amp Triangle logo Trimble and Acutime are trademarks of Trimble Navigation Limited All other trademarks are the property of their respective owners Release Notice This is the April 2001 release Revision A of the Acutime 2000 Synchronization Kit User Guide part number 45005 00 ENG It applies to the Acutime 2000 Synchronization Kit software The following limited warranties give you specific legal rights You may have others which vary from state jurisdiction to state jurisdiction Hardware Limited Warranty Trimble warrants that this Trimble hardware product the Product shall be free from defects in materials and workmanship and will substantially conform to Trimble s applicable published specifications for the Product for a period of one 1 year starting from the date of delivery The warranty set forth in this paragraph shall not apply to software firmware products Software and Firmware License Limited Warranty This Trimble software and or firmware product the Software is licensed and not sold Its use is governed by the provisions of the applicable End User License Agreement EULA if any included with the Software In the absence of a separate EULA included with the Software providing different limited warranty terms exclusions and limitations the following terms and conditions shall apply Trimble warrants that this Trimble Software product will substantially conform to T
130. e A 7 Default Background Packets for Acutime 2000 A 8 Default Automatic Position and Velocity Reports for Acutime 2000 e cio ae eo a Soe eR oe ag A 9 Automatic Primary and Supplemental Timing Reports for ACE UTC 24 2 daca schwag Bae te A 9 Low Latency Timing Packets o A 10 Event Packets 2 0 0 Se EO eee es A 11 Satellite Data Packets o oo A 11 Customizing Receiver Operations A 12 Command Packets Sent to the Receiver A 14 Report Packets Sent by the GPS Receiver to the User A 16 Packet Structure o ee ee A 19 Packet Descriptions o o 00000004 A 20 Custom OEM Packets o e A 85 TSIP Superpackets 2 o o e e A 85 Datums e is oe ee Sad ee ea ee oe A 126 Sample TSIP Routines 2 0 o o A 134 Acutime 2000 Synchronization Kit User Guide Contents B Timing Receiver Monitor Bil Start Up ge ee a ee Pa eae ei B 1 B 2 Main screen o o a B 2 C NMEA 0183 C 1 The NMEA 0183 Communication Interface C 2 C 2 NMEA 0183 Message Format C 2 C 3 NMEA 0183 Message Options C 4 C 4 NMEA 0183 Message Formats o C 5 C 4 1 GGA GPSFixData o o o C 5 C 4 2 GLL Geographic Position Latitude Longitude C 6 C 4 3 GSA GPS DOP and Active Satellites C 7 C 4 4 GSV
131. e As 2x Save in am O El c E File name Itpcont i Save as type an Files Cancel F Save as Unicode 6 18 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration Copying Executable Files The NTP service requires the NTP service executable NTPD EXE to be available at system boot In this example the NTP executable is located in the WINNT SYSTEM32 directory 1 Verify that all required files are present The file sizes and dates may vary but all files must be present for successful installation Yk Command Prompt C ntp gt dir Volume in drive C has no label Volume Serial Number is D845 2F2F Directory of C ntp 02 46p 02 46p a 52p 864 Instsru exe 22p 304 ntpq exe 21p 936 ntpdate exe 22p 400 ntpdc exe 22p 344 ntptrace exe 21p 936 ntpd exe 18p lt DIR gt debug 9 File s 528 384 bytes 9 601 024 bytes free The debug directory contains a debug version of NTP which can be used to obtain more information about system operation or to diagnose problems For more information on using the debug version of NTP refer to Appendix E NTP Diagnostics and Debugging Acutime 2000 Synchronization Kit User Guide 6 19 NTP Software Installation and Configuration 2 Copy NTPQ EXE NTPDATE EXE NTPDC EXE NTPTRACE EXE and NTPD EXE to the WINNT SYSTEM32 directory 5 Command Prompt Volume Serial Number is D845 2F2F Directory of C ntp 46p 46p
132. e Standard Interface Protocol A w Caution GPS week numbers run from 0 to 1023 and then cycles back to week 0 Week 0 began January 6 1980 Another week 0 began August 22 1999 The receiver automatically adds 1024 to the GPS week number after August 21 1999 and reports the cumulative week number The seconds count begins with 0 each Sunday morning at midnight GPS time A negative indicated time of week indicates that time is not yet known in that case the packet is sent only on request The following table shows the relationship between the information in packet 41 and the packet 46 status code Table A 31 Relationship Between Packet 41 and Packet 46 Approximate Time Time Source Packet 0x46 Accuracy Status Code None No time at all 0x01 Unknown Approximate time from 0x01 real time clock or packet 2E 20 to 50 msec clock Time from satellite not 0x01 drift Full accuracy Time from GPS solution 0x00 bX Note Before using the GPS time verify that the packet 46 status code is 0x00 Doing position fixes This ensures the most accurate GPS time A 42 Acutime 2000 Synchronization Kit User Guide 0x42 Trimble Standard Interface Protocol Report Packet 42 Single Precision Position Fix XYZ ECEF Report This packet provides current GPS position fix in XYZ ECEF coordinates If the I O position option is set to XYZ ECEF and the I O precision of position output Packet 35 is set to sin
133. e frequency error of the receiver internal oscillator It is expressed as apparent range rate Time of fix is in GPS or UTC time as selected by the I O timing option in packet 0x35 Caution For accurate interpretation of the propagation delay the precise constant for the speed of light must be used The ICD 200 value for the speed of light is 299 792 458 meters per second Report Packet 55 1 O Option Flags Report This packet provides current I O options in response to packet 35 request The data format is the same as for packet 35 See packet 35 for details Acutime 2000 Synchronization Kit User Guide A 55 Trimble Standard Interface Protocol 0x56 Report Packet 56 Velocity Fix East North Up ENU Report If East North Up ENU coordinates have been selected for the I O velocity option Packet 35 the receiver sends this packet under the following conditions 1 each time that a fix is computed if masked for output by packet 8E 4D 2 in response to packet 37 last known fix The data format is shown in Table A 47 Table A 47 0x56 Velocity Fix East North Up ENU Report East Velocity SINGLE m s for east for west North Velocity SINGLE m s for north for south Up Velocity SINGLE m s for up for down Clock Bias Rate SINGLE m s Time of fix SINGLE seconds The time of fix is in GPS or UTC time as selected by the I O timing optio
134. e smart antenna The connector on the interface connector has a locking ring for securing the connection 2 2 Acutime 2000 Synchronization Kit User Guide 2 Getting Started 2 2 Connecting the Computer and Power Source The connection instructions illustrated in Figure 2 1 assume use of the Trimble interface cable included in the Synchronization Kit If you are using your own cable modify the instructions accordingly Wall Power Acutime 2000 Synchronization Interface Module RS 422 to RS 232 converter PortA Port B Li l im Te Oo primary port Port A Figure 2 1 Connection Diagram Acutime 2000 Synchronization Kit User Guide 2 3 Getting Started 2 2 3 Communicating with the Acutime 2000 When power is applied the Acutime 2000 acquires a valid set of satellites and automatically transmits position and time messages During the satellite acquisition process the Acutime 2000 outputs periodic status messages To begin communicating with the Acutime 2000 start the Timing Receiver Monitor program Data fields in the Timing Receiver Monitor program fill up as the data becomes available For more information see Appendix B Timing Receiver Monitor 2 4 Acutime 2000 Synchronization Kit User Guide 3 Acutime 2000 Installation This chapter provides installation guidelines for the Acutime 2000 GPS smart antenna Installation of the Acutime 2000 requi
135. eceived or repeated due to loss of signal strength the curvature of the earth and the noise introduced because of moisture in the air surrounding the earth s surface The rate of change of range between the satellite and receiver The range to a satellite changes due to satellite and observer motions Range rate is determined by measuring the Doppler shift of the satellite beacon carrier Memory whose contents can be read but not changed Information is placed into ROM only once The contents of ROM are not erased when the system unit s power is turned off The process of determining the vector distance between two points and the coordinates of one spot relative to another This technique yields GPS positions with greater precision than a single point positioning mode can The period during which a satellite is visible i e has an elevation angle that is above the elevation mask A satellite is said to rise when its elevation angle exceeds the mask and set when the elevation drops below the mask Read Only Memory Radio Technical Commission for Maritime Services Commission that recommends standards for differential GPS services RTCM Recommended Standards For Differential GPS Service prepared by RTCM Special Committee No 104 RTCM SC 104 defines a communication protocol for sending GPS differential corrections from a differential reference station to remote GPS receivers Acutime 2000 Synchronization Kit User Guide s
136. ected by each bit Table A 77 Command Packet 8E 4D Packets Affected By Bits Output Default Default When Meaning Output Packets A2K ACE UTC After Decode Almanac data collected from satellite After Decode Ephemeris data collected from satellite After Decode UTC data collected from satellite After Decode lonospheric data collected from satellite After Decode GPS Message After Decode Almanac health page collected from satellite Reserved Reserved Partial and full fix complete and packet output timer has expired Reserved Acutime 2000 Synchronization Kit User Guide A 93 Trimble Standard Interface Protocol Table A 77 Command Packet 8E 4D Packets Affected By Bits Output Packets Default Default ACE UTC Meaning Reserved 6D 46 4B 82 Constellation Change New Fix New satellite selection Reserved Reserved 42 43 4A 54 56 83 84 8F 20 Kinetic and Timing information Output must be enabled using I O options Raw Measurement Data Output must be enabled using I O options New Fix Note 1 A 1 in the bit mask turns on the associated packets and a 0 turns off the output of the associated packets 0x8E 4E Command Packet 8E 4E Set PPS Output Option This command packet sets the PPS driver switch to one of the values listed in Table A 78 The
137. ed 11 6D 82 Constellation New satellite selection Change 12 Reserved 13 29 Reserved 30 4A 8F 20 42 New Fix Dynamic and Timing information 43 54 56 82 Update Output must be enabled with I O 83 84 options 31 5A New Fix Output must be enabled with I O Note 1 options Note 1 A 1 in the bit mask indicates that output for the associated packets is ON a O indicates that the output is turned OFF 0x8F 4E Report Packet 0x8F 4E This report packet is output after the command packet 8E 4E has been executed See the corresponding command packet for information about the data formats 0x8F A5 Report Packet 8F A5 This report packet is output after the command packet 8E A5 has been executed and is identical in structure to packet 8E A5 See the corresponding command packet for information about the data formats A 114 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x8F A6 Report Packet 8F A6 This report packet is output after the command packet 8E A6 has been executed and is identical in structure to packet 8E A6 See the corresponding command packet for information about the data formats Ox8F A9 Report Packet 0x8F A9 This report packet is output after the command packet 8E A9 has been executed and is identical in structure to packet 8E A9 See the corresponding command packet for information about the data formats 0x8F AB Report Packet 8F AB This automatic report
138. ent systems GPS receivers are used to steer a local reference oscillator The steering algorithm combines the short term stability of the oscillator with the long term stability of the GPS PPS An accurate GPS PPS allows the use of cost effective crystal oscillators which have poorer stability than expensive high quality oscillators such as atomic cells The GPS constellation consists of at least 24 orbiting satellites Unlike most telecommunications satellites GPS satellites are not geostationary so satellites in view are constantly changing Each GPS satellite contains four highly stable atomic clocks which are continuously monitored and corrected by the GPS control segment Consequently the GPS constellation can be considered a set of 24 orbiting clocks with worldwide 24 hour coverage A Trimble GPS receiver uses the signals from these GPS clocks to correct its own internal clock which is not as stable or accurate as the GPS atomic clocks A GPS receiver like the Acutime 2000 outputs a highly accurate timing pulse PPS generated by its internal clock which is constantly corrected using the GPS clocks In the case of the Acutime 2000 this timing pulse is synchronized to UTC within 50 nanoseconds one sigma after survey is complete In addition to serving as highly accurate stand alone time sources GPS receivers are used to synchronize distant clocks in communication or data networks This is possible because all GPS satellites
139. er is a unique identification for each of the 32 GPS satellites Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Signal level The Signal Level Byte 5 is a linear approximation of C NO which is stated in antenna amplitude measurement units AMUs a Trimble devised unit Note SNR 43 20log signal counts noise counts BW 2 where signal counts 64 AMU noise counts 90 and BW 1000Hz The C NO is affected by five basic parameters signal strength from the GPS satellite receiver antenna gain pre amplifier noise figure receiver noise bandwidth accumulator sample rate and statistics The approximation is very accurate from 0 to 25 AMUs Codephase The codephase Byte 9 value is the average delay over the sample interval of the received C A code and is measured with respect to the receiver s millisecond timing reference Thus it includes all receiver satellite and propagation biases and errors It is expressed in 1 16th of a C A code chip Doppler The Doppler Byte 13 value is apparent carrier frequency offset averaged over the sample interval It is measured with respect to the nominal GPS Ll frequency of 1575 42 MHz referenced to the receiver s internal oscillator Thus it includes all receiver and satellite clock frequency errors It is expressed in Hertz at the L1 carrier Acutime 2000 Synchronization Kit User Guide A 65 Trimble Standard Interface Pro
140. erence clock is declared as unit 1 A maximum of four Acutime NTP reference clocks can be connected to any UNIX host Valid unit numbers on UNIX systems are 0 3 The next section examines the use of the unit number in mapping to physical serial ports on the host system 4 xterm E lucky_first cat etc ntp conf a CC CC CAC A O SC E Dc AG ES AS A CS E A CL LE DD ERD CS ND A SRD E E cs e e ana UNIX Configuration for Palisade NTP refclock 1 server 127 127 29 1 a Network Time Server server terrapin trimble com A SD a SD a SS Eee eee lucky_first Jj The ETC DRIFT file is used to record information about the onboard system s intrinsic frequency error For more information on this feature please refer to NTP documentation Acutime 2000 Synchronization Kit User Guide 6 25 NTP Software Installation and Configuration 6 6 7 2 E xterm lucky_first lucky_first lucky_first lucky_first lruxruxrux lucky_first lucky_first lruxrwxrwx lruxruxrwx lucky_first lucky_first lucky_first lucky_first lruxruxrwx lruxruxrwx lucky_first lucky_first Set Up Device Links NTP attempts to open the I O file DEV ACUTIMEX to communicate with the Acutime NTP reference clock The x represents the unit number of the reference clock in the configuration file A symbolic link DEV ACUTIMEX must be set up to point to the correct host serial port This is typically performed by a sequence of shell
141. es the information gained from acquiring a specific satellite to eliminate other satellites those below the horizon from the search set This strategy speeds the acquisition of additional satellites required to achieve the first position fix The cold start search sets are established to ensure that at least three satellites are acquired within the first two time out periods As soon as four satellites are acquired the receiver computes an initial position fix The Acutime 2000 typically achieves a cold start in under two minutes A complete system almanac is not required to achieve a first position fix The almanac is used in subsequent warm starts and to aid in acquiring GPS satellites that come into view Acutime 2000 Synchronization Kit User Guide F 3 Theory of Operation F F 2 2 F 4 Warm Start In a warm start condition the receiver has a current almanac an initial position within 3 000 km and current time within five minutes stored in memory Although the smart antenna does not have an onboard battery for preserving memory it can be initialized using the TSIP protocol To force a warm start the almanac time and initial position must be uploaded to the receiver During a warm start the smart antenna identifies the satellites that are expected to be in view given the system almanac the initial position and the time The receiver calculates the elevation and expected Doppler shift for each satellite in this expecte
142. ets the GPS radio navigation signals received by a GPS antenna and determines a location solution The GPS processor may also be able to apply and determine differential GPS corrections The combination of a GPS antenna and a GPS processor The length of the second is fixed and is determined by primary atomic frequency standards Leap seconds are not used as they are in UTC Therefore GPS time and UTC differ by a variable whole number of seconds Horizontal Dilution of Precision The device or instrument connected to the Acutime 2000 smart antenna The host system can be a PC network equipment or timing system depending on the application Hand over word The word in the GPS message that contains time synchronization information for the transfer from C A to P code Acutime 2000 Synchronization Kit User Guide Glossary 7 Glossary interface cable interference integrated Doppler IODE jamming masks maximum PDOP NAVSTAR NMEA NMEA 0183 message Glossary 8 The interface cable allows data to flow between the Acutime 2000 and the communication equipment Refers to the unwanted occurrences on communication channels that are a result of natural or man made noises and signals not properly a part of the signals being transmitted or received A measurement of Doppler shift frequency or phase over time Issue Of Data Ephemeris Part of the navigation data It is the issue number of the ephemeris in
143. eview the GPS satellite message description on the next page Acutime 2000 Synchronization Kit User Guide F 1 Theory of Operation F F 1 GPS Satellite Message Every GPS satellite transmits the Coarse Acquisition C A code and satellite data modulated onto the L1 carrier frequency 1575 42 MHz The C A code is a unique pseudo random sequence for each satellite The satellite data transmitted by each satellite includes a satellite almanac for the entire GPS system its own satellite ephemeris and its own clock correction The satellite data is transmitted in 30 second frames Each frame contains the clock correction and ephemeris for that specific satellite and two pages of the 50 page GPS system almanac The time required to transmit the complete system almanac is 12 5 minutes the time to transmit the satellite ephemeris is 30 seconds The system almanac contains information about each of the satellites in the constellation ionospheric data and special system messages The ephemeris contains detailed orbital information for a specific satellite The GPS system almanac changes infrequently and is typically valid for weeks Ephemeris data changes hourly but is valid for up to four hours The GPS control segment updates the system almanac weekly and the ephemeris hourly through three ground based control stations During normal operation the smart antenna updates the ephemeris stored in its memory at 30 minute intervals The perfor
144. existing time servers use the operating system date time facilities to reset the clock to the approximate local time Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 3 3 Operating System Specific Information This documentation is applicable to Windows NT and UNIX Installation Separate instructions for the different operating systems are provided where required Acutime 2000 Synchronization Kit User Guide 6 7 NTP Software Installation and Configuration 6 6 4 Time Transfer Cable Connection The serial port of the host computer serves as a precision synchronization interface between NTP and the Acutime smart antenna Comnect Port A on the Acutime Synchronization Interface Module to the NTP time server s serial port as shown in Figure 6 1 Trimble provides a standard DB 9 serial cable with the Acutime NTP Synchronization Kit bx Note If your network host s serial port is not a standard DB 9 serial connector you need an appropriate converter Ensure that proper Ground Request To Send Data Transmit and Data Receive connections are supported by the converter Wall Power Synchronization Interface Module PortA PortB Figure 6 1 Time Transfer Connection Diagram 6 8 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 4 1 Optional Connections Port B and the PPS output of the Synchronization
145. f Makefile include Makefile kernel Makefile kernel sys Makefile libntp Makefile libparse Makefile ntpd Makefile ntpde Makefile ntpdate Makefile ntpq Makefile ntptrace Makefile parseutil Makefile scripts ntpver util Makefile config h bash make Acutime 2000 Synchronization Kit User Guide Compiling with GCC now generates lots of new warnings NTP Diagnostics and Debugging Ox NTP installs into the directory USR LOCAL BIN If you wish to install into a different directory please consult the NTP documentation To install NTP into the default directory log in as super user or root and type make install from the NTP 4 XX xX directory NTP Diagnostics and Debugging E E 20 tickadj c 584 warning initialization discards const from pointer target type tickadj ci592 warning initialization discards const from pointer target type tickadj ct593 warning initialization discards const from pointer target type tickadj ct596 warning unused variable kernels tickadj ct In function openfile tickadj c 738 warning declaration of fd shadows global declaration tickadj ct At top level tickadj c 563 warning declaration of fd shadows global declaration tickadj ct In function writevar tickadj ct760 warning declaration of fd shadows global declaration tickadj ct At top level tickadj ct783 warning declaration of fd shadows global declaration tic
146. f the deflection of the vertical at the origin and the geodetic azimuth of a line from the origin to some other point The GPS uses WGS 84 The actual physical shape of the earth which is hard to describe mathematically because of the local surface irregularities and sea land variations In geodetic terms it is the particular equipotential surface which coincides with mean sea level and which may be imagined to extend through the continents This surface is everywhere perpendicular to the force of gravity GPS with differential corrections applied Acutime 2000 Synchronization Kit User Guide GPS GPS antenna GPS processor GPS receiver GPS time HDOP host system HOW Glossary Global Positioning System A satellite based navigation system operated and maintained by the U S Department of Defense and consisting of a constellation of 24 satellites providing worldwide 24 hour three dimensional 3 D GPS coverage These satellites transmit signals used by GPS receivers to determine precise location position velocity and time solutions GPS signals are available in all weather conditions This system also includes 5 monitor ground stations 1 master control ground station and 3 upload ground stations GPS is emerging as the technology of choice in many timing applications including site and network synchronization An antenna designed to receive GPS radio navigation signals An electronic device that interpr
147. formation A new ephemeris is available usually on the hour Especially important for Differential GPS operation that the IODE change is tracked at both the reference station and mobile stations Interference in either transmitting or receiving signals caused by other radio signals at exactly or approximately the same frequency See satellite masks A measure of the maximum Position Dilution of Precision PDOP that is acceptable in order for the GPS processor to determine a location solution see PDOP The name given to the GPS satellites built by Rockwell International which is an acronym formed from NAVigation System with Time And Ranging National Marine Electronics Association An association that defines marine electronic interface standards for the purpose of serving the public interest NMEA 0183 is a standard for interfacing marine electronics navigational devices The standard specifies the message format used to communicate with marine devices components Acutime 2000 Synchronization Kit User Guide Glossary packet An envelope for data which contains addresses and error checking information as well as the data itself parity A scheme for detecting certain errors in data transmission Parity defines the condition i e even or odd of the number of items in a set e g bits in a byte PDOP Position Dilution of Precision PDOP is a unitless figure of merit that describes how an uncertainty in pseudo range
148. ful 1 2 3 4 5 The illustrations are clear and helpful 1 2 3 4 5 The manual is too long justright too short Please answer the following questions Which sections do you use the most What do you like best about the manual What do you like least about the manual Optional Name Company Address Telephone Fax Please mail to Trimble Navigation Limited 645 North Mary Avenue P O Box 3642 Sunnyvale CA 94088 3642 Alternatively email your comments and suggestions to ReaderFeedback trimble com All comments and suggestions become the property of Trimble Navigation Limited
149. gle precision and the packet is masked for output by packet 8E 4D then the GPS receiver sends this packet each time a fix is computed The data format is shown below Table A 32 Report Packet 42 SINGLE meters SINGLE meters SINGLE meters time of fix SINGLE seconds The time of fix is in GPS time or UTC as selected by the I O timing option At start up this packet or packet 83 is also sent with a negative time of fix to report the current known position Packet 83 provides a double precision version of this information Acutime 2000 Synchronization Kit User Guide A 43 Trimble Standard Interface Protocol A 0x43 Report Packet 43 Velocity Fix XYZ ECEF Report This packet provides current GPS velocity fix in XYZ ECEF coordinates If the I O velocity option Packet 35 is set to XYZ ECEF and the packet is masked for output by packet 8E 4D then the GPS receiver sends this packet each time a fix is computed if selected by the I O timing option The data format is shown below Table A 33 Report Packet 43 X velocity SINGLE meters second Y velocity SINGLE meters second Z velocity SINGLE meters second bias rate SINGLE meters second time of fix SINGLE seconds The time of fix is in GPS time or UTC as selected by the I O timing option A 44 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x45 Report Packet 45 Software Version Informati
150. gnal is re acquired a new center frequency and search range is computed Each frequency range is searched in 500 Hz increments The duration of the code search at a given frequency is approximately one second and switches automatically F 8 Acutime 2000 Synchronization Kit User Guide Theory of Operation If ephemeris or almanac data is available for the lost satellite then the satellite s velocity is factored into the center frequency calculation The diminished accuracy of an older almanac is accounted for in the width of the search range If neither the ephemeris nor almanac is available then the Doppler frequency at last lock is searched for two minutes If the satellite has not been re acquired after two minutes then the maximum expected Doppler frequency based on satellite dynamics is searched If the current position is not accurately known the search width is increased If the smart antenna is computing velocity or velocity aiding is provided then the receiver s motion is also factored into the Doppler frequency If velocity information is not available then the dynamics code is used to determine the maximum expected Doppler frequency The re acquisition time for momentary signal blockages is typically under two seconds Acutime 2000 Synchronization Kit User Guide F 9 Theory of Operation F F 6 F 10 System Architecture The standard Acutime 2000 incorporates a proprietary DSP Digital Signal Processor which oper
151. gram is also available on the Trimble website www trimble com products acutime2000 B 1 Start Up The Serial Port Selection screen shown below appears at the start of the program x PC Serial Port com 1 This screen lets you choose which PC serial port the Acutime 2000 is connected to If the desired port is not available in the selection box you can start the program using the parameter c with being the number of the serial port you want to select Acutime 2000 Synchronization Kit User Guide B 1 Timing Receiver Monitor B B 2 Main screen The main screen for the Timing Receiver Monitor is shown below Timing Receiver Monitor 22 08 14 62130 86 Apr 7 2000 680 02 511707 1056 Overdetermined Clock Doing fixes 14 7 The main screen displays time position SV selection and data receiver status and timing outputs The status bar displays Tx and Rx activity program hints firmware version number and serial port settings The menu provides other options for sending data to and requesting data from the receiver For additional program information and help see the Help menu B 2 Acutime 2000 Synchronization Kit User Guide C NMEA 0183 NMEA 0183 is an interface protocol created by the National Marine Electronics Association The latest release of NMEA 0183 is Version 2 1 October 15 1995 This protocol was originally established to allow marine navigation equipment to share information NMEA
152. hat the NTP Service will use when it starts To do this use the Startup button in the Services applet and for example specify the desired account and correct password Also use the Services applet to ensure this newly installed service starts automatically on bootup C intp gt Acutime 2000 Synchronization Kit User Guide 6 21 NTP Software Installation and Configuration 6 bx Note Make sure to also type the exe extension of the file name The program has registered the NTP service with the operating system A message is printed informing the user to change the account name and password for NTP This is not necessary in later versions of the Windows NT port 6 22 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 6 3 Starting the Service The last steps are performed using the Services Applet in the Windows NT Control panel 1 Open the Control Panel Services Applet 2 Scroll to Network Time Protocol 3 Make sure Startup is set to Automatic 4 Click Start Service Status Startup Net Logon Started Automatic Network Associates McShield Started Automatic Network Associates Task Manager Started Automatic Network DDE Manual Network DDE DSDM Manual NetworkTimeProtocol Automatic Novell Target Service Agent Started Automatic Novell Workstation Manager Automatic Start Sap Paice Continue NT LM Security Support Provider Manual Startup pcANY
153. he navigation processor also collects the ephemeris and almanac data for all of the satellites and manages the Universal Asynchronous Receiver Transmitter UART or DUART interface The UART supports full duplex serial communication with the smart antenna The RS 232 and RS 422 versions of the Acutime 2000 block diagram for the GPS smart antenna are illustrated in Figure F 1 and Figure F 2 Acutime 2000 Synchronization Kit User Guide Theory of Operation Figure F 1 nternal Patc Acutime 2000 It 12 Pin nternal Patch Antenna Connector gt Pream gt i3 gt RF In Tx gt 4 Port B Tx eamp ASIC 7 Port B Rx lt 2 Port B Rx aema Clk In Microcontroller Tx gt 7 Port A Tx 2 GPS Receiver Port A ASIC Rx t i MCU Bus Event In lt 6 Event In Port A Rx A 11 PPS Out Flash PPS Out gt gt EPROM RAM 12 PPS Out Backup g vBack Voltage Vcc q Switching Power Supply lt oe la V Acutime 2000 Block Diagram RS 232 Version h Antenna Preamp RF gt ASIC TCXO 12 504MHz a 1 MCU Bus Flash EPROM RAM Microcontroller GPS Receiver asic Po P Event In rtA Rx PS Out Figure F 2 Switching Power Supply A lt lt Acu 12 Pin Connector 5 4 3 2 10 8
154. hronization Kit User Guide 0 00676865799761 NAD 27 Western US A 129 Trimble Standard Interface Protocol Table A 101 Datums Continued A axis 6378206 400 Eccentricity 0 00676865799761 Description NAD 27 Eastern US 6378206 400 0 00676865799761 I NAD 27 Alaska 6378206 400 0 00676865799761 NAD 27 Bahamas 6378206 400 0 00676865799761 NAD 27 San Salvador 6378206 400 0 00676865799761 NAD 27 Canada 6378206 400 0 00676865799761 NAD 27 Alberta BC 6378206 400 0 00676865799761 NAD 27 East Canada 6378206 400 0 00676865799761 NAD 27 Manitoba Ont 6378206 400 0 00676865799761 NAD 27 NW Ter Sask 6378206 400 0 00676865799761 FNAD 27 Yukon 6378206 400 0 00676865799761 NAD 27 Canal Zone 6378206 400 0 00676865799761 NAD 27 Caribbean 6378206 400 0 00676865799761 NAD 27 Central Amer 6378206 400 0 00676865799761 NAD 27 Cuba 6378206 400 0 00676865799761 NAD 27 Greenland 6378206 400 0 00676865799761 NAD 27 Mexico 6378137 0 0 00669438002290 NAD 83 Alaska 6378137 0 0 00669438002290 NAD 83 Canada 6378137 0 0 00669438002290 NAD 83 CONUS 6378137 0 0 00669438002290 NAD 83 Mex Cent Am A 130 6378388 0 0 00672267002233
155. ime 2000 Synchronization Kit User Guide E 17 NTP Diagnostics and Debugging E 5 Start configuration by typing configure E xterm Al E bash cat etc motd Linux 2 0 30 bash whoami root bash ls 1 total 2611 rw r r 1 sven users 2660615 May 10 23 44 ntp 4 0 92h tar gz bash gzip d ntp 4 0 92h tar gz bash ls 1 total 7601 ru r r 1 sven users 7751680 May 10 23 44 ntp 4 0 92h tar bash tar xf ntp 4 0 92h tar bash ls 1 total 7602 drwxr xr x 19 427 6011 1024 Apr 24 00 18 ntp 4 0 92h ru r r 1 sven users 7751680 May 10 23 44 ntp 4 0 92h tar bash cd ntp 4 0 92h bash configure creating cache config cache checking host system type 6 Ifthe configuration program fails or does not complete by creating make files you will need to consult with your software or system administrator to obtain the correct compiler and libraries for your system 7 After configuration is complete type make to begin the software build If the build does not complete sucessfully please consult with your software or system administrator to diagnose the problem E 18 Acutime 2000 Synchronization Kit User Guide 4 xterm updating creating creating creating creating creating creating creating creating creating creating creating creating creating creating creating creating creating creating bash bash bash cache config cache fconfig status Makefile ad jtimed Makefile clockstuf
156. ing low elevation satellites These satellites are however subject to significant signal degradation by the greater ionospheric and tropospheric attenuation that occurs They are also subject to more obscuration by the passing scenery when the receiver is in a moving vehicle The code phase data from those satellites is more difficult to decode and therefore has more noise Note A level of hysteresis in the signal level mask is allowed in the core operating software The hysteresis allows the receiver to continue using satellite signals which fall slightly below the mask and prevents the receiver from incorporating a new signal until the signal level slightly exceeds the mask This feature minimizes constellation changes caused by temporary fluctuations in signal levels Acutime 2000 Synchronization Kit User Guide gt lt Table A 69 Subcode Primary receiver Trimble Standard Interface Protocol PDOP Mask and Switch The PDOP mask is the maximum PDOP limit for which any 2 D or 3 D position solution will be made The PDOP switch is the level at which the receiver stops attempting a 3 D solution and tries for a 2 D solution when in automatic 2 D 3 D mode The switch level has no effect on either manual mode Raising the PDOP mask generally increases the fix density during obscuration but the fixes with the higher PDOP are less accurate especially with Selective Availability present Lowering the mask improves the average accurac
157. ing command packet 8E A9 If not disabled the self survey mechanism will automatically survey the antenna s position and then set the receiver to operate in a static time only mode Set the desired position fix mode using command packet BB After these steps are completed the Acutime 2000 is ready to operate properly in mobile applications While operating in a mobile application the Acutime 2000 can continue to output a PPS pulse as well as timing packets bX Note The accuracy of the PPS output pulse will be degraded by a factor of about 3 when the unit is operated in a mobile application Acutime 2000 Synchronization Kit User Guide 5 15 System Operation 5 5 6 5 16 Customizing Acutime 2000 Operations The Acutime 2000 provides a number of user configurable parameters that allow you to customize the operation of the unit These parameters are stored in a non volatile memory chip EEPROM to be retained during loss of power and through resets At reset or power up the Acutime 2000 configures itself based on the parameters stored in the EEPROM You can change the values of these parameters to achieve the desired operations using a variety of TSIP packets The Acutime 2000 configures itself based on the new parameter immediately but the new parameter value is not automatically saved to the EEPROM You must direct the Acutime 2000 to save the parameters to the EEPROM Parameters are grouped into sections of the EEPR
158. ion All other LLTP packets will be output immediately after the first LLTP packet completes Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol A 9 Event Packets Event packets 8F 0B and 8F 0A are output in response to the event input as configrured by packet 8E A5 A 10 Satellite Data Packets The following packets request data transmitted by the GPS satellites and satellite tracking information Table A 11 Satellite Data Packets Input ID Description Output ID Request almanac Request signal levels Request GPS system message Request almanac health page Request UTC parameters Request load satellite system data Set request satellite disable or ignore health Request last raw measurement Request satellite ephemeris status Request tracking status Acutime 2000 Synchronization Kit User Guide A 11 Trimble Standard Interface Protocol A A 11 Customizing Receiver Operations The following packets let you customize the receiver output for your application Table A 12 Customizing Receiver Operations Input ID 21 Description Request current time Output ID 41 23 Initial position XYZ Cartesian ECEF 24 Request receiver position fix mode 6D 26 Request receiver health 46 and 4B 27 Request satellite signal levels 47 2A Altitude for 2 D mode 4A 2B Initial position LLA 2E
159. ion see Compiling the NTP Distribution page E 17 Acutime 2000 Synchronization Kit User Guide 6 3 NTP Software Installation and Configuration 6 6 2 1 6 3 Installation Support Trimble is attempting to provide the best possible support for customers who use the Acutime NTP Synchronization Kit to transfer time to NTP hosts Due to the wide variety of systems peripherals and associated configurations Trimble is not able to provide assistance installing and testing NTP Technical support for installation and configuration of NTP servers is limited to NTP documentation and software available on the Trimble Navigation NTP Web site at www trimble com oem ntp Please consult with a qualified systems administrator to verify I O connections between the Acutime NTP reference clock and your host system For more information consult the Internet news group news comp protocols time ntp If you suspect a problem with the Acutime GPS receiver please see Chapter 2 Getting Started before calling Trimble technical support Pre Installation Check List Before beginning installation and configuration of NTP complete the following tasks Acutime 2000 Synchronization Kit User Guide 6 3 1 NTP Software Installation and Configuration GPS Preparation Perform the checkout installation and connection instructions in chapters 1 4 Note Temporary installations as described in Chapter 2 can be used to establish functional
160. ion or use of the Product or Software iv damage caused by accident lightning or other electrical discharge fresh or salt water immersion or spray or v normal wear and tear on consumable parts e g batteries THE WARRANTIES ABOVE STATE TRIMBLE S ENTIRE LIABILITY AND YOUR EXCLUSIVE REMEDIES RELATING TO PERFORMANCE OF THE PRODUCTS AND SOFTWARE EXCEPT AS OTHERWISE EXPRESSLY PROVIDED HEREIN THE PRODUCTS SOFTWARE AND ACCOMPANYING DOCUMENTATION AND MATERIALS ARE PROVIDED AS IS AND WITHOUT EXPRESS OR IMPLIED WARRANTY OF ANY KIND BY EITHER TRIMBLE NAVIGATION LIMITED OR ANYONE WHO HAS BEEN INVOLVED IN ITS CREATION PRODUCTION INSTALLATION OR DISTRIBUTION INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE TITLE AND NONINFRINGEMENT THE STATED EXPRESS WARRANTIES ARE IN LIEU OF ALL OBLIGATIONS OR LIABILITIES ON THE PART OF TRIMBLE ARISING OUT OF OR IN CONNECTION WITH ANY PRODUCTS OR SOFTWARE SOME STATES AND JURISDICTIONS DO NOT ALLOW LIMITATIONS ON DURATION OR THE EXCLUSION OF AN IMPLIED WARRANTY SO THE ABOVE LIMITATION MAY NOT APPLY TO YOU TRIMBLE NAVIGATION LIMITED IS NOT RESPONSIBLE FOR THE OPERATION OR FAILURE OF OPERATION OF GPS SATELLITES OR THE AVAILABILITY OF GPS SATELLITE SIGNALS Limitation of Liability TRIMBLE S ENTIRE LIABILITY UNDER ANY PROVISION HEREIN SHALL BE LIMITED TO THE GREATER OF THE AMOUNT PAID BY YOU FOR THE PRODUCT OR SO
161. itor If the bias uncertainty exceeds the threshold then ACE UTC GPS disables the PPS output The default bias uncertainty threshold is 300 meters but this parameter may be programmed by the application ACE UTC GPS limits the threshold to 3x10 meters Each time the application adjusts the packet 8E 4A settings the new settings are stored in nonvolatile memory 0x8E 4D Command Packet 8E 4D Automatic Packet Output Mask Automatic output of packets on Port 1 can be throttled using this command packet The current mask can be requested by sending this packet with no data bytes except the subcode byte The receiver returns packet 8F 4D The automatic packet output mask can be set by sending this packet with 4 data bytes This mask only disables automatic packet output Packets generated in response to TSIP set or query commands will always be output by the receiver Table A 76 Command Packet 8E 4D Meaning Subcode ID for this subpacket is always 0x4D Auto output 32 bit packet enable mask bitmap A 92 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol The bits are numbered in descending order of receipt starting with bit 31 as the MSB of Byte 1 down to bit 0 as the LSB of Byte 4 A 0 in the bit position disables automatic output of the associated packets a 1 in the bit position makes the associated packets available for automatic output Table A 77 describes the packets aff
162. ity of NTP but reliable performance cannot be achieved until the Acutime smart antenna is properly installed with clear view of the sky The Acutime and Synchronization Interface Module should be powered up PPS indicator LED should be flashing once per second indicating the output of data packets A valid UTC almanac has been acquired by the Acutime Smart Antenna This should be confirmed using the Acutime Monitor or TSIPCHAT applications Note NTP will not accept time stamps from the Acutime NTP reference clock until a valid UTC almanac has been obtained The UTC information is stored in non volatile memory and only erased during a factory reset operation Acutime 2000 Synchronization Kit User Guide 6 5 NTP Software Installation and Configuration 6 6 6 6 3 2 Host System Preparation Installation of NTP must be performed by a user with administrative or super user privileges Network Time Protocol can not coexist with other clock synchronization utilities such as the TimeServ utility available in the Microsoft Windows NT Resource Kit Any other time synchronization utility running on the host system must be stopped disabled or de installed The host system clock should be set manually to the correct time If your network already has a time server use the NTPDATE utility to reset the system clock is recommended For more information on using NTPDATE see Appendix E NTP Diagnostics and Debugging In absence of
163. kadj ct In function readvar tickadj ct787 warning declaration of fd shadows global declaration gcc g 02 Wall Wshadow hMwrite strings Wconversion Wpointer arith lcast q ual lstrict prototypes pipe o tickadj tickadj o libntp libntp a lsocke t lposixd lnsl lkvm lelf make 2 Leaving directory usr local ntp ntp 4 0 92h util make 2 Entering directory usr local ntp ntp 4 0 92h make 2 Leaving directory usr local ntp ntp 4 0 92h make 1 Leaving directory usr local ntp ntp 4 0 92h bash make install Making install in include make 1 Entering directory usr local ntp ntp 4 0 92h include To complete installation of NTP on your system see UNIX Installation page 6 24 Acutime 2000 Synchronization Kit User Guide E NTP Diagnostics and Debugging E 4 Windows NT Administration This section describes starting and stopping NTP on Windows NT and removing the NTP service from the system E 4 1 Controlling the NTP Service Use the Control Panel Services Applet to Stop or Disable the NTP service at any time This procedure is the same whether you installed the NTP service manually or using the installation program Services Ea zy Service Status Startup EventLog Started Automatic Messenger Manual Stan Net Logon Started Automatic Network DDE Manual Stop Network DDE DSDM Manual NetworkTimeProtocol Started Automatic Bey N
164. kets that are synchronized with the PPS output on Port B Acutime 2000 Synchronization Kit User Guide 4 Acutime 2000 Connections TSIP timing packets 8F 0B 8F AB and 8F AC which work together as a pair of packets or 8F AD can be enabled on Port B using command packet 8E A5 These packets are sent within 30 milliseconds after the PPS pulse when enabled By default the Acutime 2000 automatically sends a variety of satellite data packets on Port B that you may not need You can disable these automatic output packets with command packet 8E A5 so that only the timing packets are sent You can also choose to receive these timing packets on Port A which serves as a dedicated transmit port for timing packets and use Port B to send commands and receive satellite data Port B can also be configured to transmit NMEA packets but these packets are not guaranteed to be sent within 30 milliseconds after the PPS output PortA By default the Port A receive line is used to receive external event inputs as described below however Port A can also receive serial RTCM differential corrections When you enable RTCM messages on Port A by sending command packets on Port B the event input mechanism is automatically disabled When RTCM messages are off the default state the event input mechanism is automatically enabled 4 3 4 Event Input The Acutime 2000 accepts an external event input in the form of an RS 422 pulse The external event p
165. l and message mask TA Double precision XYZ position 37 Double precision LLA position 37 Receiver configuration BB Port configuration BC Comprehensive time Auto Event Current datum values 8E 14 Current datum values 8E 15 Last fix with extra information fixed point 8E 20 Response to save EEPROM segments 8E 26 Manufacturing parameters 8E 41 Production parameters 8E 42 Response to revert segments to default 8E 45 PPS characteristics 8E 4A Survey limit 8E 4B Automatic packet output mask 8E 4D PPS output option 8E 4E Set PPS width Acutime 2000 only 8E 4F Packet broadcast mask 8E A5 Acutime 2000 Synchronization Kit User Guide A 17 Trimble Standard Interface Protocol A Table A 15 Report Packets Sent by GPS Receiver to User Continued Output ID Packet Description Response to self survey command 8E A6 Primary timing packet 8E AB Supplemental timing packet 8E AC UTC event time Event Auto A 18 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol A 14 Packet Structure TSIP packet structure is the same for both commands and reports The packet format is lt DLE gt lt id gt lt data string bytes gt lt DLE gt lt ETX gt lt DLE gt is the byte 0x10 lt ETX gt is the byte 0x03 and lt id gt is a packet identifier byte which can have any value except for lt ETX gt a
166. len 12 Table E 2 shows troubleshooting options Table E 2 Troubleshooting Incorrect Port and Bad Data Possible Problem Solution The host is connected to the wrong Acutime port NTP requires connection with Acutime Port A Connect Acutime Port A to the host serial port The Acutime Port A serial port configuration does not match the NTP configuration Acutime 2000 Synchronization Kit User Guide Verify Acutime Baud Rate Parity Start and Stop Bits and Protocol settings NTP Diagnostics and Debugging E 2 6 Serial Port is Unavailable When NTP is unable to open a serial port the following debug message is generated along with an error report in the system log Palisade 2 start open dev Acutime2 failed A failed serial port open attempt is shown below 4 xterm Of x lucky_first ntpd d create_sockets 123 bind fd 5 family 2 port 123 addr 0 0 0 0 flags 1 bind fd 6 family 2 port 123 addr 127 0 0 1 flags 0 bind gt fd 7 family 2 port 123 addr 155 63 33 57 flags 1 init_iot maxactivefd 7 Palisade 2 start open dew palisade2 failed resolving igq trimble com loop_configt state 2 freq 40 642 report_event system event event_restart 0x01 status sync_alarm sync_unspe c 1 event event_unspec 0xc010 auth_agekeys at 1 keys 1 expired 0 key_expire_all at 1 private d2389037 oo 155 63 32 173 mode 3 vers 4 min 6 max 10 flags 0x0001 ttl 0 key 0 On a Windows NT s
167. lization data from an operating GPS receiver via a data logger or computer and then using that data to initialize a second GPS receiver unit The GPS receiver returns packet 58 Note The GPS receiver can initialize itself without any data from the user it just requires more time To request data without loading data use only bytes 0 through 2 To load data use all bytes Caution Proper structure of satellite data is critical to receiver operation Requesting data is not hazardous loading data improperly is hazardous Use this packet only with extreme caution The data should not be modified in any way It should only be retrieved and stored for later reload Acutime 2000 Synchronization Kit User Guide A 35 Trimble Standard Interface Protocol Table A 23 Command Packet 38 Meaning 0 Operation Byte 1 Request data from receiver 2 Load data into receiver 1 Type of data Byte 1 Not used 2 Almanac 3 Health page T_oa WN_oa 4 lonosphere 5 UTC 6 Ephemeris 2 Sat PRN Byte 0 Data that is not satellite ID specific 1 32 satellite PRN number 3 length n Byte Number of bytes of data to be loaded 4ton 3 data n Bytes A 36 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x39 Command Packet 39 Satellite Attribute Database Command Normally the GPS receiver selects only healthy satellites based on transmitted values in the ephemeris and almanac that satisfy all mask
168. m a satellite and uses that time The receiver disregards the time in packet 2E Acutime 2000 Synchronization Kit User Guide A 53 Trimble Standard Interface Protocol A 0x4F A 54 Report Packet 4F UTC Parameters Report This packet is sent in response to command packet 2F and contains 26 bytes It reports the UTC information broadcast by the GPS system For details on the meanings of the following parameters consult ICD 200 Sections 20 3 3 5 2 4 20 3 3 5 1 8 and Table 20 IX On the simplest level to get UTC time from GPS time subtract AT s seconds The other information contained in this packet indicates when the next leap second is scheduled to occur Table A 45 Report UTC Parameters DOUBLE SINGLE INTEGER SINGLE INTEGER INTEGER INTEGER INTEGER Acutime 2000 Synchronization Kit User Guide 0x54 0x55 Trimble Standard Interface Protocol Report Packet 54 Bias and Bias Rate Report The receiver sends this packet to provide the computed clock only solution when the receiver is in the manual or automatic Overdetermined Clock mode or Time Only 1 SV mode Table A 46 Report Packet 54 Bias SINGLE meters Bias rate SINGLE meters second Time of fix SINGLE seconds The bias is the offset of the receiver internal time clock from GPS time Bias is expressed as meters of apparent range from the satellites It is used to correct the one PPS output Bias rate is th
169. mance of a GPS receiver at power on is determined largely by the availability and accuracy of the satellite ephemeris data and the availability of a GPS system almanac F 2 Acutime 2000 Synchronization Kit User Guide F F 2 F 2 1 Theory of Operation Satellite Acquisition and Time to First Fix This section describes satellite acquisition times for different start conditions Cold Start The term cold start describes the performance of a GPS receiver at power on when no navigation data is available Cold signifies that the receiver does not have a current almanac satellite ephemeris initial position or time The cold start search algorithm applies to a smart antenna that is powered on without the memory backup circuit connected to a source of DC power Since the Acutime 2000 has no provision for external backup power it always operates from a cold start This is the condition of the GPS module as received from the factory In a cold start condition the receiver automatically selects a set of satellites and dedicates an individual tracking channel to search the Doppler frequency for each satellite in the set If none of the selected satellites are acquired after a pre determined period of time time out the receiver selects a new search set of satellites and repeats the process until the first satellite is acquired As satellites are acquired the receiver automatically collects ephemeris and almanac data The smart antenna us
170. manual contains the following Chapter 1 Introduction describes the Acutime 2000 GPS smart antenna Chapter 2 Getting Started describes how to quickly install connect and operate the Acutime 2000 Chapter 3 Acutime 2000 Installation provides general installation guidelines Chapter 4 Acutime 2000 Connections provides detailed interfacing guidelines for connecting the Acutime 2000 GPS smart antenna to the host system Chapter 5 System Operation describes the operating characteristics of the Acutime 2000 from power up through the output of GPS information GPS timing applications are also described Chapter 6 NTP Software Installation and Configuration desrcibes the use of the Acutime 2000 in a NTP time server implemintation Appendix A Trimble Standard Interface Protocol defines the TSIP protocol and the structure of all message packets Appendix B Timing Receiver Monitor describes the monitor program included on the Acutime 2000 CD ROM Appendix C NMEA 0183 provides a brief description of the NMEA 0183 protocol and defines the structure ofthe NMEA message output by the Acutime 2000 Appendix D Specifications and Drawings includes the specifications and mechanical drawings for the Acutime 2000 GPS smart antenna interface cables Appendix E NTP Diagnostics and Debugging provides information to help troubleshoot NTP problems Acutime 2000 Synchronization Kit User Guide About This Manual Appen
171. ming Packets 8F AB and 8F AC are automatically output at 1 Hz These packets are part of the low latency packet series AB AC AD OB See section A 8 Acutime 2000 Synchronization Kit User Guide A 9 Trimble Standard Interface Protocol A A 8 Low Latency Timing Packets The Ace UTC and Acutime 2000 feature a sequence of high priority timing super packets which are output within a bounded period of time after the PPS The LLT packets offer an advanced data interface for applications requiring accurate data reports in a time constrained environment On Acutime 2000 and Ace UTC the first super packet will start transmission no later than 15 25 ms after the PPS transition The super packets which meet the LLTP criteria are in the table below The packets are listed in order of output priority Output of each packet can be turned on off by using the mask in packet 8E AS but the output order cannot be changed The packets may also be requested please refer to the specific packet documentation for details Table A 10 Low Latency Timing Packets LLTP Packet ID Description Request Packet ID 8F AB Primary Timing 8E AB 8F AC Supplemental Timing 8E AC 8F AD Primary UTC Time 8E AD 8F 0B Comprehensive Time and Position 8E 0B gt lt A 10 The receiver will output all other TSIP packets after the transmission of LLTP packet sequence is complete Note Only the first packet will meet the LLTP specificat
172. mode is used only when the user application requires all satellite measurements to be identical to the position time tag If a satellite that is in the selected set for the solution is lost then no fix will be made until a new selection is made The synchronized measurement mode combined with the minimized projection timing mode see next paragraph allows absolutely no measurement projection However obscurations may reduce the fix density when there are limited satellites Use this mode cautiously Acutime 2000 Synchronization Kit User Guide A 33 Trimble Standard Interface Protocol A Minimized Projection This bit controls the time of the position fix relative to the time of the satellite range measurements The default mode is OFF In this mode the time of solution is the time at which the GPS position fix is computed Thus all measurements are projected by an interval which is roughly the amount of time it takes to compute the solution This approach minimizes the latency between the time tag of the computed solution and the solution output The drawback is that the measurement projection which is only about 100 ms may induce some error during high accelerations Alternatively when minimized projection is ON the time of the solution is the time of the most recent measurements Thus if all measurements are taken at exactly the same time there is no measurement projection If a selected satellite s measurement time lags the
173. month year count reported does not increment to the next day until the beginning of the second following the leap event Decoding of the 8F AD packet provides complete leap status information The UTC offset is incremented at the beginning of the first second following the leap second A 104 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x8F 14 Report Packet 8F 14 Current Datum Values This packet contains 43 data bytes with the values for the datum currently in use and is sent in response to packet 8E 14 If a built in datum is being used both the datum index and the five double precision values for that index are returned If the receiver is operating on a custom user entered datum the datum index is set to 4 and the five values are displayed These five values describe an ellipsoid to convert ECEF XYZ coordinate system into LLA Table A 86 Report Packet 8F 14 Super packet ID 14 Datum index Datum index 1 for custom DOUBLE DX meters DOUBLE DY meters DOUBLE DZ meters DOUBLE A axis meters DOUBLE Eccentricity squared none bX Note A complete list of datums is provided at the end of this appendix Acutime 2000 Synchronization Kit User Guide A 105 Trimble Standard Interface Protocol 00x8F 20 Report Packet 8F 20 Last Fix with Extra Information binary fixed point Table A 87 This packet provides information concerning the time and origin
174. n A 56 Acutime 2000 Synchronization Kit User Guide Trimble Standard Interface Protocol 0x57 Report Packet 57 Information About Last Computed Fix Report This packet provides information concerning the time and origin of the previous position fix The receiver sends this packet among others in response to packet 37 The data format is shown below Table A 48 Report Packet 57 Source of information Type Units BYTE 0 none 1 regular fix Tracking mode BYTE 0 Auto 1 Time Only 1 SV 2 2Dclock Hold 3 2D 4 3D 5 Overdetermined Clock 6 DGPS Reference Time of last fix SINGLE seconds GPS time Week of last fix INTEGER weeks GPS time Acutime 2000 Synchronization Kit User Guide A 57 Trimble Standard Interface Protocol A 0x58 Report Packet 58 Satellite System Data Acknowledge from Receiver This packet provides GPS data almanac ephemeris etc The receiver sends this packet under the following conditions 1 on request 2 in response to packet 38 acknowledges the loading of data The data format is shown below Table A 49 Report Packet 58 Meaning Operation Acknowledge Data Out not used Type of data Almanac Health page T_oa WN_oa lonosphere UTC Ephemeris 1 2 1 2 3 4 5 6 0 Sat PRN Data that is not satellite ID specific Satellite PRN number length n BYTE Number of bytes of data to follow 4 to n 3 data n BYT
175. n mask and healthy according to the almanac The receiver sends this packet only in response to packet 27 Table A 37 shows the data format Table A 37 Report Packet 47 Count BYTE Satellite number 1 BYTE Signal level 1 SINGLE Satellite number 2 BYTE Signal level 2 SINGLE etc etc Up to 12 satellite number signal level pairs may be sent indicated by the count field Signal level is normally positive If it is zero then that satellite has not yet been acquired If it is negative then that satellite is not currently in lock The absolute value of signal level field is the last known signal level of that satellite The signal level provided in this packet is a linear measure of the signal strength after correlation or de spreading Report Packet 48 GPS System Message Report This packet provides the 22 byte ASCII message carried in the GPS satellite navigation message The receiver sends this packet in response to packet 28 and when this data is received from a satellite The message is effectively a bulletin board from the Air Force to GPS users The format is free form ASCII The message may be blank Acutime 2000 Synchronization Kit User Guide 0x49 0x4A Trimble Standard Interface Protocol Report Packet 49 Almanac Health Page Report This packet provides health information on all 32 satellites Packet data consists of 32 bytes each containing the 6 bit health from almanac page 25 The first byte
176. nce If you have a problem and cannot find the information you need in the product documentation contact your sales representative Alternatively request technical support via email at trimble_support trimble com or by phone at 1 800 767 4822 Abbreviations In this manual the following abbreviations are used TSIP Trimble Standard Interface Protocol host system or host the device or instrument connected to the Acutime 2000 smart antenna The host system can be a PC network equipment or timing system depending on the application Document Conventions Italics identify software menus menu commands dialog boxes and the dialog box fields SMALL CAPITALS identify user commands directories filenames and filename extensions Helvetica represents messages printed on the screen Courier Bold represents information that you must type in a software screen or window Helvetica Bold identifies a software command button is an example of a hardware function key that you must press on a personal computer PC If you must press more than one of these at the same time this is represented by a plus sign for example Ctrl 0 Acutime 2000 Synchronization Kit User Guide xxiii About This Manual Cautions and Notes Cautions notes and tips draw attention to important information and indicate its nature and purpose w Caution Cautions describe operating procedures and practices required for correct ope
177. nd lt DLE gt The bytes in the data string can have any value To prevent confusion with the frame sequences lt DLE gt lt id gt and lt DLE gt lt ETX gt every lt DLE gt byte in the data string is preceded by an extra lt DLE gt byte stuffing These extra lt DLE gt bytes must be added stuffed before sending a packet and removed unstuffed after receiving the packet bX Note A simple lt DLE gt lt ETX gt sequence does not necessarily signify the end of the packet as these can be bytes in the middle of a data string The end of a packet is lt ETX gt preceded by an odd number of lt DLE gt bytes Multiple byte numbers integer float and double follow the ANSI IEEE Std 754 IEEE Standard for Binary Floating Point Arithmetic as illustrated below They are sent most significant byte first This may involve switching the order of the bytes as they are normally stored in Intel based machines Only the fractional part of the mantissa for real numbers SINGLE and DOUBLE is reported because the leading bit on the mantissa is always 1 Specifically INTEGER is a 16 bit unsigned number sent in two s complement format SINGLE float or 4 byte REAL is sent as a series of four bytes it has a precision of 24 significant bits approximately 6 5 digits DOUBLE 8 byte REAL is sent as a series of eight bytes a b c d e f g h it has a precision of 52 significant bits a little better than 15 digits Ac
178. nel receivers 8 channel receivers 8 channel receivers 8 channel receivers 8 channel receivers Byte 2 Acquisition flag O never acquired 1 acquired 2 re opened search Byte 3 Ephemeris flag O flag not set satellite 0 or 33 good ephemeris for this lt 4 hours old good health Byte 4 7 Signal level SINGLE same as in packet 47 hex Byte 8 11 GPS time of last measurement A 68 SINGLE seconds Acutime 2000 Synchronization Kit User Guide lt 0 no measurements have been taken 20 center of the last measurement taken from this satellite A Trimble Standard Interface Protocol Table A 58 Report Packet 5C Continued Byte ltem Byte 12 15 Elevation Type Units SINGLE radians Value Meaning Approximate elevation of this satellite above the horizon Updated about every 15 seconds Used for searching and computing measurement correction factors Byte 16 19 Azimuth SINGLE radians Approximate azimuth from true north to this satellite Updated about every 15 seconds Used for computing measurement correction factors Byte 20 old measurement flag N A Byte 21 Integer msec flag N A Byte 22 bad data flag N A Byte 23 Data collection flag N A Acutime 2000 Synchronization Kit User Guide A 69 Trimble Standard Interface Protocol A 0x5F 11 Report Packet 5F 11 EEPROM Segment Status Reports This
179. nfiguration file you need to define additional sources of time for the server Each time server on the network should have at least three independent clock references to function optimally In large organizations there may already be network time servers in operation Consult your system administrators for their names or IP numbers If you have Internet Access look at the list of public time servers and choose geographically close sites for your sources You should choose a minimum of one time server and it is a good idea to choose three or more for redundancy An example of a time server entry is provided in the sample configuration file Create one server line item with the name or IP number for each available time server Acutime 2000 Synchronization Kit User Guide 6 13 NTP Software Installation and Configuration 6 14 6 5 4 Additional Configuration Information This documentation provides only minimal required configuration information For complete information about available configuration options please refer to documentation provided with your NTP distribution Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 6 Windows NT Installation The following instructions are specific to installing the port of NTP for Windows NT distributed by Trimble Navigation at ftp ftp timble com pub ntp binaries winnt bX Note To install NTP you must log into the Windows NT system as a
180. nnection instructions 4 7 power 4 7 timing packet 4 8 timing pulse 4 7 connection diagram 2 3 coordinate systems F 7 NMEA 0183 F 7 TSIP F 7 D Department of Defense Glossary 6 document conventions XXxiii dynamic limits F 8 Index 1 E ECEF A 30 electrical specifications D 3 elevation mask 5 2 environmental specifications D 2 event input 4 9 external event input 5 9 G garage search strategy F 5 getting started 2 1 Glossary Glossary 1 GPS timing 5 12 H HAE A 30 health of receiver A 46 health of satellite A 49 height above ellipsoid A 30 hot start F 5 installation 3 1 software 6 1 UNIX 6 24 Windows NT 6 15 interface and power connections 4 2 interface cable routing and securing 3 5 introduction 1 1 items required for installation 2 1 Index 2 main screen B 2 manual installation Windows NT 6 17 monitoring NTP 6 31 mounting the smart antenna 3 4 N Network Time Protocol NTP 6 1 NMEA 0183 F 7 NMEA 0183 message formats C 5 notes XX1V NTP configuration file 6 11 monitoring 6 31 software installation 6 10 time servers 6 2 NTP software installation and configuration 6 1 O operation theory F 1 organization XX other information xxii overdetermined timing mode 5 5 P packet descriptions A 20 Palisade configuration 6 12 PDOP mask 5 3 performance F 8 dynamic limits F 8 re acquisition F 8 Acutime 2000 Synchronization Kit User Guide update rate F 8 performance specifications
181. numbered but are in numerical order The disabled satellites are signified by a 1 and enabled satellites are signified by a 0 Table A 55 Report Packet 59 Meaning Operation The remaining bytes tell whether receiver is allowed to select each satellite The remaining bytes tell whether the receiver heeds or ignores each satellite s health as a criterion for selection Satellite 32 BYTES Depends on byte 0 value 1 byte per satellite Enable satellite selection or heed satellite s health Default value Disable satellite selection or ignore satellite s health Acutime 2000 Synchronization Kit User Guide A 63 Trimble Standard Interface Protocol A 0x5A A 64 Report Packet 5A Raw Measurement Data Report This packet provides raw GPS measurement data If the I O auxiliary option for raw data has been selected packet 35 and it is masked for output by packet 8E 4D the receiver outputs a packet 5A for each satellite being tracked once per second The receiver also sends this packet in response to packet 3A The data format is shown below Table A 56 Report Packet 5A Satellite PRN number BYTE reserved SINGLE Signal level SINGLE Code phase SINGLE 1 16th chip Doppler SINGLE Hertz Time of DOUBLE seconds Measurement Note Report Packet 5A provides the raw satellite signal measurement information used in computing a fix The satellite PRN Byte 0 numb
182. oes cause harmful interference to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient or relocate the receiving antenna Increase the separation between the equipment and the receiver Connect the equipment into an outlet on a circuit different from that to which the receiver is connected Consult the dealer or an experienced radio TV technician for help Changes and modifications not expressly approved by the manufacturer or registrant of this equipment can void your authority to operate this equipment under Federal Communications Commission rules European Community CE Directive Conformance Statement The Acutime 2000 GPS Smart Antenna conforms with the essential requirements of the EMC Directive 89 336 EEC A Declaration of Conformity indicating the requirements met has been signed at Trimble Navigation Limited 645 North Mary Avenue Sunnyvale CA 94086 USA Contents About This Manual Scope and Audience o e XIX Organization ocio ee ae ee ees XX Reader Feedback 0 00000 0000004 XXI Related Information xxii Update Notes cne e oea i a oea ia e e xxii World Wide Web WWW Site xxii Technical Assistance xxiii ADDTevIatIONS io taz xxiii Document Conventions
183. of the previous position fix This is the last calculated fix it could be quite old The receiver sends this packet in response to Packet 8E 20 it also can replace automatic reporting of position and velocity packets Automatic output of 8F 20 must also be enabled by setting bit 5 of byte 0 in command packet 0x35 and bit 0 of bytes 1 2 in command packet 0x8E AS The data format is shown in the table below Item Type Report Packet 8F 20 Meaning 0 Subpacket ID BYTE ID for this subpacket always 0x20 1 KeyByte BYTE Reserved for Trimble DGPS postprocessing 2 3 east velocity units 0 005 m s or 0 020 m s see Byte 24 INTEGER Overflow 0 x 8000 4 5 north velocity units 0 005 m s or 0 020 m s see Byte 24 INTEGER Overflow 0 x 8000 6 7 up velocity INTEGER units 0 005 m s or 0 020 m s see Byte 24 Overflow 0 x 8000 8 11 Time of Week GPS Time in milliseconds UNSIGNED LONG 12 15 Latitude LONG Latitude units 231 semicircle according to INTEGER current datum Range 230 to 2 16 19 Longitude Longitude east of meridian units an UNSIGNED LONG semicircle according to current datum Range 0 to 232 20 23 Altitude LONG Altitude above ellipsoid mm according current INTEGER datum 24 Velocity Scaling When bit 0 is set to 1 velocities in Bytes 2 7 have been scaled by 4 A 106 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Table A 87 Repo
184. olic Link Names Operating system Port Name Serial Port Sample Link Enumeration Linux ttyS 0 1 2 devittySO dev AcutimeO HPUX cua 0 1 2 dev cua1 dev Acutime1 SUN OS Solaris tty a b c devittyc dev Acutime2 Acutime 2000 Synchronization Kit User Guide 6 27 NTP Software Installation and Configuration 6 7 3 Hardware Configuration You may want to use a system configuration tool to enable and configure system serial ports to function with Acutime Turn off any login service or modem server that may be attempting to use the port Admintool Serial Ports Figure 6 3 Disabling Serial Port Services Using an Administrative Tool Acutime NTP uses the following serial port configuration 9600 baud 8 bits 1 stop bit odd parity No DSR signal is generated No DTR signal is required Flow control protocols are not acknowledged If your UNIX system requires initialization of serial devices use a configuration corresponding to these parameters 6 28 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 7 4 Copying Executable Files If you obtained binary executable versions of the NTP daemon and its utilities you will have to unpack the archive and manually move the files to the desired storage directory NTP is commonly located in USR LOCAL BIN You must also edit your startup scripts to point to the location of the NTP exec
185. on Report This packet provides information about the version of software in the Navigation and Signal Processors The GPS receiver sends this packet after power on and in response to packet 1F Table A 34 Report Packet 45 Major version number Minor version number Month Day Year number minus 1900 Major revision number Minor revision number Month Day 0 1 2 3 4 5 6 7 8 9 Year number minus 1900 The first five bytes refer to the Navigation Processor and the second five bytes refer to the Signal Processor Acutime 2000 Synchronization Kit User Guide A 45 Trimble Standard Interface Protocol A 0x46 Report Packet 46 Health of Receiver Report This packet provides information about the satellite tracking status and the operational health of the receiver The receiver sends this packet after power on or software initiated resets in response to packet 26 during an update cycle when a new satellite selection is attempted and when the receiver detects a change in its health Packet 4B is always sent with this packet The data format is given in the following table Table A 35 Report Packet 46 Meaning Status code Doing position fixes Do not have GPS time yet Not used PDOP is too high No usable satellites Only 1 usable satellite Only 2 usable satellites Only 3 usable satellites The chosen satellite is unusable Error codes A 46 Acutime 2000
186. on SV elevation above horizon SNR Signal strength DOP Self survey only Elevation Mask Satellites below 10 elevation are not used in the solution Generally signals from low elevation satellites are of poorer quality than signals from higher elevation satellites These signals travel farther through the ionospheric and tropospheric layers and undergo distortion due to these atmospheric conditions Acutime 2000 Synchronization Kit User Guide 5 System Operation SNR Mask Although the Acutime 2000 is capable of tracking signals with SNRs as low as 2 the default SNR mask is set to 4 to eliminate poor quality signals from the fix computation Low SNR values can result from low elevation satellites partially obscured signals for example dense foliage multi reflected signals multipath Multi reflected signals also known as multipath can degrade the position solution Multipath is most commonly found in urban environments with many tall buildings and a preponderance of mirrored glass Multi reflected signals tend to be weak low SNR value since each reflection diminishes the signal Setting the SNR mask to 4 or higher minimizes the impact of multi reflected signals PDOP Mask Position Dilution of Position PDOP is a measure of the error caused by the geometric relationship of the satellites used in the position solution Satellite sets that are tightly clustered or aligned in the sky have a high PDOP
187. onds 8E 4F PPS driver switch Table 5 6 Parameter XYZ coordinates 3 At least 1 SV Factory default Such that LLA coordinates are all zeros Position Information segment 6 Set 8E 4E Request Report Have position flag 5 18 FALSE Acutime 2000 Synchronization Kit User Guide 5 System Operation Table 5 7 Self Survey Configuration segment 7 Parameter Factory default Set Request Survey enable flag Survey length Survey save flag Survey operating Full Position 3D dimension The survey operating dimension can be set to auto and 2D if segments are saved 8E 26 while a survey is in process The receiver uses the dimension setting saved for the next survey Ifa reference altitude has been entered and the receiver is set to 2D survey the reference altitude is used If a reference altitude has not been entered and the receiver is set to 2D survey an altitude of 0 is used for 2D survey not recommended Table 5 8 NMEA Configuration segment 8 Parameter Factory default Set Request Report NMEA message mask 0x00000020 ZDA 7A TA TA NMEA message rate 1 TA TA TA NMEA options 0 TA TA TA Table 5 9 UTC Information segment 11 Acutime 2000 Synchronization Kit User Guide 5 19 System Operation 5 5 20 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 1 Network Time Pr
188. ooting Acutime is Not Responding E 12 Troubleshooting Incorrect Port and Bad Data E 15 Dynamic Upper Bound F 8 Acutime 2000 Synchronization Kit User Guide xvii List of Tables xviii Acutime 2000 Synchronization Kit User Guide About This Manual Welcome to the Acutime 2000 Synchronization Kit User Guide This manual describes how to integrate the Acutime 2000 smart antenna with your host system bX Note The Acutime 2000 has replaced the Palisade and Palisade Network Time Protocol NTP It can be used with NTP See Chapter 6 or as a stand alone timing receiver In some instances the term Palisade is still used in the screen captures and text in this manual This will be updated in future revisions Scope and Audience Even if you have used other Global Positioning System GPS products before Trimble recommends that you spend some time reading this manual to learn about the special features of this product If you are not familiar with GPS Trimble recommends that you do one of the following Read the booklet GPS A Guide to the Next Utility available from Trimble Complete the GPS tutorial at www trimble com gps The following sections provide you with a guide to this manual as well as to other documentation that you may have received with this product Acutime 2000 Synchronization Kit User Guide xix About This Manual XX Organization This
189. or longer cable runs an RS 422 interface is recommended 4 6 Acutime 2000 Synchronization Kit User Guide 4 Acutime 2000 Connections 4 3 Connection Instructions This section provides detailed information for connecting the Acutime 2000 s power timing pulse and data packet lines 4 3 1 Power Connection Red and Black Wires The red wire Acutime 2000 pin 1 and black wire Acutime 2000 pin 9 in the interface cable support the power and ground connections respectively The Acutime 2000 features a switching DC power supply which accepts from 8 to 36 volts The Acutime 2000 is protected against reverse polarity and brief over voltage conditions however sustained over voltage conditions can cause permanent damage 6 Warning Voltages exceeding 36 volts can cause permanent damage to the Acutime 2000 s power supply The typical power consumption of the Acutime 2000 at an input voltage of 12 volts is 110 milliAmps or 1 3 watts bX Note The Acutime 2000 requires a minimum of 8 volts at the interface connector When specifying the supply voltage line losses in the interface cable must be considered To account for line loss the supply voltage may need to exceed 8 volts to satisfy the minimum voltage at the Acutime 2000 4 3 2 Timing Pulse Connections The Acutime 2000 outputs a timing pulse for use in timing and synchronization applications The timing pulse is generated using an RS 422 line driver circuit pins 11 an
190. ormation about part numbers refer to www trimble com products acutime2000 Acutime 2000 Synchronization Kit User Guide 2 Getting Started This chapter describes how to quickly install connect and communicate with the Acutime 2000 GPS Smart Antenna bX Note For permanent installations see the instructions in Chapter 3 You will need the following items a PC running Windows the Timing Receiver Monitor software for Windows also available on the web site an interface cable for the smart antenna an RS 422 to RS 232 converter included in the Acutime 2000 Starter Kit You may require this if you are using an Acutime 2000 with an RS 422 interface In many cases however a PC s communication port is flexible enough to accept an RS 422 signal without a converter connectors adapters for connecting the interface cable to the PC s communication port The interface cable included in the Acutime 2000 Starter Kit is terminated with a DB25 connector The standard interface cables are not terminated with connectors a DC power source The Acutime 2000 accepts 8 36 V DC power and draws approximately 110 milliamps at 12 volts Acutime 2000 Synchronization Kit User Guide 2 1 Getting Started 2 A mounting pole The Acutime 2000 accepts a standard 1 14 straight thread 2 1 Connecting the Smart Antenna The Acutime 2000 can be placed anywhere with a clear view of the sky Connect the interface cable to th
191. osition used for clock only fixes Limits 1 to 2 1 fixes bX Note After disabling the self survey the survey in progress can be stopped by issuing a restart self survey command 0x8E A6 Table A 82 Command Packet 8E A9 Data Format lt lt segment 7 gt gt Description Subcode Self Survey Disabled Enable Enabled factory default Position Save Don t save position factory Flag default Save self surveyed position Self Survey UINT32 Number of fixes Length factory default 2000 Reserved UINT32 0 Acutime 2000 Synchronization Kit User Guide A 99 Trimble Standard Interface Protocol A 0x8E AB Command Packet 8E AB Request Primary Timing Packet This command packet may be used to request the primary timing packet 8F AB To receive report packet 8F AB once per second use command 8E A5 to enable the automatic output The Request Type item determines how the ACE UTC GPS will reply to this command Request Type 0 The most current primary timing values will be sent in report packet 8F AB immediately e Request Type 1 The response is not sent immediately Instead report packet 8F AB is sent within 20ms after the next PPS output This is the same time that the packet would be automatically sent if enabled Request Type 2 Same as type 1 except that both report packets 8F AB and Ox8F AC are sent after the next PPS output Table A 83 Command Packet 8E AB Meaning Subcode
192. otocol The Network Time Protocol NTP is a family of programs that are used to adjust the system clock on your computer and keep it synchronized with external sources of time NTP was developed by Dr David Mills at the University of Delaware Information is available at the official NTP web site www eecis udel edu ntp The Network Time Protocol is designed to function as a background task on the host operating system so that its operation is transparent to the user and system tasks Time data is transferred from external time sources to clients within your domain NTP achieves accuracy in the sub microsecond to low millisecond range with hardware currently available This section describes installation of the NTP software on a designated network computer for use with the Acutime Smart Antenna as primary reference clock Acutime 2000 Synchronization Kit User Guide 6 1 NTP Software Installation and Configuration 6 gt lt 6 2 Note The Acutime 2000 has replaced the Palisade and Palisade NTP lt can be used with NTP or as a stand alone timing receiver In some instances the term Palisade is still used in the screen captures and text in this manual This will be updated in future revisions NTP Time Servers A primary network time server is a networked computer connected to an accurate external source of reference time The time server synchronizes its clock to the reference clock s time and provides accurate time of d
193. ovell Target Service Agent Started Automatic Continue Novell Workstation Manager Automatic NT LM Security Support Provider Started Manual Startup pcANYWHERE Host Service Manual ha _ HWY Profiles Startup Parameters FO Help E 4 2 Removing the NTP Service If you used the automatic installation procedure for installing NTP de install the NTP software using the Control Panel Add Remove programs applet The NTP service can only be removed using the INSTSRV EXE utility The NTP service must be stopped prior to removing 1 To stop the NTP Service click Stop in the Control Panel Services Applet Acutime 2000 Synchronization Kit User Guide E 21 NTP Diagnostics and Debugging jz Command Prompt C ntp gt dir E 2 Start a command prompt window and change to the directory containing the INSTSRV EXE utility 3 Type instsrv remove Volume in drive C has no label Volume Serial Number is D845 2F2F Directory of C ntp 02 02 52p 02 02 02 01 02 46p 46p 22p 21p 22p 22p 02 03 21p 18p 9 lt DIR gt File s C ntp gt instsru remove Delete of Service C intp gt E 22 36 864 98 304 65 536 102 400 51 344 167 936 Instsru exe ntpq exe ntpdate exe ntpdc exe ntptrace exe ntpd exe debug 528 384 bytes 9 437 184 bytes free NetworkTimeProtocol was SUCCESSFUL The program reports successful removal of the service The executable
194. packet provides time information once per second if enabled with command packet 8E A5 GPS week number GPS time of week TOW UTC integer offset time flags date and time of day TOD information is provided This packet can be requested with packet 8E AB This packet will begin transmission within 30 ms after the PPS pulse to which it refers Data Fields Time of Week This field represents the number of seconds since Sunday at 00 00 00 GPS time for the current GPS week Time of week is often abbreviated as TOW Week Number This field represents the current GPS week number GPS week number 0 started on January 6 1980 Unfortunately the GPS system has allotted only 10 bits of information to carry the GPS week number and therefore it rolls over to 0 in just 1024 weeks 19 6 years and there is no mechanism built into GPS to tell the user to which 1024 week epoch the week number refers The first week Acutime 2000 Synchronization Kit User Guide A 115 Trimble Standard Interface Protocol A A 116 number roll over occurred as August 21 1999 GPS transitioned to August 22 1999 GPS The ACE UTC GPS adjusts for this week rollover by adding 1024 to any week number reported by GPS that is less than week number 1023 which began on December 14 1997 With this technique the ACE UTC GPS will provide an accurate translation of GPS week number and TOW to time and date until July 30 2017 UTC Offset This field represents the current in
195. pdate Rate 1Hz Accuracy Dynamic SPS with S A Dynamic DGPS Position 40m CEP 1 5m CEP Velocity 0 25 m s CEP 0 05 m s CEP Time to First Fix no stored position 8 channel typical cold start lt 120 seconds Time to First PPS stationary with stored position e g recovery after power outage lt 60 seconds Re acquisition after 60 second signal loss lt 2 seconds 90 Dynamics Velocity D 2 500 m sec maximum D Specifications and Drawings Table D 3 Acceleration Performance Specifications Continued 4g 39 2 m sec Jerk 20 m sec PPS output Physical Interface RS 422 Width 10 microseconds default User programmable from 10 microseconds to 500 milliseconds On Time Edge Rising edge on time default User programmable rising or falling Resolution 80 nanoseconds quantization error reported through TSIP Accuracy one sigma UTC 50 nanoseconds static UTC 150 nanoseconds dynamic TDOP3S External Event Capture Interface RS 422 485 or RS 232 Resolution 320 nanoseconds Minimum Pulse Width 1 microsecond rising edge on time Reporting Mechanism Table D 4 Prime Power TSIP Packet Electrical Specifications 8 Vdc to 36 Vdc reverse polarity protection Power Consumption 110mA 12 volts 1 3 watts typical lt 1 5 watts
196. pplication In this mode messages reporting system events are printed to the screen which reveal more information about errors and problems encountered by the program In order to be able to quickly diagnose communication problems with the Acutime it is helpful to have a debug version of NTP available The debug version allows starting NTP from the command line and observing text debug messages reporting events and failures If the normal operating exectable is not debug enabled you may need to consult your system documentation or obtain a debug enabled executable for your system using the software sources listed on page 6 3 This file should be stored in a dignostic tools folder on the system NTP is run in debug mode by a command such as ntpd d Acutime 2000 Synchronization Kit User Guide E NTP Diagnostics and Debugging E 2 1 Debug Mode Not Available If NTP is not compiled in debug mode it will report ntpd not compiled with DDEBUG option no DEBUG supportusage E 2 2 NTP Startup and Acutime Poll The startup of NTP debug output from start to the Acutime NTP reference clock s first poll response is shown below 4a xterm olx lucky_first ntpd d create_sockets 123 gt bind gt fd 5 family 2 port 123 addr 0 0 0 0 flags 1 bind gt fd 6 family 2 port 123 addr 127 0 0 1 flags 0 bind fd 7 family 2 port 123 addr 155 63 33 57 flags 1 init_iot maxactivefd 7 refclock_open fd 9 modem status 6
197. pread the signal energy over a bandwidth which is much greater than the signal information bandwidth This is done to provide the ability to receive all satellites unambiguously and to provide some resistance to noise and multi path Acutime 2000 Synchronization Kit User Guide Glossary 11 Glossary SPS start bit stop bit SV synchronous communication TSIP URA UTC UTC offset Glossary 12 Standard Positioning Service Refers to the GPS as available to the authorized user In asynchronous transmission the start bit is appended to the beginning of a character so that the bit sync and character sync can occur at the receiver equipment In asynchronous transmission the stop bit is appended to the end of each character It sets the receiving hardware to a condition where it looks for the start bit of a new character Space Vehicle GPS satellite A method of sending digital data in which the bits come at fixed rather than random times and are synchronized to a clock Trimble Standard Interface Protocol A binary hex packet bi directional protocol also known as the TANS protocol Used by a large number of Trimble sensors TSIP is the subset of TANS which is recognized by all Trimble sensors except the 4000 series The TSIP protocol is defined in full in Appendix A Satellite user range accuracy The URA is sent by the satellite and is computed by the GPS operators It is a statistical indicator of the cont
198. proximately every 16 seconds Output approximately every 2 5 minutes if the receiver is doing position fixes Receiver health Output approximately every 16 seconds if the receiver is not doing fixes Output approximately every 30 seconds if the receiver is doing position fixes Whenever any bit in the health message changes receiver health is automatically output Mode packet Output approximately every 30 seconds or when a constellation change occurs bX Note The background packets listed in this table are automatically output Background packets can be turned off For more information on this option see Command Packet 8E 4D A 8 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol A 6 Default Automatic Position and Velocity Reports for Acutime 2000 The Acutime 2000 automatically outputs position and velocity reports at set intervals Report intervals are controlled by packet 35 Table A 9 Automatic position and Velocity Reports Output ID Description Single precision XYZ position Double precision XYZ position Single precision LLA position Double precision LLA position Velocity fix XYZ ECEF See Note Velocity fix ENU DX Note When the receiver is in the Manual or Overdetermined Clock mode it outputs packet 54 to provide the computed clock only solution A 7 Automatic Primary and Supplemental Timing Reports for ACE UTC Ti
199. psoid MSL geoid Earth Mean Sea Level mode UTC Universal Coordinated Time Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Table A 22 Command Packet 35 Parameter Bit Default Associated Name Position Bit Packets Value Position XYZ ECEF Output 42 or 83 0 Off 1 On LLA Output 4A or 84 0 Off 1 On LLA ALT Output 4A or 84 0 HAE current datum 1 MSL geoid WGS 84 ALT input 0 HAE current datum 1 MSL geoid WGS 84 Precision of position output 0 Single precision packet 42 and or 4A 1 Double precision packet 83 and or 84 8F 20 Output 0 Off 1 On Unused Velocity 0 0 XYZ ECEF Output 0 Off 1 On ENU output 0 Off 1 On Unused Time type 0 GPS time 1 UTC Fix computation time 0 ASAP 1 Next integer sec Fix output time 0 When computed 1 Only on request Acutime 2000 Synchronization Kit User Guide A 31 Trimble Standard Interface Protocol A Table A 22 Command Packet 35 Continued Parameter Bit Default Associated Name Position Bit Packets Value Timing Synchronized measurements O Off 1 On Minimize Projection 0 Off 1 On Unused Auxiliary 0 Raw measurements 0 Off 1 oN Doppler smoothed codephase 0 Raw 1 Smoothed Unused Packet 35 is used to control the format and timing of the position and velocity output Bytes 0 1
200. ration and alert you to situations that could cause hardware damage or malfunction or software error bX Note Notes give additional significant information about the subject to increase your knowledge or guide your actions 6 Warning Warnings alert you to situations that could cause personal injury or unrecoverable data loss A warning precedes the text it references xxiv Acutime 2000 Synchronization Kit User Guide 1 Introduction This chapter provides an overview of the Acutime 2000 GPS smart antenna 1 1 Overview The Acutime 2000 is the latest in the Trimble family of GPS smart antennas The smart antenna allows OEMs and systems integrators to add GPS capability to their product lines quickly and easily without becoming GPS experts The Trimble Acutime 2000 GPS smart antenna encompasses the experience of four product lines Acutis Acutime Acutime II and Palisade The Acutime 2000 using Trimble s latest GPS technology is designed for wireless voice and data network synchronization It offers precise PPS output event input and also supports long cable runs The Acutime 2000 is composed of a set of matched subsystems This ensures optimal GPS performance long term reliability ease of operation and easy integration The Acutime 2000 houses the GPS receiver antenna power supply interface and other support circuitry in a single enclosure that mounts like an antenna As a sealed shielded self
201. receiver returns packet 8F 4E The current driver switch value can be requested by sending this packet with no data bytes except the subcode byte Driver switch values 3 and 4 only make sense in Overdetermined Timing mode In any position fix mode the effective choices are A 94 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol always on or during fixes which you get if you set the driver switch to 3 or 4 8E 4 Table A 78 Command Packet 0x8E 4E Meaning Subcode PPS PPS is always output driver PPS is output when at least switch one satellite is tracking PPS is output when at least three satellites are tracking 0x8E 4F Command Packet 8E 4F for Acutime 2000 only Set PPS Width This command packet sets the PPS width to a value in the range of 10 microseconds to 500 milliseconds The receiver returns packet 8F 4F The current PPS width can be requested by sending this packet with no data bytes except the subcode byte Table A 79 Command Packet 0x8E 4F COC TN Subcode BYTE PPS DOUBLE Seconds width Ox8E A5 Command Packet 8E A5 Set or Request Packet Broadcast Mask Use command packet 8E AS to set the packet broadcast masks or to request the current mask settings The ACE UTC replies to requests with response packet 8F A5 The broadcast mask is bitwise encoded to allow the user to turn on and off the automatic output broadcast of certain packets For those broadca
202. report packet is sent in response to command packet 3F 11 It contains all the segments in the EEPROM The Segment Status is bitwise encoded with the status of each segment and is cleared to 0 after it is read A zero in the bit field indicates that the segment contents are valid A one in the bit field indicates that the segment contents were corrupt and had to be reverted to their factory default values The Manufacturing and Production parameters Bits 0 1 do not have factory default values Table A 59 Report Packet 5F 11 EEPROM Segment Status Report Meaning Subcode BYTE Segment Bit field Manufacturing parameters 8F 41 Status U16 Production parameters 8F 42 Receiver configuration Packet I O control Serial port configuration Timing output configuration Accurate position Self survey configuration NMEA configuration Not Used UTC information Not used 0 1 2 3 4 5 6 7 8 A 70 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x60 Command Packet 0x60 Type 1 Differential GPS Corrections This packet provides the ACE UTC GPS with differential corrections from RTCM SC 104 record types 1 and 9 in the TSIP format There is no response to this packet If bit 6 is set the corrections are as in RTCM Type 9 records The format for this packet is shown in Table A 60 Table A 60 Report Packet 0x60 Data Formats COCO 0 rarae Jos Modified z count UINT16
203. res four steps 1 Choosing a location 2 Mounting the smart antenna 3 Routing and securing the interface cable 4 Connecting the host system Each of these installation steps is described on the following pages Acutime 2000 Synchronization Kit User Guide 3 1 Acutime 2000 Installation 3 3 1 Choosing a Location Select an outdoor location for the antenna such as the roof of your building that has a relatively unobstructed view of the sky Consider the length of the cable run and the length of the interface cable when selecting a location The Acutime 2000 GPS smart antenna is designed for a pole mount The mounting pole is not included with the Acutime 2000 Pole mounting is illustrated in Figure 3 1 Figure 3 1 Mounted Antenna 3 2 Acutime 2000 Synchronization Kit User Guide 3 Acutime 2000 Installation The antenna can receive satellite signals through glass canvas and thin fiberglass but dense wood concrete and metal structures shield the antenna from satellite signals The Acutime 2000 GPS smart antenna contains an active antenna For optimal performance place it as far as possible from transmitting antennas including radars satellite communication equipment and cellular transmitters When locating the antenna near a radar installation ensure that the antenna is positioned outside of the radar s cone of transmission When installing the antenna near satellite communication equipment follow the same gui
204. ribution of the apparent clock and ephemeris prediction accuracies to the ranging accuracies obtainable with a specific satellite based on historical data Universal Coordinated Time Uniform atomic time system standard that is maintained by the US Naval Observatory UTC defines the local solar mean time at the Greenwich Meridian The difference between local time and UTC Example UTC EST 5 hours Acutime 2000 Synchronization Kit User Guide Index A abbreviations used in manual xxiii Acutime 2000 GPS Smart Antenna 12 pin connector format 4 3 communicating with 2 4 connecting 2 2 connecting host system 3 6 connection diagram 2 3 connections 4 1 enclosure illustration 1 3 installation choosing location 3 2 routing and securing interface cable 3 5 installing 2 1 3 1 interface cables and connectors 4 4 interface connector 4 3 mounting 3 4 overview 1 2 specifications D 1 start up 5 1 almanac A 40 A 58 Appendix F Theory of Operation xxi 5 1 Appendix F Theory of Operation 5 1 audience xix automatic installation Windows NT 6 16 Acutime 2000 Synchronization Kit User Guide C cable delay compensation 5 9 cautions XX1V choosing location for antenna 3 2 cold start F 3 command packets A 14 communicating with Acutime 2000 2 4 Timing Receiver Monitor 2 4 computer and power source connecting 2 3 configuration NTP software 6 1 Palisade 6 12 connecting computer and power source 2 3 connecting host system 3 6 co
205. rimble s applicable published specifications for the Software for a period of ninety 90 days starting from the date of delivery Warranty Remedies Trimble s sole liability and your exclusive remedy under the warranties set forth above shall be at Trimble s option to repair or replace any Product or Software that fails to conform to such warranty Nonconforming Product or refund the purchase price paid by you for any such Nonconforming Product upon your return of any Nonconforming Product to Trimble in accordance with Trimble s standard return material authorization procedures Warranty Exclusions and Disclaimer These warranties shall be applied only in the event and to the extent that 1 the Products and Software are properly and correctly installed configured interfaced maintained stored and operated in accordance with Trimble s relevant operator s manual and specifications and ii the Products and Software are not modified or misused The preceding warranties shall not apply to and Trimble shall not be responsible for defects or performance problems resulting from 1 the combination or utilization of the Product or Software with products information data systems or devices not made supplied or specified by Trimble 11 the operation of the Product or Software under any specification other than or in addition to Trimble s standard specifications for its products iii the unauthorized modificat
206. ronization Kit User Guide E 5 NTP Diagnostics and Debugging E COM Port Unavailable If the COM port defined in the NTP configuration file is not found or is locked by another application the following Application Event Message is generated Event Detail Byes OA This message is unique to Windows NT but the solution is based on general guidelines For more information on resolving device unavallablility see page E 16 E 6 Acutime 2000 Synchronization Kit User Guide E NTP Diagnostics and Debugging System Clock Not Set The system clock must be set close to the correct local time If NTP finds the system clock too far offset it will stop and report the following error Event Detail Byes E IYYoras Solution The sample screen below demonstrates using NTPDATE to reset UNIX system time to another NTP server The utility requires an additional b parameter behind the server name when run on Windows NT If you cannot use NTPDATE use your system s native clock function to reset the system clock Acutime 2000 Synchronization Kit User Guide E 7 NTP Diagnostics and Debugging E E 2 i xterm Al E lucky_first lucky_first date Mon May 10 00332355 PDT 1999 lucky_first lucky_first ntpdate terrapin 10 May 00 33 00 ntpdate 3768 adjust time server 155 63 31 220 offset 0 007342 sec lucky_first fj Running NTP in Debug Mode NTP can be run in debug mode as a foreground command line a
207. rovides the approximate GPS time of week and the week number to the GPS receiver The GPS receiver returns packet 4E The data format is shown below The GPS week number reference is Week 0 starting January 6 1980 The seconds count begins at the midnight which begins each Sunday morning Table A 21 Command Packet 2E fe uem Te o GPS time of week Single seconds 4 5 GPS week number Integer weeks This packet is ignored if the receiver has already calculated the time from tracking a GPS satellite 0x2 F Command Packet 2F UTC Parameters Request This packet requests the current UTC GPS time offset leap seconds The packet has no data The receiver returns packet 4F 0x31 Command Packet 31 Accurate Initial Position XYZ Cartesian ECEF Command This packet is identical in content to packet 23 This packet provides an initial position to the GPS receiver in XYZ coordinates However the GPS receiver assumes the position provided in this packet to be accurate This packet is used for satellite acquisition aiding in systems where another source of position is available and in time transfer one satellite mode applications For acquisition aiding the position provided by the user to the GPS receiver in this packet should be accurate to a few kilometers For high accuracy time transfer position should be accurate to a few meters TRAIM flags come on if this position is not accurate enough Acutime 2000 Synchronization Kit U
208. rs and should only be modified by a qualified systems administrator Create a NTP configuration file similar to the one shown in Figure 6 2 Simple NTP Configuration File for Acutime NI Trimble Acutime Smart Antenna GPS Stratum 1 server 127 127 29 1 A network time server server terrapin trimble com Figure 6 2 NTP Configuration File DX Note If your system already has a configuration file you may want to review the entries or make a backup file before modifying the existing configuration Acutime 2000 Synchronization Kit User Guide 6 11 NTP Software Installation and Configuration 6 6 5 2 Acutime Configuration The following line must be found in the NTP configuration file to declare an external Acutime NTP reference clock server 127 127 29 x The prefix 127 127 29 uniquely identifies the Acutime NTP reference clock The last number represented by x represents the reference clock unit number Unit Number The unit number identifies the physical serial port to which Acutime is connected Selection of the unit number location of the NTP configuration file and installation of the software are different for Windows NT and UNIX Follow the appropriate instructions to select the correct unit number for your Acutime Reference Clock 6 12 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 5 3 Network Server Selection To complete the co
209. rt Packet 8F 20 Continued Item Type Meaning Reserved 0 Datum Datum index 1 Fix Type BYTE Type of fix This is a set of flags 0 LSB 0 Fix was available 1 No fix available Fix is autonomous Fix was corrected with RTCM 3D fix 2D fix 2D fix used last circulated altitude 2D fix used entered altitude Unfiltered Position or altitude filter on 5 7 unused always 0 NumSVs BYTE Number of satellites used for fix Will be zero if no fix was available UTC Offset BYTE Number of leap seconds between UTC time and GPS time Week INTEGER GPS time of fix weeks Fix SVs Repeated groups of 2 bytes one for each satellite The bytes are 0 if group N A The following table describes the contents of each group lono Param The broadcast ionospheric parameters 8 CHARS 1 2 3 4 O 1 O 1 O 1 O 1 Table A 88 Report Packet 8F 20 Bytes Item Type Meaning PRNX BYTE Satellite number and IODC IODE PRN the lower six bits of PRNX IODC PRNX 64 x 256 IODE IODE BYTE Acutime 2000 Synchronization Kit User Guide A 107 Trimble Standard Interface Protocol A Ox8F 26 Report Packet 0x8F 26 Response to Save EEPROM Segments This report packet is output after the command packet 8E 26 has been executed Table A 89 Report Packet 0x8F 26 ae om Ties vob wen Subcode BYTE 0x26 1 4 Reserved ULONG 0x00 A 108 Acutime 2000 Synchronization
210. se inputs make sure that an event pulse will not occur until the time tag from the previous event pulse reported in packet Ox8F 0B or 8F AD is received 5 2 6 Cable Delay Compensation The PPS output from the Acutime 2000 is calibrated to be aligned with UTC GPS at the connector The PPS you receive is delayed by the amount of propagation delay in the cable between the Acutime 2000 and your equipment You can compensate for this delay by setting the PPS offset field of packet Ox8E 4A The propagation delay through the cable depends on the cable type used but in general the delay is approximately 1 25 nanosecond per foot of cable Negative PPS offset values cause the PPS output to occur early which compensates for the propagation delay of the cable Acutime 2000 Synchronization Kit User Guide 5 9 System Operation 5 5 3 5 3 1 5 3 2 5 10 Serial Data Communication When the Acutime 2000 has acquired a set of satellites that conforms to the mask and mode settings and has collected a valid ephemeris for each satellite it automatically commences periodic outputs of GPS data and generates a timing pulse PPS Port B The Acutime 2000 outputs periodic TSIP health mode and time messages on Port B These status messages confirm that the receiver is working These packets are described in Appendix A Trimble Standard Interface Protocol The factory default port setting is 9600 baud in out 8 data bits odd parity 1 stop bit
211. ser Guide A 27 Trimble Standard Interface Protocol A Inputting accurate position sets the self survey completion state to 100 The uploaded position is not stored in EEPROM unless it is stored with command packet 8E 26 The input position is reported by packet 8F AC A 28 Acutime 2000 Synchronization Kit User Guide 0x32 0x34 Trimble Standard Interface Protocol Command Packet 32 Accurate Initial Position Latitude Longitude Altitude Command This packet is identical in content to packet 2B This packet provides the GPS receiver with an initial position in latitude longitude and altitude coordinates However the GPS receiver assumes the position provided in this packet to be accurate This packet is used for satellite acquisition aiding in systems where another source of position is available and in time transfer one satellite mode applications For acquisition aiding the position provided by the user to the GPS receiver in this packet should be accurate to a few kilometers For high accuracy time transfer position should be accurate to a few meters TRAIM flags come on if this position is not accurate enough Inputting accurate position sets the self survey completion state to 100 The uploaded position is not stored in EEPROM unless it is stored with command packet 8E 26 The input position is reported by packet 8F AC Command Packet 34 Satellite Number For One Satellite Mode Command This packet allows the user to
212. ser Guide C 11 NMEA 0183 C C 12 Acutime 2000 Synchronization Kit User Guide D Specifications and Drawings This appendix contains the specifications for the Acutime 2000 GPS smart antenna and a diagram of the Acutime 2000 Interface Cable bX Note The interface cable specifications provided in this appendix are for the 100 foot 30 meter versions of the cables Longer versions of these cables are available The specifications for the longer cables are identical to that of the 100 foot version D 1 Acutime 2000 GPS Smart Antenna Specifications The following tables list the specifications for the Acutime 2000 GPS Smart Antenna Table D 1 Physical Specifications Dimensions 6 12 D 5 0 H 155 5mm x 127 0mm Weight 12 8 oz 363 g Connector 12 pin round waterproof Mounting 1 14 straight thread Dimensions Height 5 0 127 mm Width 6 12 155 5 mm Acutime 2000 Synchronization Kit User Guide D 1 Specifications and Drawings D Table D 2 Operating temp Environmental Specifications 40 to 85 C Storage temp 55 to 105 C Vibration 0 008 g Hz 5 Hz to 20 Hz 0 05 g Hz 20 Hz to 100 Hz 3dB octave 100 Hz to 900 Hz Operating Humidity 95 RH non condensing 60 C EMC Table D 3 General CE FCC Class B Performance Specifications L1 frequency C A code SPS continuous tracking receiver Available in 8 channel U
213. sion Acutime 2000 Block Diagram RS 422 Version Acutime 2000 Synchronization Kit User Guide 1 3 2 3 3 2 4 2 5 7 5 8 6 8 6 11 6 28 6 34 D 5 D 6 F 11 F 11 xi List of Figures xii Acutime 2000 Synchronization Kit User Guide List of Tables Table 4 1 Mating ComnectorS o 4 4 Table 4 2 Acutime 2000 RS 422 Cable Pin 00t 4 5 Table 4 3 Acutime 2000 RS 232 Cable Pin 00t 4 6 Table 5 1 Default Satellite Mask Settings 5 2 Table 5 2 Receiver Configuration segment2 5 17 Table 5 3 OEM Configuration segmentB3 5 17 Table 5 4 Port A and B Configuration segment4 5 18 Table 5 5 PPS Configuration segment 5 5 18 Table 5 6 Position Information segment 6 5 18 Table 5 7 Self Survey Configuration segment 7 5 19 Table 5 8 NMEA Configuration segment8 5 19 Table 5 9 UTC Information segment 11 5 19 Table 6 1 System Serial Ports and Symbolic Link Names 6 27 Table A 1 Ace UTC Port Translation Table A 4 Table A 2 Acutime 2000 Port Translation Table A 4 Table A 3 Secondary Port Features Acutime 2000 A 5 Table A 4 Secondary Port Features Ace UTC A 6 Table A 5 EventBacketS 00 ao gk a A ae ea a A 6 Table A 6 Packets Output at Power Up
214. st packets that have multiple Acutime 2000 Synchronization Kit User Guide A 95 Trimble Standard Interface Protocol A formats the ACE UTC GPS will broadcast only one of the formats If more than one of the formats is masked on for broadcast then the format with the greatest precision of content will be sent and the rest will not The coding for each bit in the mask follows 0 Turn off automatic output broadcast of this packet 1 Turn on automatic output broadcast of this packet A 96 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol Table A 80 Command Packet 8E A5 Byte Bit Item Type Default Description 0 Subcode UINT8 A A OxA5 2 C K JE 1 2 0 Ox8F 20 Bit 1 0 Enable 0x8F 20 output on Port 1 field 0 0 Reserved 2 0 0 Reserved 3 0 0 Reserved 4 0 0 Reserved 5 1 1 Enable auto TSIP outputs 6 0x8F AB 0 1 Ox8F AB Primary timing info on all TSIP output ports 7 Ox8F AC 0 1 Ox8F AC Supplemental timing info on all TSIP output ports 8 0x8F 0B O O Synchronous 0x8F 0B 1 Hertz on Port A Acutime 2000 only 9 Ox8F 0B 1 0 Event output of O0x8F 0B on Port A Acutime 2000 only 10 Ox8F 0B 0 0 Event output of Ox8F 0B on Port 1 11 0x8F 0B O O Synchronous 0x8F 0B on Port 1 12 0x8F AD 1 O Synchronous Ox8F AD 1 Hertz on Port A Acutime 2000 only 13 Ox8F AD 1 0 Event output of Ox8F AD on Port A Acutime 2000 only 14 0x8F AD 0 1 Event output of Ox8F
215. stallation procedures for the NTP software are below Create the Configuration File The NTP configuration file NTP CONF should be created in the WINNT directory The lines preceded by symbols are comments and are ignored by NTP El ntp Notepad olx File Edit Search Help Simple NTP Configuration File for Palisade NTP Trimble Palisade Smart Antenna GPS Stratum 1 server 127 127 29 1 A network time server server terrapin trimble com Valid unit numbers on Windows NT are 1 255 The unit number identifies the number of the serial port on the Windows NT host For example if the Acutime NTP reference clock is connected to COM2 the entry line should read server 127 127 29 2 1 Copy the sample configuration file above 2 Change the Acutime unit number to the correct number corresponding to the COM port you are using Acutime 2000 Synchronization Kit User Guide 6 17 NTP Software Installation and Configuration 6 3 Add SERVER lines for available NTP servers on your network You must add one line for each NTP server with which you want your time server to communicate 4 NTP clients should not be included in the SERVER configuration entries in the configuration file bx Note If you are using NOTEPAD to create the configuration file make sure that you select All files in the Save as type drop down menu this avoids creating a file named NTP CONF TXT which NTP will not recognize Sav
216. steering offset between the GPS DoD clock ensemble and the UTC NIST clock ensemble The large offset is the cumulative number of leap seconds since 1 January 1970 which on 31 December 1998 was increased from 12 to 13 seconds Historically the offset increases by one second approximately every 18 months usually just before midnight on 30 June or 31 December System designers should note whether the output time is UTC or GPS time bX Note The event time reported in 8F 0B and 8 AD is corrected for the fractional UTC offset if UTC PPS default is selected 5 14 Acutime 2000 Synchronization Kit User Guide 5 System Operation 5 5 Using the Acutime 2000 in Mobile Applications Although it is intended primarily for use in static applications the Acutime 2000 can also be used in mobile applications The factory default settings for the Acutime 2000 assume that the antenna is going to be used in a static timing application To use the Acutime 2000 in mobile applications you must disable the Acutime s self survey mechanism and ensure that a stored position does not exist in the nonvolatile EEPROM To prepare the Acutime 2000 for mobile applications complete the following steps Make sure that there is no stored position in the nonvolatile EEPROM by using command packet 8E 45 with data byte 1 set to 6 accurate position segment This operation clears any stored position from the EEPROM e Disable the self survey mechanism us
217. stems with minimal bandwidth for processing serial data streams the receivers can be configured as silent devices which only generate I O when polled On the other end of the spectrum the Ace UTC and Acutime 2000 receivers can be configured to output various automatic report packets and protocols to satisfy demanding real time update requirements of complex monitoring systems Event Input Both receivers feature an event input which can capture and report time stamps with the same precision as the PPS signal Primary Port Features The Acutime 2000 and Ace UTC both feature a primary bi directional port which is factory configured as for TSIP input and output Secondary Port Features Acutime 2000 The Acutime 2000 has a bi directional programmable secondary port that is designated as the Timing port The timing port s protocol input lines are shared with the Event input feature The receiver can be configured to accept protocol input or event signals but not both Acutime 2000 cannot generate event time tags 1f port A is configured for RTCM input or TSIP input The port can be configured to accept and output data using various protocols as shown in the table below Table A 3 Secondary Port Features Acutime 2000 Port Designator Input Default Output Default Port A TSIP RTCM none TSIP NMEA TSIP Acutime 2000 Synchronization Kit User Guide A 5 Trimble Standard Interface Protocol A
218. t 82 the sequence is complete and the receiver is ready to accept commands Packets Output at Power Up Description Receiver health Machine code status Software version Double precision XYZ position If single precision is selected packet 42 is output instead Double precision LLA position If single precision is selected packet 4A is output instead DGPS position fix mode A 4 Receiver Warm Start You can warm start the receiver by sending each of the following commands after the receiver has completed its internal initialization and has output packet 82 see Table Table A 7 Receiver Warm Start Commands Input ID Description 2B 23 Initial position LLA ECEF 2E Initial time 38 type 2 Almanac for each SV 38 type 3 Almanac health lonosphere page 38 type 4 38 type 5 UTC correction Acutime 2000 Synchronization Kit User Guide A 7 Trimble Standard Interface Protocol A A 5 Default Background Packets for Acutime 2000 The Acutime 2000 automatically outputs a set of packets that you can monitor for changes in receiver operations including receiver health time almanac pages and ephemeris updates These messages are output at the rates indicated in the table below Table A 8 Background Packets Output ID Description GPS time If the receiver s GPS clock is set and the receiver is not outputting positions time is output ap
219. t 8E 4D 0x8E 26 Command Packet 8E 26 Write Receiver Configuration to EEPROM This command packet causes the current configuration settings to be written to the EEPROM It also generates a report packet 8F 26 This packet contains only a single byte the subpacket ID 0x8E 41 Command Packet 8E 41 Manufacturing Operating Parameters This packet is used to request the manufacturing parameters stored in nonvolatile memory The packet contains only a single byte the subpacket ID The receiver returns packet 8F 41 Acutime 2000 Synchronization Kit User Guide A 89 Trimble Standard Interface Protocol A 0x8E 42 Command Packet 8E 42 Production Parameters This packet is used to request the production parameters stored in nonvolatile memory This packet contains only a single byte the subpacket ID The receiver returns packet 8F 42 0x8E 45 Command Packet 8E 45 Revert Segments to Default Settings This command packet reverts the parameters stored in a specific EEPROM segment or all segments to their factory default settings and reconfigures the ACE UTC GPS using those settings The receiver returns packet 8F 45 Table A 74 Command Packet 0x8E 45 Segment Description Subcode Segment Receiver configuration number Packet I O control Serial port configuration Timing output configuration Accurate position Self survey configuration NMEA configuration UTC information Segments 2 through 8 All segments
220. t is the primary timing output generated by the Acutime 2000 In all configurations of the product the PPS output is provided through a RS 422 differential driver Although using a RS 422 differential receiver to receive the PPS provides the best noise immunity you can use just one side of the differential signal for single ended applications You can program the characteristics of the PPS output using TSIP packets Packet 0x8E 4A allows you to enable or disable turn it on or off control the polarity select the time base GPS or UTC and set the offset control the cable delay compensation of the PPS output Packet Ox8E 4E allows you to set an accuracy criterion for the generation of the PPS signal based on the number of usable satellites The accuracy of the PPS output depends to some degree on the number of satellites used in the solution that determine the placement of the PPS output In some systems it is preferable to have the PPS generated only when it meets the highest levels of accuracy and to leave it off if these accuracy levels are not met Packet 0x8E 4F allows you to select the width of the PPS output from 10 us to 500 ms Note For a complete description of the packets described here see Appendix A Trimble Standard Interface Protocol Acutime 2000 Synchronization Kit User Guide 5 System Operation 5 2 4 PPS Quantization Error The Acutime 2000 uses a high precision fixed frequency oscillator as the timing source to
221. tch sets the threshold for automatic 3 D 2 D mode If 4 or more satellites are available and the resulting PDOP is not greater than the PDOP mask value then 3 dimensional fixes are calculated This information is stored in non volatile memory Report Packet 4C Type Units Default Value Velocity Dynamics code 0 value left unchanged 1 land lt 120 knots 2 sea lt 50 knots 3 air lt 800 knots 4 static stationary Elevation angle SINGLE mask radians Signal level mask SINGLE PDOP mask SINGLE A 52 PDOP switch SINGLE 3 D or 2 D Acutime 2000 Synchronization Kit User Guide 0x4D 0x4E Trimble Standard Interface Protocol Report Packet 4D Oscillator Offset This packet provides the current value of the receiver master oscillator offset in Hertz at carrier This packet contains one SINGLE number 4 Bytes The receiver sends this packet in response to packet 2D Report Packet 4E GPS Time Change Acknowledgment Indicates whether the receiver accepted the time given in a Set GPS time packet The receiver sends this packet in response to packet 2E This packet contains one byte Table A 44 Report Packet 4E Value Meaning ASCII Y The receiver accepts the time entered via packet 2E The receiver has not yet received the time from a satellite ASCII N The receiver does not accept the time entered via packet 2E The receiver has received the time fro
222. tched to GPS time by sending the appropriate TSIP command F 4 2 NMEA 0183 The NMEA 0183 protocol supports only LLA format and UTC time If a custom datum is required it can be set through TSIP using command 0x8E 15 Acutime 2000 Synchronization Kit User Guide F 7 Theory of Operation F F 5 Performance Characteristics This section lists performance information for the Acutime 2000 F 5 1 Update Rate The Acutime 2000 updates position at one second intervals during self survey The surveyed position is frozen after the survey completes F 5 2 Dynamic Limits The dynamic operating limits for the various receiver designs are listed below These operating limits assume that the smart antenna is correctly installed and that the overall system is designed to operate under the same dynamic conditions Table F 1 Dynamic Upper Bound Dynamic Operating Limits Velocity 500 m s Acceleration 4g 39 2 m s Jerk 20 m s F 5 3 Re Acquisition When a satellite signal is momentarily interrupted during normal operation the receiver continues to search for the lost signal at the satellite s last known Doppler frequency If the lost signal is not re acquired within 15 seconds the receiver initiates a broader frequency search The smart antenna uses the last known information about the dynamics of the receiver and the satellite to establish the center frequency and range for the search Every 15 seconds until the lost si
223. teger leap second offset between GPS and UTC according to the relationship Time UTC Time GPS UTC Offset The UTC offset information is reported to ACE UTC GPS by the GPS system and can take up to 12 5 minutes to obtain Before the ACE UTC GPS has received UTC information from the GPS system it is only capable of representing time in the GPS time scale and the UTC offset will be shown as 0 Timing Flags This field is bitwise encoded to provide information about the timing outputs Unused bits should be ignored Bit 0 When 0 the date and time fields broadcast in packet Ox8F AB are in the GPS time scale When 1 these fields are in the UTC time scale and are adjusted for leap seconds Bit 2 When 0 time has been set from GPS When 1 time has not yet been set from GPS Bit 3 When 0 UTC offset information has been received When 1 UTC offset information is not yet known Time of Day The time of day is sent in hours minutes seconds format and varies from 00 00 00 to 23 59 59 except when time is in UTC and a leap second insertion occurs In this case the time will transition from 23 59 59 to 23 59 60 to 00 00 00 Date The date is sent in day month year format Acutime 2000 Synchronization Kit User Guide Trimble Standard Interface Protocol Table A 96 Report Packet 0x8F AB Byte Bit Item Type Value Meaning 0 Subcode BYTE 0xAB 1 4 Time of ULONG GPS seconds of week week 5 6 Week UIN
224. terproof UV resistant plastic polycarbonate enclosure with a proven epoxy seal The enclosure is illustrated in Figure 1 1 Figure 1 1 Acutime 2000 GPS Smart Antenna Enclosure Acutime 2000 generates a PPS synchronized to UTC within 50 nanoseconds one sigma This level of precision is obtained using an overdetermined time solution an 80 nanosecond pulse steering resolution and a T RAIM Time Receiver Autonomous Integrity Monitor algorithm The Acutime 2000 s PPS conforms to RS 422 which supports long cable runs The Acutime 2000 outputs a comprehensive time packet after each PPS on a dedicated serial port It also features an automatic operating mode that requires no user or host intervention The Acutime 2000 accepts an event input and reports time stamps in response to an external event signal The Acutime 2000 is available in the following configurations e Acutime 2000 with RS 422 Interface and 8 channel receiver Acutime 2000 with RS 232 Interface and 8 channel receiver Acutime 2000 Synchronization Kit User Guide 1 3 Introduction 1 3 Starter Kit The Acutime 2000 Synchronization Kit includes the following Acutime 2000 with RS 422 interface and 8 channel receiver Acutime 2000 User Guide 100 interface cable with DB25 connectors RS 422 to RS 232 converter Timing Receiver Monitor software Power Supply For information about Acutime 2000 interface cables see Chapter 4 Acutime 2000 Connections For inf
225. ters is limited to 74 characters or less Acutime 2000 Synchronization Kit User Guide C 3 NMEA 0183 C C 3 NMEA 0183 Message Options The Acutime 2000 can output any or all of the messages listed in Table C 2 When NMEA is chosen its default configuration as shipped from the factory outputs two messages GGA and VTG These messages are output at a one second interval with the GP talker ID and checksums DX Note The user can configure a custom mix of the messages listed in Table C 2 See Port A Timing page 5 10 and TSIP command packets OxBC 0x7A and 0x8E 0x26 in Appendix A Trimble Standard Interface Protocol for details on configuring NMEA output PN Warning If too many messages are specified for output you may need to increase the unit s baud rate Table C 2 Acutime 2000 NMEA Messages Setting Message Description Default GGA GPS fix data NMEA Version 2 1 GLL Geographic position Latitude Longitude GSA GPS DOP and active satellites GSV GPS satellites in view RMC Recommended minimum specific GPS Transit data Default VTG Track made good and ground speed ZDA Time amp Date C 4 Acutime 2000 Synchronization Kit User Guide C NMEA 0183 C 4 NMEA 0183 Message Formats The format for each message is described in more detail in the following sections C 41 GGA GPS Fix Data The GGA message includes time position and fix related data for the GPS receiver SGP
226. the leap second takes place The Leap Pending bit indicates that the leap second will be inserted at the end of the current day The GPS Leap Warning bit is set while GPS is operating in the leap exception mode specified in ICD 200 The Leap in Progress bit is set to 1 at the beginning of the leap second and cleared at the beginning of the second following the leap event The date rollover is delayed by one second on the day the leap second is inserted The date will not increment until the beginning of the first second following the leap second Table A 100 Leap Second Flag Definitions Meaning if set to 1 UTC Flag UTC Time is available Reserved N A Leap Scheduled GPS Almanac s leap second date is not in the past Leap Pending 24 hour warning Cleared before leap second GPS Leap Warning Set 6 hours before after leap event Leap in Progress Leap second is now being inserted Acutime 2000 Synchronization Kit User Guide A 125 Trimble Standard Interface Protocol A 18 Datums The table on the following pages lists datums Table A 101 Datums 6378137 000 Eccentricity 0 00669437999014 Description I NGS 84 637797 155 0 00667437311265 Tokyo from old J6 values 6378206 400 0 0067865799761 NAD 27 6378206 400 0 00676865799761 Alaska Canada 6378388 000 0 00672267002233 European 6378160 000 0 00669454185459 Australian
227. tification codes the format of each packet and all available information that can be output from the Ace UTC and Acutime 2000 This manual allows the user to configure the receiver to output information required for a particular application The receiver transmits some of the information position and velocity solutions etc automatically when it is available while other information is transmitted only on request A 2 Physical Interface Characteristics The Ace UTC and the Acutime 2000 utilize high quality serial I O components to drive the available serial transmit and receive channels The Acutime 2000 is available in RS 232 and RS 422 configurations while the Ace UTC utilizes single ended technology the proven in a long series of embedded board level receiver products Regardless of the physical transmission medium the receiver architectures allow both products to achieve identical performance while the firmware offers a proven standardized interface The Ace UTC s I O capabilities differ from those of Acutime 2000 as a result of physical differences between the two boards Some options in the serial port configuration packet OxBC are not applicable to either Ace UTC or Acutime 2000 and are labeled as such This section is provided to provide the user with a complete understanding of the capabilities of each receiver Acutime 2000 Synchronization Kit User Guide A 3 Trimble Standard Interface Protocol A A 4 A 2 1 A
228. ting from radians to degrees using an insufficiently precise approximation for the constant 7 Pi introduces significant and readily visible errors The value of TT as specified in ICD GPS 200 is 3 1415926535898 Acutime 2000 Synchronization Kit User Guide A 77 Trimble Standard Interface Protocol A 0xBB A 78 Command Packet BB Set Primary Receiver Configuration TSIP command packet BB contains the primary receiver configuration parameters The Ace UTC and Acutime 2000 store 3 independent sets of configuration parameters These are designated as the Mobile Survey and Timing configurations The active configuration is determined by the survey state Table A 67 Survey State Configurations Survey State Active Configuration Survey Disabled Mobile Survey Active Survey Survey Complete Timing When the survey state changes the receiver automatically switches to the new configuration Only the active configuration can be programmed To program configurations switch the active configuration by changing to the appropriate survey state using packets 8E A6 and 8E A9 update the configuration BB and save settings 8E 26 There are restrictions to the dynamics code and operating dimension settings which take effect when survey is enabled ensuring that the receiver performs a valid survey and enters a timing mode afterwards The following table shows valid settings for each configuration Acutime 2000 Synchronization
229. tion TSIP report packet BB is used to report the GPS Processing options For information about the data formats see command packet BB Command Packet BC Set Port Configuration Parameters TSIP command packet BC is used to set the communication parameters on Port 1 and Port 2 The table below lists the individual fields within the BC packet Flow control is not supported Please refer to section A 2 Physical Interface Characteristics for details on the capabilities of each port on the Ace UTC and Acutime 2000 Command Packet BC Value Meaning Default Port 2 Port B Port 1 Port A current port Type Rate Input Baud None 110 baud 300 baud 600 baud 1200 baud 2400 baud 4800 baud 9600 baud 19200 baud 38400 baud Output Baud Rate As above Acutime 2000 Synchronization Kit User Guide Data Bits 7 bits 8 bits A 83 Trimble Standard Interface Protocol A Table A 70 Command Packet BC Continued Meaning Default None Odd Even 1 bit 2 bits 0 none Parity Stop Bits reserved none TSIP RTCM Port 2 only none TSIP NMEA None Input Protocols Output Protocols O PR NO ONOJO NO N gt O Reserved 0xBC Report Packet BC Request Port Configuration Parameters TSIP packet BC is used to request the communication parameters on Port 2 and Port B To query a port s configuration parameters send pa
230. tion Kit User Guide A 21 Trimble Standard Interface Protocol A 0x20 Command Packet 20 Almanac Request This packet requests almanac data for one satellite from the GPS receiver This packet contains one data byte specifying the satellite PRN number The GPS receiver returns packet 40 hex 0x21 Command Packet 21 Current Time Request This packet requests current GPS time This packet contains no data The GPS receiver returns packet 41 hex 0x23 Command Packet 23 Initial Position XYZ Cartesian ECEF Command This packet provides the GPS receiver with an approximate initial position in XYZ coordinates This packet is useful 1f the user has moved more than about 1 000 miles since the previous fix bX Note The GPS receiver can initialize itself without any data from the user this packet merely reduces the time required for initialization This packet is ignored if the receiver is already calculating positions The origin is the earth s center The X axis points toward the intersection of the equator and the Greenwich meridian the Y axis points toward the intersection of the equator and the 90 meridian and the Z axis points toward the North Pole The cold start default LLA not XYZ position is 0 0 0 The data format is shown in the table below Table A 19 Command Packet 23 A 22 Acutime 2000 Synchronization Kit User Guide 0x24 0x25 0x26 Trimble Standard Interface Protocol Table A 19 Command Packet 2
231. tocol A 0x5B A 66 Time of measurement The time of measurement Byte 17 is the center of the sample interval adjusted by adding the receiver supplied codephase modulo mS to a user determined integer number of mS between user and satellite The receiver codephase resolution is 1 16th of a C A code chip This corresponds to 1 16 X C A code chip 977 517ns 16 61 0948 ns Y 61 0948 X speed of light m s 18 3158 meters Y The integer millisecond portion of the pseudo range must then be derived by utilizing the approximate user and satellite positions Rough user position within a few hundred kilometers must be known the satellite position can be found in its almanac ephemeris data Each mS integer corresponds to C A code epoch X speed of light 1msX speed of light m s Y 300 km approximate 299 792458 km precise Y The satellite time of transmission for a measurement can be reconstructed using the code phase the time of measurement and the user determined integer number of milliseconds Report Packet 5B Satellite Ephemeris Status Report This packet is sent in response to packet 3B and optionally when a new ephemeris based on IODE is received It contains information Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol on the status of the ephemeris in the receiver for a given satellite The structure of packet 5B is shown in the table below Table A 57 Report P
232. ts the GPS system ASCII message sent with the navigation data by each satellite This packet contains no data The GPS receiver returns packet 48 Command Packet 29 Almanac Health Page Request This packet requests the health page from the almanac This packet contains no data The GPS receiver returns packet 49 Command Packet 2A Altitude for 2 D Mode Command This packet provides the altitude to be used for Manual 2 dimensional navigation mode This altitude is also used for Auto 2 D mode This packet contains one SINGLE number 4 bytes specifying the altitude in meters using the WGS 84 model of the earth or MSL geoid altitude depending on I O options set by packet 35 The GPS receiver returns packet 4A It is recommended that the user upload the reference altitude before the receiver starts doing position fixes If an altitude is not provided the receiver will use the altitude of the previous 3 D fix altitude hold mode Sending packet 2A with one data byte equal to OxFF will cancel altitude set mode and return the reference altitude to 0 The altitude setting is stored in non volatile memory Packet 0x8E 26 can be used to write receiver configuration to EEPROM Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol To use the fixed altitude survey mode the receiver must be configured to Manual 2 D navigation mode using packet BB The reference altitude will be used in 2 D survey from both warm and
233. ulse input is supported on Port A pins 6 and 7 The Acutime 2000 transmits a TSIP time packet 8Fx0B or 8FxAD in response to the event input The TSIP packet increments the event count field for each event received The event time stamp is generated within 320 nanoseconds of arrival at the Acutime 2000 s interface connector The precision of the time stamp is subject to Selective Availability Acutime 2000 Synchronization Kit User Guide 4 9 Acutime 2000 Connections 4 bX Note These Port A pins are shared between the external event input and serial RTCM message inputs When differential GPS is enabled this input is set up to receive RTCM messages When differential GPS is off this input is set up to receive external event signals 4 10 Acutime 2000 Synchronization Kit User Guide 5 System Operation This chapter describes the operating characteristics of the Acutime 2000 GPS smart antenna including start up satellite acquisition operating modes serial data communication and the timing pulse The Acutime 2000 acquires satellites and computes position and time solutions It outputs data in the TSIP or NMEA protocol through its serial ports For more technical information on system operation see Appendix F Theory of Operation 5 1 Start Up At power up the Acutime 2000 automatically begins to acquire and track GPS satellite signals It typically obtains its first fix in under two minutes During the satellite
234. user with administrator privileges Note Other third party distributions of NTP for Windows NT may not support the Acutime NTP reference clock X Note Not all features documented in the UNIX Version of NTP are supported in the Windows NT port Trimble makes every effort to maintain the Windows NT port at the highest performance levels but cannot maintain complete compatibility with UNIX versions or provide technical support on the NTP port beyond the online documentation X Acutime 2000 Synchronization Kit User Guide 6 15 NTP Software Installation and Configuration 6 16 6 6 1 Automatic Installation The automatic installation program for Windows NT performs all the steps required to install and configure the Network Time Protocol Service for Windows NT with minimal input from the user For detailed installation instructions please refer to the documentation accompanying the NTP installation program The installation program creates the NTP configuration file after allowing the user to input the names or IP numbers of Network Time Servers and information about the Acutime NTP reference clock Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 6 2 Manual Installation Manual installation requires the user to create the configuration file copy the NTP executable to the appropriate location on disk and then install configure and start the NTP service The manual in
235. utable you choose Acutime 2000 Synchronization Kit User Guide 6 29 NTP Software Installation and Configuration 6 6 7 5 System Initialization Some systems may require additional initialization before NTP can run Sun OS and Solaris may require running the TICKADJ utility to turn off synchronization with the onboard real time clock 4 xterm Iof ES lucky_first lucky_first lucky_first cat etc motd Sun Microsystems Inc SunOS 5 5 Generic November 1995 lucky_first lucky_first lucky_first tickadj s KERNEL nsec_per_tick 10000000 nsec KERNEL tick 10000 usec from nsec_per_tick kernel variable PRESET tick 10000 usec PRESET tickadj 5 usec dosynctodr is off kernel level printf st on KERNEL hz 100 calculated hz 100 00 Hz zeroing dosynctodr done lucky_first lucky_first lucky_first 6 30 Acutime 2000 Synchronization Kit User Guide 6 NTP Software Installation and Configuration 6 7 6 Start NTP Execute NTP from the command line by typing the path and name of the ntp executable usr local bin ntpd Installation of NTP is complete You still need to modify startup scripts to ensure NTP is loaded when the system reboots To verify the correct operation of NTP and the Acutime NTP reference clock follow the instructions in the next section Monitoring NTP To diagnose possible problems communicating with the Acutime see Appendix E NTP Diagnostics and Debugging 6 8 Monitoring NT
236. utime 2000 Synchronization Kit User Guide A 19 Trimble Standard Interface Protocol A A 15 Packet Descriptions Command packets are sent from an external device such as a computer or terminal to the receiver when requesting report packets setting receiver parameters or performing receiver command operations such as resetting the receiver Many command packets have a corresponding report packet which is sent to the external device in response to the command packet Some commands perform discrete operations and have no matching report packet 0x1 D Command Packet 1D Oscillator Offset This packet commands the GPS receiver to set or clear the oscillator offset in battery backed memory This is normally used for servicing the unit Table A 16 Command Packet 1D Clear Oscillator Offset Bye nem Type value Response JO Operation Byte C 43 hex Clear the oscillator offset To set the oscillator offset four data bytes are sent the oscillator offset in Hertz relative to L1 as a SINGLE real value The oscillator offset is automatically updated when the receiver is doing fixes Table A 17 Command Packet 1D Set Oscillator Offset exe em Type vate CA 0 3 Offset Single Offset in Set the oscillator offset Hertz DX Note Use of this packet is for diagnostic purposes only and is not recommended for the user A 20 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x1 E Command
237. ver returns packet 5B if data is available Table A 26 Command Packet 3B Texte vem pe vate weaning 1 Satellite Byte 0 All satellites for which ephemeris data is available 1 32 Desired satellite A 38 Acutime 2000 Synchronization Kit User Guide A Trimble Standard Interface Protocol 0x3C Command Packet 3C Satellite Tracking Status Request This packet requests the current satellite tracking status The GPS receiver returns packet 5C 1f data is available Table A 27 Command Packet 3C exe vom Type vane Weoning O Satellite Byte 0 All satellites in the current tracking set 1 32 Desired satellite Acutime 2000 Synchronization Kit User Guide A 39 Trimble Standard Interface Protocol A 0x3D Command Packet 3D Timing Port Configuration Command This packet is superceded by 0xBC 0x3F 1 1 Command Packet 3F 11 EEPROM Segment Commands This command packet requests the status of the EEPROM segments and clears the EEPROM status minor alarm bit Bit 10 in the supplemental timing packet 8F AC The ACE UTC replies with report packet 5F 11 Table A 28 Command Packet 3F 11 Bye tem vpe vete Meaning o fewo eve o EEPROM segment saus 0x40 Report Packet 40 Almanac Data Page Report This packet provides almanac data for a single satellite The GPS receiver sends this packet on request packet 20 hex and optionally when the data is received from a satellite The data format is shown below Table
238. warm start one of the channels is directed in a cold start search This strategy minimizes the time to first fix in cases where the stored almanac position and time are invalid If the cold start search proves effective and the garage search fails the stored information is flushed from memory F 2 4 Hot Start A hot start strategy applies when the almanac position time and ephemeris in memory are valid The hot start search strategy is similar to a warm start but since the ephemeris data in memory is considered current and valid the acquisition time is typically less than 30 seconds This may occur if the GPS signals are temporarily obscured or jammed Acutime 2000 Synchronization Kit User Guide F 5 Theory of Operation F F 3 F 3 1 F 6 Position Accuracy GPS position accuracy is degraded by atmospheric distortion satellite and receiver clock errors and Selective Availability S A Effective models for atmospheric distortion of satellite signals have been developed to minimize the impact of tropospheric and ionospheric effects The impact of satellite clock errors is minimized by incorporating the clock corrections transmitted by each satellite used in the position solution S A is the most significant contributor to position error and cannot be effectively counteracted except with differential GPS Selective Availability S A The U S Department of Defense through a program called Selective Availability intentionall
239. y at the risk of lowering the fix density Note The receiver may require an initial position fix before switching to some modes Command Packet BB Meaning Default configuration block Operating Automatic Full Position Dimension Time only 1 SV Horizontal 2D Full position 3D DGPS reference 2D clock hold Overdetermined clock DGPS Mode DGPS off DGPS Auto DGPS only DGPS auto Dynamics Land lt 120 knots Code Sea lt 50 knots Air lt 800 knots Static Acutime 2000 Synchronization Kit User Guide A 81 Trimble Standard Interface Protocol Table A 69 Command Packet BB Continued Solution Mode Meaning Overdetermined fix Default Over determined fix Elevation Mask SINGLE Lowest satellite elevation for fixes 0 1745 10 deg AMU Mask SINGLE Minimum signal level for fixes 4 0 PDOP Mask SINGLE Maximum PDOP for fixes PDOP Switch SINGLE Selects 2D 3D mode DGPS Age BYTE Maximum time to use a DGPS correction seconds 30 seconds Foliage Mode Never Reserved N A Reserved N A Measurement Rate 1 Hertz Position Fix Rate 1 Hertz Reserved A 82 Reserved for future use Acutime 2000 Synchronization Kit User Guide 0xBB 0xBC Table A 70 Item Port Number Trimble Standard Interface Protocol Report Packet BB Report Receiver Configura
240. y degrades GPS accuracy for civilian users The S A program creates position errors by modifying the apparent position of each satellite and introducing random dither into each satellite s clock In extreme cases all sources of error natural PDOP and S A can combine to produce large position errors The DOD s definition of accuracy under S A is 100 meters 2 dRMS horizontal two dimensional 95 percent of the time Acutime 2000 Synchronization Kit User Guide F Theory of Operation F 4 Coordinate Systems This section lists the coordinate system formats supported by the TSIP and NMEA 0183 protocols F 4 1 TSIP In the default TSIP configuration position is output in a Latitude Longitude Altitude LLA format based on a default datum WGS 84 The LLA format can be easily converted by the host system to other coordinate systems using the appropriate translation algorithm By sending the appropriate TSIP command the smart antenna s position output can be changed to a Cartesian XYZ coordinate format The datum used for LLA transformations can also be changed using the TSIP 8E packet The smart antenna offers a selection of 179 datums which are listed in Appendix A Trimble Standard Interface Protocol The TSIP velocity output format is also three dimensional The default format is X Y Z with the option of an East North Up ENU coordinate format Time tags on fix messages default to UTC Universal Coordinated Time but can be swi
241. y track a satellite down to near the horizon However when this mask is set too low the receiver may experience frequent constellation switching due to low elevation satellites being obscured Acutime 2000 Synchronization Kit User Guide A 79 Trimble Standard Interface Protocol A A 80 Frequent constellation switching is undesirable because position jumps may be experienced when Selective Availability is present and DGPS is not available to remove these effects The benefit of a low elevation mask is that more satellites are available for use in a solution and a better PDOP may be yielded The current default mask is set to 0 1745 radians 10 and provides a reasonable trade off between the benefits and drawbacks Signal Level Mask This mask defines the minimum signal strength for a satellite used in a solution There is some internal hysteresis on this threshold which allows brief excursions below the threshold if lock is maintained and the signal was previously above the mask This mask should be lowered only with caution since it is also used to minimize the effects of jammers and reflected signals on the receiver Users who require high accuracy can use a slightly higher mask of 6 0 8 0 since weaker measurements may be noisier and are often caused by reflected signals which provide erroneous ranges Make sure that the elevation and SNR masks are not set too low The satellite geometry is sometimes improved considerably by select
242. ystem the device name would refer to a device such as COM1 Possible Problems The configured serial port is not actually present on the system Solution Edit the configuration file and select a valid serial port The link to the actual UNIX device file is incorrect Solution Delete and re link the UNIX serial device using the procedures outlined in Set Up Device Links page 6 26 Acutime 2000 Synchronization Kit User Guide NTP Diagnostics and Debugging Other services or applications are attempting to use the same port as NTP Solution Reconfigure NTP or the conflicting application to resolve the conflict E 3 Compiling the NTP Distribution To obtain compatibility updates download the latest published versions of the Acutime NTP reference clock I O module and associated documentation from ftp ftp trimble com pub ntp Palisadedrv If you cannot locate a copy of an NTP executable for your system that supports Acutime you can download and compile NTP yourself You will need to build NTP on a system with a compiler l Download the current version of NTP to your working directory Use GZIP to uncompress the NTP distribution archive file gzip d ntp 4 xx xx tar gz Unpack the archive file using tar xf ntp 4 xx xx tar A directory named NTP 4 XX XX will be created in your working directory Change to the new directory cd ntp 4 xx xx NTP is distributed with an automatic configuration utility Acut

Trimble Outdoors 45005-00-ENG User's Manual

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