Home

Trimble Outdoors SK8 GPS Receiver User Manual

Contents

1. OXX6L782 Jld ig Y 1101 Es NWO TVIS JON 4 SNOXX 6L482 ma SN BAST 775000 g jh i OMG NUY 179 sian HAT TL SOND Sdd 9 SYNOHI 9 wan UU j iid ya my BAIT TI SORO VOU t E MEIN T
2. 17 A 15 3 Elevation Mask o ol db RR SR A 17 A 15 4 SignalbevelMasK mioa vss sot woo eed e a a A 18 A 15 5 DOP Mask and Switch A 18 vii viii A 16 A 17 A 15 6 Packet OXBB Set DGPS A 19 Packet Structure i uos o eos hid Ue etu Sd inn d estetica ive A 19 Packet Descriptionss x dedu mg ROE hh xe Cie Ae Gok A 20 A 17 Command PacketOxID es A 20 17 2 Command Packet ORTE cee s nono Bed ow oe AU A 20 A 17 3 0 A 20 A 17 4 Command PacketOx21 2 ee A 20 A 17 5 CommandPacketOx23 2er A 21 A 17 6 0 24 A 21 A 17 7 Command Packet 0x25 2 e 21 A 17 8 Command Packet 0 26 0 21 A 17 9 0 27 21 A 17 10 Command Packet 0x28 2 222 21 A 17 11 Command Packet 0OX2A 2s sos a es ae 22 A 17 12 0 2 23 17 13 Command Packet OID o co iona e E 23 A 17 14 Command Packet OX2E 23 17 15 0 31
3. 24 A 17 16 Command Packet 0x32 5 2 24 AILIS Command Packet 0X35 3 0 6 24 A 17 18 0 37 26 A 17 19 Command Packet 0 38 A 27 A 17 20 Command Packet 0x39 A 28 A 17 21 0 3 A 28 17 22 Report Packet 0 41 eA A 29 A T 7223 Packet 0x42 ete voc at ne ober eet nas A 30 A724 Report Packet 0x43 i A dre e A 30 A 17 25 0 45 A 31 A 17 26 Report Packet 0X46 2 2 4b soa E dee ed Pow ee A 32 A27 ReportPacketOx4 4 4439 Ro A Ra EA Gok b ee dee SS A 33 A 17 28 0 48 A 33 A 17 29 Report Packet OX4A amp dons sete Sed e ee A 33 A 17 30 Main Ox4A Report Packet Type lee A 34 A 17 31 Second Ox4A A 34 Reference Altitudes 4 5 doe ee BO a A A 34 Altitude Flagi na A Bon he Rs A Good DRE SI A A 35 17 32 0 4 A 35 A 17 33 R port PacketOx4D fod eoo ee ern wee ted A 36 A 17 34 Report Packet OXAE 2 uo eS Oa ee deus A 36 Lassen SK8 Embedded GPS Module A
4. A 55 A 17 53 0 7 A 56 A17 54 Report Packet 0X82 uude EUR UR ek od A 56 A 17 55 0 83 A 57 A 17 56 0 84 A 57 AAT SS Report Packet 0x85 doe owe es wee sedere d A 58 A 17 58 50 8 0 8 A 58 A 17 59 0 A 59 A 17 60 ReportPacket OXBB 0000000000020 A 60 A 17 61 CommandPacketOXBC eA A 60 A 17 62 0 A 61 A 18 TSIP Superpackets sare dh i do V ea A Regex Re A 62 A 18 1 Command Packet Ox8E 15 Set Request Datum A 62 18 2 0 8 19 A 64 A 18 3 0 8 20 A 64 A 18 4 0 8 26 A 65 A 18 5 Report Packet Ox8F 15 Current Datum Values A 65 A 18 6 Report Packet Ox8F 17 eA A 66 Lassen SK8 Embedded GPS Module ix 18 7 0 8 18 A 66 A 18 8 Report Packet Ox8F 19 2 2 ee A 67 A 18 9 Report Packet Ox8F 20 2 lee A 67 A 18 10 0 8 26 A 69 Datum sh us dt o etus e
5. 41 Report Packet 0x58 Ionosphere 42 Report Packet 0x58 UTC Data ees A 42 Report Packet 0x58 Ephemeris A 42 Report Packet 0x59 Data A 44 Report Packet OxSA Data A 45 Report Packet OxSC Data A 47 Report Packet 0x60 Data Formats A 48 Report Packet 0x60 Data Formats for Health and Power A 48 Command Packet 0x61 Data Formats A 49 Report Packet Ox6D Data A 50 Set Synchronized Measurement A 51 Request Synchronized Measurement Parameters A 51 Set Synchronized Measurement Parameters A 52 Synchronized Measurements A 52 FLAGSI Bit Assignments 53 Command and Report Packet 0x70 Field Descriptions A 54 Command Packet 0x7A Data A 55 Lassen SK8 Embedded GPS Module Table A 62 55 Table A 63 Table A 64 Table A 65 Table A 66 Table A 67 Table A 68 Table A 69 Table A 70 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
6. A 50 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 17 47 Command Packet Ox6E Set or Request Synchronized Measurement Parameters Packet 6E sets or requests the Synchronized Measurement parameters The synchronized measurement parameters are sent by the GPS receiver in Packet Ox6F Enable Disable Synchronized Measurements Controls whether synchronized measurements will be output at the output interval Note Synchronized Measurement outputs will only be available after the GPS receiver has made a position fix once the receiver is turned on or reset by Command Packet 0x25 This ensures that information within the Synchronized Measurement packet will be valid Output Level The period of the Synchronized Measurement outputs is synchronized to the GPS time of the week For example outputs occur when the GPS time of week equals INT N where INT is the selected output interval and N is an integer Two forms of this packet are shown in Table A 54 and Table A 55 The response for both forms of this packet is Packet Ox6E Synchronized Measurement Parameters Table A 54 Set Synchronized Measurement Parameters Item Meaning Subcode Synchronized measurement Parameters Enable Disable outputs Enable Outputs Output Interval Output interval in seconds synchronized to the GPS time of week Table A 55 Request Synchronized Measurement Parameters Byte Ite
7. Lassen SK8 Embedded GPS Module A 69 Trimble Standard Interface Protocol A 19 Datums Datum selections are not available for version 7 52 firmware Table A 85 Datums A axis Eccentricity Description 6378137 000 0 00669437999014 WGS 84 6377397 155 0 00667437311265 Tokyo from old J6 values 6378206 400 0 00676865799761 NAD 27 6378206 400 0 00676865799761 Alaska Canada 6378388 000 0 00672267002233 European 6378160 000 0 00669454185459 Australian 6378135 000 0 00669431777827 l WGS 72 6378137 000 0 00669438002290 NAD 83 oO 2 OINI oO 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 U S Navy 6378388 000 0 00672267002233 European 6378160 000 0 00669454185459 Australian 1984 6378249 145 0 00680351 128285 Adindan Mean 6378249 145 0 00680351 128285 Adindan Ethiopia 6378249 145 0 00680351 128285 Adindan Mali 6378249 145 0 00680351 128285 Adindan Senegal 6378249 145 0 00680351 128285 Adindan Sudan 6378245 000 0 00669342162297 Afgooye Somalia 6378388 000 0 00672267002233
8. gt SRTSAVE_CONFIG lt Lassen SK8 Embedded GPS Module C 21 Trimble ASCII Interface Protocol TAIP C 20 ST Status Data String Format AABCDDEFGG Note This message provides information about the satellite tracking status and the operational health of the sensor This information is contained in five status bytes which are output as five 2 digit hexadecimal values The data format and the meanings of the hex characters are given in the following tables Table C 20 Data String Hex Characters Item of Char UNITS Format Tracking Status Code 2 n a AA see table below Status Codes Nibble 1 1 n a B see table below Status Codes Nibble 2 1 n a see table below Machine ID 2 n a DD Status Codes Nibble 3 1 n a E not currently used Status Codes Nibble 4 1 n a F see table below reserved 2 n a GG not currently used Table C 21 Tracking Status Code Value AA Meaning 00 Doing position fixes 01 Don t have GPS time yet 02 Not used 03 PDOP is too high 08 No usable satellites 09 Only 1 usable satellite 0 Only 2 usable satellites 0B Only 3 usable satellites 0C 6 Ch units only the chosen satellite is unusable DX Note In the tables below an X in a column means that fault is being reported C 22 Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP Table
9. Ain El Abd Bahrain 6378160 000 0 00669454185459 Anna 1 Astro 1965 6378249 145 0 00680351 128285 Arc 1950 Mean 6378249 145 0 00680351 128285 Arc 1950 Botswana 6378249 145 0 00680351 128285 Arc 1950 Lesotho 6378249 145 0 00680351 128285 Arc 1950 Malawi 6378249 145 0 00680351 128285 Arc 1950 Swaziland 6378249 145 0 00680351 128285 Arc 1950 Zaire 6378249 145 0 00680351 128285 Arc 1950 Zambia 6378249 145 0 00680351 128285 Arc 1950 Zimbabwe 6378249 145 0 00680351 128285 Arc 1960 Mean 6378249 145 0 00680351 128285 Arc 1960 Kenya A 70 6378249 145 0 00680351 128285 Arc 1960 Tanzania Lassen SK8 Embedded GPS Module Table A 85 Datums Continued A axis Trimble Standard Interface Protocol Eccentricity Description 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
10. Midway Astro 1961 6378249 145 0 00680351 128285 Minna 6378249 145 0 00680351 128285 Nahrwan Masirah 6378249 145 0 00680351 128285 Nahrwan UAE 6378249 145 0 00680351 128285 Nahrwan Saudia 6377483 865 0 00667437223180 Namibia 6378388 000 0 00672267002233 Naparima 6378206 400 0 00676865799761 NAD 27 Western US 6378206 400 0 00676865799761 NAD 27 Eastern US 6378206 400 0 00676865799761 NAD 27 Alaska 6378206 400 0 00676865799761 NAD 27 Bahamas 6378206 4 0 00676865799761 NAD 27 Salvador 6378206 4 0 00676865799761 NAD 27 Canada 6378206 4 0 00676865799761 NAD 27 Alberta BC 6378206 4 0 00676865799761 NAD 27 East Canada 6378206 4 0 00676865799761 NAD 27 Manitoba Ont 6378206 4 0 00676865799761 NAD 27 NW Ter Sask 6378206 4 0 00676865799761 NAD 27 Yukon A 72 6378206 4 0 00676865799761 Lassen SK8 Embedded GPS Module NAD 27 Canal Zone Table A 85 Datums Continued A axis Trimble Standard Interface Protocol Eccentricity Description 6378206 4 0 00676865799761 NAD 27 Caribbean 6378206 4 0 00676865799761 NAD 27 Central Amer 6378206 4 0 00676865799761 NAD 27 Cuba 6378206 4 0 00676865799761 NAD 2
11. Figure 2 1 Motherboard Connection Points Lassen SK8 Embedded GPS Module 2 1 Hardware Integration Ww Caution Before disassembling the interface unit disconnect the unit from any external power source and confirm that both you and your work surface are properly grounded for ESD protection The interface unit motherboard contains a 3 6V lithium battery Exercise caution when removing it from the Lassen SK8 unit Remove the four screws which secure the bottom plate to the base of the metal enclosure Set the bottom plate aside Remove the two screws securing the Lassen SK8 module to the standoffs on the motherboard These screws are located at opposite ends of the receiver module see Figure 2 2 Connecbor 10Fin poniy pires used Figure 2 2 Removing the Receiver Module 3 Carefully pull the module straight off the motherboard to disengage the 8 pin header from the 10 pin socket on the motherboard see Figure 2 2 Do not rotate or flex the module while disengaging the header since this could damage the connector or the board components Pull straight up keeping the Lassen SK8 parallel to the motherboard Disconnect the RF cable connecting the Lassen SK8 module to the SMB connector on the enclosure This connection was made by pushing the antenna cable connector onto the SMB connector on the receiver To remove the antenna cable grasp the cable connector and pull it straig
12. Report Packet 0x58 lonosphere Data Type Meaning ICD 200 Sec not used SINGLE Sec 20 3 3 5 1 9 SINGLE Sec 20 3 3 5 1 9 SINGLE Sec 20 3 3 5 1 9 SINGLE Sec 20 3 3 5 1 9 SINGLE Sec 20 3 3 5 1 9 SINGLE Sec 20 3 3 5 1 9 SINGLE Sec 20 3 3 5 1 9 Table A 45 SINGLE Sec 20 3 3 5 1 9 Report Packet 0x58 UTC Data Type Meaning ICD 200 Sec not used A0 DOUBLE Sec 20 3 3 5 1 8 A 1 SINGLE Sec 20 3 3 5 1 8 delta t LS INTEGER Sec 20 3 3 5 1 8 t ot SINGLE Sec 20 3 3 5 1 8 WN t INTEGER Sec 20 3 3 5 1 8 WN LSF INTEGER Sec 20 3 3 5 1 8 DN INTEGER Sec 20 3 3 5 1 8 Table A 46 delta t LSF INTEGER Sec 20 3 3 5 1 8 Report Packet 0x58 Ephemeris Data Item Type Meaning ICD 200 Sec sv number BYTE SV PRN number t ephem SINGLE time of collection weeknum INTEGER Sec 20 3 3 3 Table 20 1 codeL2 BYTE Sec 20 3 3 3 Table 20 1 L2Pdata BYTE Sec 20 3 3 3 Table 20 1 SVacc raw BYTE Sec 20 3 3 3 Table 20 1 SV health BYTE Sec 20 3 3 3 Table 20 1 IODC INTEGER Sec 20 3 3 3 Table 20 T_GD SINGLE Sec 20 3 3 3 Table 20 A 42 t_oc SINGLE Sec 20 3 3 3 Table 20 1 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol Table A 46
13. A 17 27 Report Packet 0x47 This packet provides received signal levels for all satellites currently being tracked or on which tracking is being attempted 1 above the elevation mask and healthy according to A 32 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol the almanac The receiver sends this packet only in response to Packet 0x27 The data format is shown below Table A 32 Report Packet 0x47 Data Formats Byte Item Type 0 Count BYTE 1 Satellite number 1 BYTE 2 5 Signal level 1 SINGLE 6 Satellite number 2 BYTE 7 10 Signal level 2 SINGLE etc etc etc Up to 8 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 Units either AMU or dBHz are controlled by Packet 0x35 A 17 28 Report Packet 0x48 This packet provides the most recent 22 byte ASCII message broadcast in the GPS satellite navigation message The receiver sends this packet in response to Packet 0x28 The message effectively is a bulletin board from the Air Force to GPS users The format is free form ASCII and is often
14. BBBBBB Vertical Velocity 4 MPH CCCC Source 1 n a D 0 2D GPS 1 3D GPS 2 2D DGPS 3 3D DGPS 6 DR 8 Degraded DR 9 Unknown Age of Data Indicator 1 n a E 2 Fresh 10 seconds 1 Old gt 10 seconds 0 Not available Total 17 Altitude is above mean sea level in WGS 84 The GPS time of day is the time of fix rounded to the nearest second This message contains data obtained from the last 3 dimensional fix and may not be current Note The data this message is to be considered invalid and should not be used if the Age of Data Indicator is equal to 0 signifying data not available C 7 AM Alarm Lassen SK8 does not support this TAIP message C 8 Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP C 8 AP Auxiliary Port Characteristic Data String Format Table C 7 Auxiliary Port Characteristics Data String Descriptions Item of Char UNITS Format Value Baud Rate 4 n a AAAA 9600 4800 2400 1200 or 0300 of data bits 1 n a B 70r8 of stop bits 1 n a C 10r2 Parity 1 n a D N None O Odd E Even Auxiliary Port 1 n a E 1 Number Reserved 1 n a F 0 Total 9 including commas This message defines the characteristics for the auxiliary port The auxiliary port must be the RTCM input port on differential ready sensors The default settings of the auxiliary port are 4
15. Prime Power 5 volts DC 5 150 ma 75 watts typical without antenna Prime Power 5 volts DC 5 175 ma 875 watts typical with antenna P N 28367 00 RAM Backup optional 3 2 5 25 volts DC input via 8 pin header J3 1 micro amp F 4 Input Output F 4 1 Interface Two TTL level bi directional serial I O ports on J3 8 pin header F 4 2 Protocols Available Trimble Standard Interface Protocol TSIP binary data I O provides maximum bi directional control over all GPS board functions Sample C source code interface routines are available NMEA 0183 Industry standard ASCII protocol for marine electronics applications Supports NMEA sentences GGA VTG GLL ZDA and GSV GSS RMC Note GGA are factory default messages Lassen SK8 Embedded GPS Module F 3 Specifications and Mechanical Drawings F 5 Pulse Per Second F 5 1 Timing Rising edge of pulse synchronized to UTC within 100 ns nominal F 5 2 Pulse Width 10 microsecond wide pulse rising edge is 20 nanoseconds or less depending upon distributed capacitance in cable F 5 3 Output TTL level signal F 6 RF Interference F 6 1 Jamming Resistant to broadband noise jamming where jamming to signal power ratio is 20 dB or less measured at the antenna preamplifier interface when input signal is at 160 dBW F 6 2 Burnout e Protected from damage by RF signals at frequencies 100 MHz or more from the L1 freq
16. Lassen SK8 Mechanical Drawing Bullet F 10 Lassen SK8 Embedded GPS Module xiii Xiv Lassen SK8 Embedded GPS Module List of Tables Table 1 1 Table 1 2 Table 1 3 Table 2 1 Table 2 2 Table 3 1 Table 3 2 Table 4 1 Table 4 2 Table A 1 Table A 2 Table A 3 Table A 4 Table A 5 Table A 6 Table A 7 Table A 8 Table A 9 Table A 10 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 Lassen SK8 Embedded GPS Module Lassen SK8 Starter Kit 22e 1 4 Lassen SK8 e ee 1 4 Lassen SK 8 Optional 1 4 Connector Signals ee 2 3 Power Requirements 2 4 soU el CR Puma uum de a GS 2 4 Default Serial Port Characteristics a 3 2 TSIP Message 3 6 Default Satellite Mask 4 3 Lassen SK8 Operating Limits 4 9 Automatic Output Packets ne A 2 Customizing Receiver Operation A 4 Automatic Position and Velocity Reports Control Setting Bits A 5 Warm Start Packet Commands 2e A 6 Packet Power up Output Messages ee A 7 Differential GPS Packet TSIP Control Commands A 7 Timing Packet TSIP
17. Note 3 Not all Packet 0x39 operations have a response See Packet 0x39 description Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 14 Report Packets Sent by the GPS Receiver to the User The table below summarizes the packets output by the receiver The table 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 23 Table A 13 User Selected Report Packet Options Output ID Packet Description Input ID 0x41 GPS time 0x21 auto 0x42 single precision XYZ position 0x25 0x37 auto 0x43 velocity fix XYZ ECEF 0x37 auto 0x45 software version information Ox1F power up 0x46 health of Receiver 0x26 auto power up 0x47 signal level for all satellites 0x27 0x48 GPS system message 0x28 0x4A single precision LLA position 0x37 auto 0x4B machine code status 0x26 auto power up 0x4D oscillator offset 0x2D Ox4E response to set GPS time Ox2bE 0x55 I O options 0x35 Ox6E Synchronized Measurement packet output control Ox6F Synchronized Measurement packet Auto 0x56 velocity fix ENU 0x37 auto 0x57 information about last computed fix 0x37 0x58 GPS system data acknowledge 0x38 0x59 sat enable disable amp health heed 0x39 0x5A raw measurement data Ox3A 0
18. The Lassen SK8 is an excellent source for accurate system timing Examples of applications requiring accurate time are environmental data acquisition or synchronization of communications networks The timing functions of the receiver are supported by the TSIP protocol See Report Packet 41 in Appendix A for a description of the time function reports for TSIP Note Note that GPS time differs from UTC Universal Coordinated Time by a variable integer number of seconds UTC z GPS time GPS UTC Offset As of July 1997 the GPS UTC offset was 12 seconds The offset increases by 1 second approximately every 18 months System designers should plan to read the offset value as a part of the timing interface to obtain UTC The GPS week number is in reference to a base week Week 0 starting January 6 1980 The current GPUSTC offset is contained within the almanac transmitted by the GPS system The Lassen SK8 must have a complete almanac before the offset data is valid Effect of GPS Week Number Roll over WNRO At 0000 hours Greenwich Mean Time GMT on 21 22 August 1999 the GPS Week Number will roll over from 1023 to zero Trimble receivers have numerous built in protections to prevent this from being a catastrophic event Systems may benefit however from extra care with the first power up after WNRO Note GPS Week Numbers occupy a range from zero to 1023 such that the Week Number Roll Over WNRO occurs every 1024 weeks or approxima
19. West altitude 10 meters gt SIP 37 122 0001 lt Lassen SK8 Embedded GPS Module C 15 Trimble ASCII Interface Protocol TAIP C 14 LN Long Navigation Message Data String Format AAAAABBBCCCDDDDDDDEEEEFFFFFFFGGGGGGGHHIIIJK KKKLMMMNOOPPOQOPPOO PPOORRRRRRRRRRST Table C 14 Long Navigation Message Data String Descriptions Item of Char UNITS Format Value GPS Time of day 8 Sec AAAAA BBB Latitude 10 Deg CCC DDDDDDD Longitude 11 Deg EEEE FFFFFFF Altitude above MSL 9 Ft GGGGGGG HH Horizontal Speed 4 MPH ILJ Vertical Speed 5 MPH KKKK L Heading 4 Deg MMM N Number of SVs used 2 n a OO SV Id See note 2 n a PP IODE See note 2 n a QQ Reserved 10 n a RRRRRRRRRR Source 1 n a S 0 2 2D GPS 1 3D GPS 2 2D DGPS 3 3D DGPS 6 DR 8 Degraded DR 9 Unknown Age of Data Indicator 1 n a T 2 Fresh lt 10 sec 1 Old gt 10 sec 0 Not available Total 65 Plus the number of SV s used times 4 DX Note At least 2 satellites are required to get the LN Message Position is in latitude positive north and longitude positive east WGS 84 Heading is in degrees from True North increasing eastwardly The GPS time of day is the time of fix rounded to the nearest second DX Note The data in this message is to be considered invalid and should not be used if the Age of Data Indicator is equal to 0 signifying data no
20. health on all 32 satellites Satellite 0 all 32 satellites any one satellite PRN number This information is not held in battery backed memory At power on and after a reset the default values are set for all satellites Ww Caution Ignoring satellite health flags can cause the GPS receiver software to lock up An unhealthy satellite may contain defective data Use extreme caution when ignoring satellite health flags A 17 21 Command Packet 0x3C This packet requests the current satellite tracking status The GPS receiver returns Packet OxSC if data is available Table A 24 Command Packet 0x3C Data Format Item Meaning Satellite All satellites in the current tracking set Desired satellite A 28 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 17 22 Report Packet 0x41 This packet provides the current GPS time of week and the week number The GPS receiver sends this packet in response to Packet 0x21 and during an update cycle Update cycles occur approximately every 5 seconds The data format is shown below Table A 25 Report Packet 0x41 Data Formats Item Type Units GPS time of week SINGLE seconds Extended GPS week number INTEGER weeks GPS UTC offset SINGLE seconds Note UTC time lags behind GPS time by integer number of seconds UTC GPS time GPS UTC offset Ww Caution GPS week numbers run from 0 to 1023 and then cycles ba
21. query DGPS corrections 0x65 0x85 query DGPS operating mode amp status 0x62 0x82 load DGPS Type 1 correction 0x60 load DGPS Type 2 correction 0x61 Lassen SK8 Embedded GPS Module A 11 Trimble Standard Interface Protocol Table A 11 Recommended TSIP Packet Data Continued Function Description GPS system query load GPS system data GPS system message Initialization full reset clear battery backup and or non volatile settings soft reset set GPS time set exact LLA set approx XYZ set approx LLA set exact XYZ A 12 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 13 Command Packets Sent to the Receiver The table below summarizes the command packets sent to the receiver The table includes the input Packet ID a short description of each packet and the associated response packet In some cases the response packets depend on user selected options These selections are covered in the packet descriptions beginning on page A 13 Table A 12 User Selected Command Packet Options Input ID Packet Description Output ID Ox1E clear battery back up reset See Note 1 Ox1F software version 0x45 0x21 current time 0x41 0x23 initial position XYZ ECEF 0 24 request receiver position fix mode 0 6 0 25 soft reset amp se
22. 0 00672267002233 Geodetic Datum 1949 6378206 400 0 00676865799761 Guam 1963 6378388 000 0 00672267002233 GUX 1 Astro Lassen SK8 Embedded GPS Module 6378388 000 0 00672267002233 Hjorsey 1955 A 71 Trimble Standard Interface Protocol Table A 85 Datums Continued A axis Eccentricity Description 6378388 000 0 00672267002233 Hong Kong 1963 6377276 345 0 00663784663020 Indian Thai Viet 6377301 243 0 00663784663020 Indian India Nepal 6377340 189 0 00667053999999 Ireland 1965 6378388 000 0 00672267002233 ISTS O73 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 00680351 128285 Liberia 1964 6378206 400 0 00676865799761 Luzon Phillippines 6378206 400 0 00676865799761 Luzon Mindanao 6378249 145 0 00680351 128285 Mahe 1971 6378388 000 0 00672267002233 Marco Astro 6377397 155 0 00667437223180 Massawa 6378249 145 0 00680351 128285 Merchich 6378388 000 0 00672267002233
23. 20 velocity choose packet with I O options 1 second 0x46 health of receiver 5 seconds 0x4B machinecode status includes antenna 5 seconds fault detect 0 6 all in view satellite selection 1 second 0x82 DGPS position fix mode only in DGPS 1 second mode Note See page A 16 for a detailed description of the key receiver setup parameters A 2 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 3 Customizing Receiver Operations 3 1 3 2 A 3 3 IW To customize the Lassen SK8 receiver output for your application 1 Set up the receiver using TSIP commands until the receiver operation is as desired 2 Use command Ox8E 26 to store the settings in non volatile memory These settings will control receiver operation whenever the receiver is cold started or when battery back up is lost Table A 2 shows all of the commands that can be stored in SEEPROM TAIP Customizing To customize the receiver for TAIP on either Port 1 or Port 2 use command Ox8E 40 which sets the TAIP default settings Then use command OxBC to change port baud settings and set the language to TAIP If Port 1 is used TSIP communication will stop so use TAIP command RT specifically gt SRTSAVE_CONFIG lt to store to non volatile memory instead of Ox8E 26 settings NMEA Customizing To customize the NMEA output on Port 2 use the command 0x7A Reconfiguring to Factor
24. A method of sending digital data in which the bits come at fixed rather than random times and are synchronized to a clock Trimble ASCII Interface Protocol Designed originally for vehicle tracking applications TAIP uses printable uppercase ASCII characters in 16 message types for easy integration with mobile data modems terminals and personal computers The TAIP protocol is defined in full in Appendix C Trimble Advanced Navigation Sensor Also refers to a Trimble specified interface protocol for digital packet communication to from the GPS receiver Data output includes time tagged position and velocity satellite status dilution of precision factors and diagnostics of GPS receiver operational status Also see TSIP Trimble Navigation Ltd Reference Locator 4000RL Product name for the Differential GPS Reference Station Lassen SK8 Embedded GPS Module Glossary 2 D Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed TSIP 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 URA Satellite user range accuracy The URA is sent by the satellite and is computed by the GPS operators It is a statistical indicatory of the contribution
25. Bogota Observatory 6378388 000 0 00672267002233 Compo Inchauspe 6378388 000 0 00672267002233 Canton Island 1966 6378249 145 0 00680351 128285 Cape 6378206 400 0 00676865799761 Cape Canaveral mean 6378249 145 0 00680351 128285 Carthage 6378388 000 0 00672267002233 Chatham 1971 6378388 000 0 00672267002233 Chua 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 lre 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
26. C 22 Error Codes Nibble 1 Definition Antenna Feedline fault Excessive Open or Short See reference Value of B note frequency error Notes 0 No problems Reported 1 X 2 X 3 X X Table C 23 Error codes Nibble 2 Definition Alignment Signal Alignment Error Battery back processor Error Channel Channel or up Failed See Error See or Chip 1 See Chip 2 See Value of C note note note note 0 No problems reported 1 X 2 X 3 X X 4 X 5 X X 6 X X T X X X 8 X 9 X X A X X B X X X C X X D X X X E X X X F X X X X Lassen SK8 Embedded GPS Module C 23 Trimble ASCII Interface Protocol TAIP Table C 24 Error Codes Nibble 4 Definition Battery Stored Powered Almanac is Synthesizer Timer Clock A to D not Complete Value of F Fault Fault Converter Fault or Current 0 No problems reported 1 X 2 X 3 X X 4 X 5 X X 6 X X 7 X X X 8 X 9 X X A X X B X X X C X X D X X X E X X X F X X X X DX Note After this error is detected its bit remains set until the sensor is reset Note This bit is 1 if the last computed reference frequency error indicated that the reference oscillator is out of tolerance C 24 Lassen SK8 Embedded GPS Module TM Time Date Data String Format Trimble ASCII Interface Prot
27. DC and DD TAIP messages described herein apply only to differential ready sensors and are provided to enclose differential corrections within the TAIP format Use of DC and DD messages to input corrections requires only one communications channel Use of the auxiliary port to input RTCM 104 corrections assumes a separate communications channel is available for broadcast and receipt of differential corrections Note The TAIP software toolkit GPSSK does not support DC and DD messages Lassen SK8 Embedded GPS Module C 13 Trimble ASCII Interface Protocol TAIP C 12 C 14 ID Identification Number Data String Format AAAA Table C 12 Identification Number Data String Descriptions Item of Char UNITS Format Vehicle ID 4 n a AAAA Total 4 This message is used to report or set the vehicle s or sensor s unique four character alpha numeric user assigned ID The default at cold start is 0000 Example The following message will set the vehicle ID to 101 gt 5100101 lt The following is simply a response a query for vehicle ID gt RIDO101 lt Note The sensor will always check incoming messages for ID and compare with the vehicle ID set in the sensor s memory If no ID is included in the message the sensor will assume a match and accept the message If the message sent to the sensor does contain a vehicle ID but that ID does not match the ID previously set in the sensor the
28. E 2 The Lassen SK8 outputs two messages GGA NMEA Version 2 1 and VTG These messages are output at a 1 second interval with the GP talker ID and checksums Note The user can configure a custom mix of the messages listed in table C 2 See TSIP command packet BB in Appendix A for details on configuring NMEA output Lassen SK8 Embedded GPS Module NMEA 0183 Table E 2 Lassen SK8 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 The format for each message in table C 2 is described in more detail in the next section E 4 NMEA 0183 Message Formats E 4 1 GGA GPS Fix Data The GGA message includes time position and fix related data for the GPS receiver Table E 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
29. Each second represents approximately 100 76 ft 30 7 m Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP C 5 Message Data Strings The following table lists all the TAIP messages currently defined and comments regarding their application Table C 5 Message Data String Descriptions Identifier Message Name AL Altitude Vertical Velocity AP Auxiliary Port Characteristic Compact Position Solution DC Differential Corrections DD Delta Differential Corrections ID Vehicle ID IP Initial Position LN Long Navigation Message PR Protocol PT Port Characteristic PV Position Velocity Solution RM Reporting Mode RT Reset ST Status Time Date VR Version Number The data string format of each message is described in the following pages Note The Trimble GPS sensor may not support all the message types Please refer to page 1 of this appendix for a list of the messages your sensor supports Note All TAIP message characters must be uppercase Lassen SK8 Embedded GPS Module C 7 Trimble ASCII Interface Protocol TAIP C 6 AL Altitude Up Velocity Data String Format AAAAABBBB UJ BCCCCDE Table C 6 Altitude Up Velocity Data String Descriptions Item of Char UNITS Format Value GPS Time of day 5 Sec AAAAA Altitude 6 Meter
30. Figures Figure 1 1 Figure 1 2 Figure 1 3 Figure 1 4 Figure 1 5 Figure 1 6 Figure 1 7 Figure 1 8 Figure 1 9 Figure 1 10 Figure 1 11 Figure 2 1 Figure 2 2 Figure 2 3 Figure 4 1 Figure F 1 Figure F 2 Figure F 3 Figure F 4 Figure F 5 The Module Installed Inside the Interface Unit 1 5 Receiver Modules 26 3 40k a moe ae ol BO RD a id 1 6 Starter Kit Interface Unit 22e 1 7 Open Collector PPS eee Bae eee ES ee RUE 1 7 Magnetic Mount GPS 1 8 Hard Mount GPS 1 8 Bullet II GPS Antenna 2 ee ee 1 9 DC PowerCable 2 c9 x Eo 9 exi rex edes 1 9 AC DC Power 1 10 Interconnect Diagram 1 11 TSIPCHAT Command Window and Report Window 1 12 Motherboard Connection 2 1 Removing the Receiver 2 2 Interface Connector Pin 1 2 3 Lassen SK8 Block Diagram 4 12 Lassen SK8 Mechanical Drawing Circuit Board and Shield F 6 Lassen SK8 Mechanical Drawing Motherboard Schematic F 7 Lassen SK8 Mechanical Drawing Miniature Antenna F 8 Lassen SK8 Mechanical Drawing Trimble Bulkhead Antenna F 9
31. INTEGER degrees Satellite azimuth 52 53 27 54 SNR BYTE AMUs 4 Number of AMUs times four A 52 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol Table A 57 Synchronized Measurements Report Continued Meaning 28 35 Pseudorange DOUBLE meters Full L1 C A 55 62 Pseudorange filtered 36 43 Carrier Phase DOUBLE cycles L1 band Continuous 63 70 Phase truncated to integer value 44 47 Doppler SINGLE L1 band Doppler 71 74 End of the packet data 21427n Checksum INTEGER Sum of bytes before 22427n checksum starting with preamble 23427n Postamble Note The sign convention provides for a carrier phase decrease when the pseudorange increases and the doppler is negative Table A 58 FLAGS1 Bit Assignments Meaning Reserved set to zero L1 Carrier phase Cycle Slip 0 No 1 Yes Reserved set to zero Reserved set to zero Valid L1 Carrier phase 0 No 1 Yes Reserved set to zero Reserved set to zero New Position Calculated 0 No 1 Yes Lassen SK8 Embedded GPS Module A 53 Trimble Standard Interface Protocol A 17 50 Command Packet 0x70 Trimble OEM receivers have a number of filters Command 0x70 provides control for these filters It returns Report 0x70 There are three filters associated with 0x70 Position Velocity PV Filter Static Filter Altitude
32. Note DC and DD TAIP messages are used to enclose differential corrections within the TAIP format Note DC and DD messages used to input corrections require only one communications channel When the auxiliary port is used to input RTCM 104 corrections it assumes a separate communications channel is available for broadcast and receipt of differential corrections Note The TAIP Software Toolkit does not support DC and DD messages Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP C 11 DD Delta Differential Corrections This message provides the sensor with delta differential corrections from RTCM 104 record type 2 The values are numerical values written out in hex format thus for each byte of data there is a two digit hex number The format of the data string is as follows AAAABB CCDDDD Table C 11 Delta Differential Corrections Data String Descriptions Item of Char Type UNITS Format Modified Z count 4 WORD 6 sec AAAA Number of SVs 2 BYTE n a BB The next 3 bytes 6 characters are repeated for each SV SV PRN 2 BYTE n a CC Delta Range 4 WORD RTCM 104 DDDD Correction Note The units and scale factors are as defined by RTCM 104 version 1 The health UDRE scale factor given for the specific SV in the most recent message DC is used Delta range corrections are scaled by 0 02 meters times 2 raised to the health power The
33. ROM This socketed board may be used to evaluate future releases of firmware The standard OEM module is not equipped with a socket Lassen SK8 Embedded GPS Module Starter Kit The interface motherboard includes a 9 to 32 VDC switching power supply which provides a regulated 5 VDC to the receiver It also converts the TTL level I O to RS 232 for a direct interface to a computer The motherboard provides an open collector interface for the PPS and also includes a 3 6V lithium backup battery enabling lightening fast hot starts The Starter Kit includes an AC DC converter for powering the module from an AC wall socket The metal enclosure see Figure 1 3 provides 2 interface port connectors an antenna connector and a power connector The mounting plate is secured to the metal enclosure with four screws The eight pin header plugs into the corresponding 8 pin socket on the motherboard as shown in Figure 1 3 Figure 1 3 Starter Kit Interface Unit DX Note Due to the open collector interface the polarity of the PPS signal is inverted The pulse is a 10us negative going pulse with the falling edge synchronized to UTC When removed from the motherboard the receiver provides a TTL level positive going pulse In order to pull up the 1pps use a 10k pull up resister as shown in the following illustration 5Vdc 10K ohm PORT 1 PPS Pin 9 Pin 9 Figure 1 4 Open Collector PPS The Starter Kit interface unit provides fifty pe
34. S serial port baud rate C 9 C 18 data bits C 9 parity C 9 C 18 stop bits C 9 C 18 serial port characteristics 3 2 signal processor 4 11 starter kit 1 3 status codes C 22 Synchronized Measurements Report A 52 T TAC xx TAIP data string format C 7 message format C 2 qualifier query C 27 response C 27 scheduled reporting C 27 set C 28 vehicle ID C 14 reporting frequency C 27 reporting mode checksum flag C 20 scheduled reporting flag C 20 vehicle ID flag C 20 sample communications C 28 tool kit see GPSSK D 1 TAIP message Messageidentifier C 7 Technical Assistance xx tips xxii Index 2 tool kit B 1 TAIP see GPSSK D 1 trademarks iii Trimble Public FTP site xxi Trimble Standard Interface Protocol TSIP 1 3 Trimble Technical Assistance Center TAC xx TSIP 1 3 report packets A 15 tool kit B 1 TSIPCHAT B 1 V vertical velocity C 8 W warnings xxii Worldwide Web xxi Lassen SK8 Embedded GPS Module Reader Comment Form Lassen SK8 Embedded GPS Module System Designer Reference Manual P N 34149 01 We appreciate your comments and suggestions for improving this publication Contributors of particularly helpful evaluations will receive a thank you gift 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 w
35. Table A 55 Table A 56 Table A 57 Table A 58 Table A 59 Table A 60 Table A 61 xvi Command Packet 0x39 Data Formats A 28 Command Packet 0x3C Data Format A 28 Report Packet 0x41 Data Formats A 29 Packets 0x41 and 0x46 Status Code Relationships A 29 Report Packet 0x42 Data Formats A 30 Report Packet 0x43 Data Formats A 30 Report Packet 0x45 Data Formats 0 00000004 A 31 Report Packet 0x46 Data Formats A 32 Report Packet 0x46 Bit Positions and Descriptions A 32 Report Packet 0x47 Data A 33 Report Packet Ox4A Data Formats 0 000000000004 A 34 Reference Altitude 2123 Seek BE BL ee Se A 35 Report Packet Ox4B Data A 35 Report Packet 0x4B Bit Positions and Descriptions A 35 Report Packet Ox4E Data A 36 Command Packets 0x55 and 0x35 Data Descriptions A 37 Report Packet 0x56 Data Formats A 39 Report Packet 0x57 Data A 39 Report Packet 0x58 Data A 40 Report Packet 0x58 41 Report Packet 0x58 Almanac Health Data
36. Trimble Standard Interface Protocol A 12 Recommended TSIP Packets Table A 11 Function Recommended TSIP Packet Data Description Input Output Protocol and port setup set query port configuration OxBC OxBC set query NMEA configuration Ox7A 0x7B set query I O options autoreport and format options 0x35 0x55 Packet output control Ox6E 01 Ox6E 01 Navigation GPS time 0x21 0x41 position amp velocity superpacket Ox8E 20 or 0x37 auto Ox8F 20 double precision LLA 0x37 auto 0x84 double precision XYZ 0x37 auto 0x83 ENU velocity 0x37 auto 0x56 XYZ velocity 0x37 auto 0x43 Satellite and tracking information query receiver state health 0x26 0x46 0x4B query current satellite selection 0x24 0 6 query signal levels 0x27 0x47 query satellite information azimuth elevation etc 0x3C 0 5 Synchronized Measurement packet Ox6F Receiver settings query software version Ox1F 0x45 set query datum values Ox8E 15 Ox8F 15 query receiver ID amp error status 0x26 Ox4B 0x46 set query satellite flags 0x39 0x59 set query receiver configuration OxBB 0xBB set altitude for 2D mode 2 Ox4A disable PV altitude filters 0x70 0x70 set query positioning mode 2D v 3D OxBB 0xBB
37. all receiver and satellite clock frequency errors It is expressed in Hertz at the L1 carrier 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 Lassen SK8 Embedded GPS Module A 45 Trimble Standard Interface Protocol The receiver codephase resolution is 1 16th of a C A code chip this corresponds to 1 16 C A code chip 977 517ns 16 61 0948 ns 61 0948 speed of light m s 18 3158 meter 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 speed of light 1 ms speed of light m s 300km approx 299 792458 km precise The satellite time of transmission for a measurement be reconstructed using the code phase the time of measurement and the user determined integer number of milliseconds DX Note The receiver occasionally adjusts its clock to maintain time accuracy within 1 msec At this time all pseudorange values for all satellites are adjusted upward or downward by one millisecond Message Ox6F shows this clearly it is hidden in Ox5A A 46 Lassen SK8 Embedded GPS
38. 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 method of sending data in which the bits can be sent at random times Data transmission is not synchronized to a clock With asynchronous transmission each character is transmitted one at a time with a start bit at the beginning and one or more stop bits at the end Any amount of time can elapse before the next character is sent V 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 Lassen SK8 Embedded GPS Module Glossary 1 Glossary 2 D bandwidth baud bit bit rate byte C A code carrier channel chip chip rate configuration data bits datum DCE default setting DGPS Glossary 2 Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed 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 dat
39. current position mode and communication port setup information is lost by the execution of this command In normal use this packet should not be sent It is very helpful to keep a fresh copy of the current almanac which is stored in the file GPSALM DAT collected by the TSIPCHAT command This allows near instantaneous recuperation by the receiver in case of power loss or clearing of battery backed memory by using the TSIPCHAT command to load it back into the receiver memory Table A 15 Command Packet 0x1E Format Value Meaning 0x46 Erase BBRAM reset ASCII F nonvolatile memory to factory default and restart 0x4B Erase BBRAM and Reset Command Packet 0x1F This packet requests information about the version of software running in the Navigation and Signal Processors This packet contains no data The GPS receiver returns Packet 0x45 Command Packet 0x21 This packet requests current GPS time This packet contains no data The GPS receiver returns Packet 0x41 Lassen SK8 Embedded GPS Module A 17 5 A 17 6 A 17 7 A 17 8 A 17 9 Trimble Standard Interface Protocol Command Packet 0x23 This packet provides the GPS receiver with an approximate initial position in XYZ coordinates This packet is useful if the user has moved more than a 1 000 miles after the previous fix Note that the GPS receiver can initialize itself without any data from the user this packet merely reduc
40. earth s center the z axis through the North Pole and the x axis through longitude 0 degrees latitude 0 degrees Velocity is reported relative to the same axes UTM Universal Transverse Mercator UTM is a mapping coordinate system used by many government agencies There are also two time coordinate systems GPS time GPS time is determined by an ensemble of atomic clocks operated by the Department of Defense DOD UTC time UTC time is the world standard maintained by an ensemble of atomic clocks operated by government organizations around the world GPS time is steered relative to Universal Coordinated Time UTC GPS does not recognize leap seconds resulting in a situation where GPS time is currently 12 seconds ahead of UTC time Time tags for most output messages can be in either UTC time or GPS time as chosen by TSIP command 0x35 Lassen SK8 Embedded GPS Module Operation and Performance 4 7 2 4 7 3 NMEA 0183 The NMEA 0183 protocol only supports LLA format and UTC time Velocity is always described as horizontal speed and heading vertical speed is not output TAIP The TAIP protocol only supports LLA position output Timetags are GPS except for the TM time mark message 4 8 Performance Characteristics 4 8 1 4 8 2 4 8 3 Update Rate The Lassen SK8 computes and outputs position solutions once per second on the second NMEA outputs can be scheduled at a slower rate using TSIP command 7
41. edge is typically less than 20 nSec The falling edge should not be used The timing accuracy is 100 nanosecond 1X and is available only when valid position fixes are being reported Repeatability checks of 10 sets of 100 one second samples taken over a period of 20 minutes showed an average variation of approximately 100 nanoseconds not allowing for SA 2 6 Mounting The Lassen SK8 provides four 0 125 inch mounting holes that will accept 3 16 inch round or hex standoffs with 3 8 inch height and 4 or M3 mounting screws Space constrained environments may require a different stand off Refer to the mechanical outline drawing in Appendix F for dimensions and clearances 27 RF Shield An optional RF shield is available for production versions of the standard temperature Lassen SK8 module The production versions of the Lassen SK8 do not have a socketed EPROM This RF shield protects the GPS module from interference with other electronics and also makes the module compliant with the CE emission specification The RF shield is not compatible with the socketed board provided in the Starter Kit nor with the extended temperature board that has a TCXO oscillator Note Many installations do not require the optional shield The Lassen SK8 is designed to be immune to most interference Lassen SK8 Embedded GPS Module 2 5 Hardware Integration 2 6 Lassen SK8 Embedded GPS Module 3 Software Interface This chapter describes the Lass
42. in parentheses this index can be typed in for direct access of the choice 3 prompt for confirmation to confirm when asked type y y Any other keystroke will be negative including just the ENTER key TSerial Port Control To control the serial port settings on the data channel Channel A of the Lassen SK8 use the TSIP 0 x BB command To control the serial port settings on the computer use the keystroke CTRL I keys This keystroke does not generate a TSIP packet it prompts for the parameters for the buffered serial port On start up the program automatically sets the port parameters to 9600 baud 8 odd 1 If the port parameters are changed from the default during the execution of TSIPCHAT upon exit the program asks if the serial port is to be reset to the default File Storage TSIPCHAT provides for file storage of a native binary TSIP stream The native binary stream records the data coming off the serial port into a file To turn data collection on and off use the keystroke CTRL F The user has the option to append to a previously existing file All report packet bytes are recorded into the file whether translatable into packets or not The exception is that using ESCAPE to terminate the program exits gracefully i e not record the partially received packet at the end of the file Using the plus character does not terminate gracefully and records all bytes at the end The recorded binary data stre
43. mask Read Only Memory A communication standard for digital data Specifies a number of signal and control lines RS 232 is often associated with a 25 pin connector called a DB 25 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 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 Glossary 7 Glossary 2 D serial communication serial port signal to noise level signal to noise ratio SNR spread spectrum SPS start bit stop bit SV synchronous communication TAIP TANS TNL 4000RL Glossary
44. of Microsoft Corporation Intel is a trademark of Intel Corporation All other brand names are trademarks of their respective holders Disclaimer of Warranty EXCEPT AS INDICATED IN LIMITED WARRANTY HEREIN TRIMBLE HARDWARE SOFTWARE FIRMWARE AND DOCUMENTATION IS PROVIDED AS IS AND WITHOUT EXPRESS OR LIMITED WARRANTY OF ANY KIND BY EITHER TRIMBLE OR ANYONE WHO HAS BEEN INVOLVED IN ITS CREATION PRODUCTION OR DISTRIBUTION INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE TRIMBLE HARDWARE SOFTWARE FIRMWARE AND DOCUMENTATION IS WITH YOU SOME STATES DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES SO THE ABOVE EXCLUSION MAY NOT APPLY TO YOU Limitation of Liability IN NO EVENT WILL TRIMBLE OR ANY PERSON INVOLVED IN THE CREATION PRODUCTION OR DISTRIBUTION OF THE TRIMBLE PRODUCT BE LIABLE TO YOU ON ACCOUNT OF ANY CLAIM FOR ANY DAMAGES INCLUDING ANY LOST PROFITS LOST SAVINGS OR OTHER SPECIAL INCIDENTAL CONSEQUENTIAL OR EXEMPLARY DAMAGES INCLUDING BUT NOT LIMITED TO ANY DAMAGES ASSESSED AGAINST OR PAID BY YOU TO ANY THIRD PARTY RISING OUT OF THE USE LIABILITY TO USE QUALITY OR PERFORMANCE OF SUCH TRIMBLE PRODUCT INCLUDING HARDWARE SOFTWARE FIRMWARE AND DOCUMENTATION EVEN IF TRIMBLE OR ANY SUCH PERSON OR ENTITY HAS BEEN ADVISED OF THE POSSIBILITY OF DAMAGES OR FOR ANY CLAIM BY ANY OTHER PARTY SOME STATES DO NOT AL
45. of the number of visible satellites If the altitude is not entered the receiver uses mean sea level as the default altitude The greater the deviation between the actual and default altitudes the greater the error in the 2D position For TSIP applications enter local altitude in MSL HAE via TSIP packet 2AH see Appendix A Note 2D Manual mode is not recommended for differential GPS applications since any deviation in altitude will cause a significant error in the latitude and longitude Only use the 2D Manual mode for flat land or marine applications where the elevation is known or constant For DGPS applications the 3D Manual mode is the recommended positioning mode for the highest level of accuracy Lassen SK8 Embedded GPS Module 4 5 Operation and Performance 3D Manual In 3D Manual mode the Lassen SK8 will only generate 3 dimensional 3D position solutions latitude longitude and altitude A 3D solution requires at least four visible satellites which pass the mask criteria If less than four conforming satellites are visible the Lassen SK8 will suspend position data outputs 3D Manual mode is recommended for differential GPS applications requiring the highest level of accuracy 2D 3D Automatic The default operating mode for the Lassen SK8 is 2D 3D Automatic In this mode the Lassen SK8 attempts to generate a 3 dimensional 3D position solution if four or more satellites meeting the mask criteria are visible If only thr
46. or odd of the number of items in a set e g bits in a byte Position Dilution of Precision PDOP is a unitless figure of merit that describes how an uncertainty in pseudo range affects position solutions A value based on PDOP that defines when the GPS receiver processor should switch between 2 D and 3 D GPS modes The PDOP constellation switch is only active when the GPS mode of operation is set to Auto 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 A formal set of rules that describe a method of communication The protocol governs the format and control of inputs and outputs 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 Random Access Memory Memory in which information can be referred to in an arbitrary or random order The contents of RAM are lost when the System Unit is turned off Lassen SK8 Embedded GPS Module Glossary 2 D range range rate read only memory real time clock relative positioning rise set time ROM RS
47. position measurements Doppler shift The apparent change in frequency of a received signal due to the rate of change of the range between the transmitter and receiver earth centered earth fixed 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 elevation angle The angle between the line of sight vector and the horizontal plane Lassen SK8 Embedded GPS Module Glossary 3 Glossary 2 D elevation mask angle ellipsoid ephemeris epoch firmware frequency GDOP geodetic datum geoid Glossary 4 Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed 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 semimajor axis a and th
48. program does not support the TAIP messages DC and DD These messages are used to input differential corrections to the receiver and are defined as special TAIP format versions of RTCM SC 104 Type 1 and Type 2 messages The GPSSK program requires well over 500K RAM It may not run in a DOS window and may require removal of TSRs D 1 The GPSSK Files GPSSK is included on the on 3 5 inch DOS formatted GPS Toolkit diskette The diskette contains the following GPSSK related files GPSSK EXE The executable GPSSK program GPSSK HLP The on line context sensitive help file e READ ME Current information about GPSSK TAIP C Sample source code for encoding and decoding TAIP Lassen SK8 Embedded GPS Module D 1 GPSSK User s Guide TAIP 0 2 TAIP C Source File The sample source code for encoding and decoding TAIP messages is provided as a guide for the system integrator who is developing a communications controller that handles TAIP There is no warranty of any kind on this software Use it at your own risk The distribution diskette is not copy protected Before using GPSSK or installing on your hard disk make a working copy and put the original diskette in a safe place During normal use GPSSK will save configuration information to the diskette or current directory Storing the original diskette away will allow you to restore the original configuration should you encounter problems Copy the files GPSSK EXE and GPSSK HLP to a hard disk di
49. provides the following features in a single package Integrates an 8 channel DSP with 4 correlators per channel 32 bit microprocessor Real time clock DUART The 8 channel 32 correlator design provides extremely fast cold starts while delivering 2 meter DGPS performance The high level of integration provides a small footprint 3 25 x 1 25 x 0 40 and contributes to the lowest power consumption 75 watts for a complete GPS receiver The combination of small size and low power consumption allows Lassen SK8 to be embedded in small battery operated devices and in devices where heat dissipation must be minimized The Starter Kit makes it simple to evaluate the Lassen SK8 module s exceptional performance The kit includes the following Lassen SK8 receiver installed inside an interface unit Magnetic mount antenna AC power adapter Serial interface cable GPS Tool Kit Software used to communicate with the GPS module Lassen SK8 Embedded GPS Module 1 1 Starter Kit The interface unit is a sturdy metal enclosure containing an interface motherboard The motherboard accepts 9 32 VDC power and provides regulated 5V and 3 6V BBU power to the Lassen SK8 receiver module The motherboard also provides two RS 232 connectors for quick and direct connection to a PC COM port The Lassen SK8 board can be removed from the motherboard for integration into the user s application see Chapter 2 Hardware Integration 1 1 Lassen
50. rature n ss ewes aa buy eos A y ee d Se Ee P ee F 2 F 2 2 Vibration 4 2 uns deri RS Bem ede dee SP eoa F 2 F 2 3 Al t ude 4 9 sce eR F 2 F 2 4 Humidity avg ee esd Shave Me mE E ho te e te F 2 F 3 Physical Characteristics s cri les F 3 F 3 1 SIZe Lo xu no ues cda qr PER ARDOR OS D gt Ced ndi AP F 3 F 3 2 WiC TO ace dorem oret UG y IR dr te iS ONES qii opens daas F 3 F 3 3 unu cL F 3 E4 Input Output ssc odes Bead ho nee tg hte ele Se he n Re UR PORUM ea F 3 F 4 1 Interface ob A bene E PEERS SUDORE INED Uds F 3 F 4 2 Protocols Available r 3 FES 3pulse Per Second mendas us uot A ls BH IS ld 4 5 1 Timing ee A Qo Reo ett eU i e ota 4 5 2 od ad oeste a bal Me hs s 4 5 3 tie ga cack Ib Be ee Se eA het ier cde F 4 E 6 REIntert rence sete Ao s ELEM ols LA e IC ee o EAL F 4 F 6 1 Emir c F 4 F 6 2 Burnout uuu yox NUS Pee OR Bhs AUR A ee VS F 4 F 7 Lassen SK8 Crystal 5 F 5 F 7 1 Electricals o Ga Actes qo Gen eh Bae F 5 F 7 2 Environmental ses w ee hb ake erro oes hoe SR NT F 5 Lassen SK8 Embedded GPS Module xi xii F 7 3 Glossary Index Mechanical Lassen SK8 Embedded GPS Module List of
51. seconds interval between reports Tmax GGGG optional vehicle identification number user selected HH optional checksum lt End of message delimiter DX Note If BBBB 0 then the message output is disabled If FFFF 0 maximum time feature is disabled the unit will only report if current position is greater than or equal to the delta distance specified in EEEE Example When the message gt DPV0030000505000900 ID 0105 lt is sent to the GPS receiver it specifies that vehicle number 105 GGGG 0105 is to report the Position Velocity message AA PV whenever its current position differs from the previously reported position by at least 500 meters EEEE 0500 but no more often than every 30 seconds BBBB 0030 or less often than every 15 minutes F FFF 0900 seconds The minimum and maximum time out reports are to be issued with a 5 second offset CCCC 0005 from the top of the hour The optional checksum was not used in this example The square brackets shown in the format description above are used to indicate optional data The brackets themselves are never included in the actual TAIP message string Lassen SK8 Embedded GPS Module C 5 Trimble ASCII Interface Protocol TAIP C 4 C 6 The D message qualifier was designed by Trimble for use by Ambulance Companies to limit communication traffic between mobile units and the base when the ambulances are stationary on station When the ambulance has reached its
52. stationary dispatch site the operator signals the base by voice or by pushing a button on a Mobile Data Terminal MDT signifying that the unit is now on station Once this communication is made the base operator issues a D qualifier and message so that the ambulance will only report either when it moves off station or at specific reporting intervals Latitude and Longitude Conversion The TAIP protocol reports latitude as positive north decimal degrees and longitude as positive east decimal degrees using the WGS 84 datum For your application you may wish to convert to degrees minutes and seconds The following example illustrates the conversion of decimal degrees to degrees minutes and seconds Example Given latitude and longitude in decimal degrees Latitude 37 39438 degrees Longitude 122 03846 degrees Convert latitude by multiplying the decimal fraction of degrees by 60 to convert to minutes 0 39438 x 60 23 6628 minutes Retain the integer 23 portion as the minutes then multiply the decimal fraction by 60 to convert to seconds 0 6628 x 60 39 768 seconds Since the sign of the latitude in this example is positive the result is Latitude N 37 23 39 77 The longitude is converted in the same fashion Longitude W 122 02 18 46 Note At the earth s equator one degree of latitude and longitude represents 68 7 miles therefore 0 00001 degrees represents approximately 3 6 feet or 1 1 meters
53. to Trimble for warranty service Trimble shall pay all shipping charges for the return of products to the Customer This warranty shall not apply to defects resulting from one or more of the following Improper or inadequate maintenance by the buyer Buyer supplied software or interfacing Unauthorized modification or misuse Operation outside of the environmental specifications of the product Improper installation where applicable Lightning or other electrical discharge Fresh or salt water immersion or spray Normal wear and tear on consumable parts for example batteries No other warranty is expressed or implied Trimble Navigation Limited specifically disclaims the implied warranties of fitness for a particular purpose and merchantability Table of Contents Preface Scoperand Audience oe hela Gas A bo et x Bo aks Lassen SK8 Manual Organization eA XX Technical Assistancey2 IRA ae een memes Taur XX IMAM ELIT XX Worldwide Web 2 2 ss xxi Internet ETP Address ouo ud em ade debe RM Uk ae xxi mh et em Acne io Ist NE a dnt ut xxi Reader Comment xxi Document Conventions 2 fhe e eO OA Re dns ow Ue WP AT IU UR xxii Notes Tips Cautions and Warnings 22e xxii 1 Starter Kit KI bassen SK8 Overview c sober SR WR YU VERRE 1 2 1 1 1 Interf
54. ui 00 gu s 198 67 i 96 vl JUS JH9BH IN2NOdIAOO z 080 a P 696 8 cdi 000 0 96 71 LA ESSET 00 i i nti 91 6900 Quvo8 016 ee 1015 dol uiwgg s lt 1910 6161 NOSNHOP 33 T 100 95699 H0 100 5599 94A ANS gL 30 9 62 66 dW 1089 1 017 7 1 X310 E S30 I23NNO9 INNON 3d ONLY 801 60 51 0 9 00 1 Y 0vC 01 0 807 2091 L 154013NNOO TAVO 9NIIN 3015 901 ugzz al Be 3015 WOLIOB 062 011 8 Nid dO 000 0 a E el u S PIOCNVIS YIG 881 33 CE iussi aieo 7 TS 06512 0580 em f091 92 001 2 eee P Me 100690 ol l LM aow n vid vi VIO cll dAL Vid 8 1 S21 mm ma LI Eri EY E Bgoo uuc 10 0621 q FEE a BEG i 105 901 Y du uuo 0 100 96 1 1 UIGPO MON MHI QWOB hdd Elta NOOSA NH NO SNOISIABH vee wee COMM ee es ee ee ee ee SIME it Board Lassen SK8 Mechanical Drawing Figure F 1 Lassen SK8 Embedded GPS Module F 6 Specifications and Mechanical Drawings v v s x ecase E Am Jequny qus
55. 17 35 0 55 A 37 A 17 36 Report Packet 0x56 e ge es te we ee A 39 A l737 Report Packet OX57 2 4 ese Gye RU RAE x pec dos A 39 A 17 38 0 58 A 40 A4739 Report Packet OXI Iy Sched a RU ened dO ous te A 44 A 17 40 0 5 A 45 A 17 41 Report PacketOxSC 2e A 47 A 17 42 0 60 Type 1 Differential GPS CorrectionsA 48 17 43 0 61 Set Differential GPS CorrectionsA 49 A 17 44 0 62 A 49 A 17 45 0 65 A 50 A 17 46 0 6 A 50 A 17 47 Command Packet Ox6E Set or Request Synchronized Measurement Parameters A 51 Enable Disable Synchronized Measurements A 51 Output Level WO een redu vem ROS A 51 A 17 48 Report Packet Ox6E Synchronized Measurements A 52 A 17 49 Report Packet Ox6F 5 1 A 52 A 17 50 0 70 A 54 ALA TOL Report 0x70 of uoo docs te ie XP e deed A 54 A 17 52 0 7
56. 1969 Guyana 6378160 0 0 00669454185459 S American 1969 Paraguay 6378160 0 0 00669454185459 S American 1969 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 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 A 74 0 00667437223180 Tokyo Okinawa Lassen SK8 Embedded GPS Module Table A 85 Datums Continued A axis Trimble Standard Interface Protocol Eccentricity Description 6378388 0 0 00672267002233 Tristan Astro 1968 6378249 15 0 00680351128285 Viti Levu 1916 6378270 0 0 00672267002233 Wake Eniwetok 6378388 0 0 00672267002233 Zanderij 6377397 16 0 00667437223180 Bukit Rimpah 6378388 0 0 00672267002233 Area Astro 6377397 16 0 00667437223180 Gunung 6378388 0 0 00672267002233 Herat North 6378388 0 0 00672267002233 Hu Tzu Shan 6378388 0 0 00672267002233 Tananarive Observ 1925 6378388 0 0 006722
57. 20 old measurement flag Byte 20 value 0 flag not set gt 0 the last measurement is too old to use for a fix computation Byte 21 Integer msec flag Lassen SK8 Embedded GPS Module Byte 21 value Don t have good knowledge of integer millisecond range to this satellite 1 msec from sub frame data collection 2 verified by a bit crossing time 3 verified by a successful position fix 4 suspected msec error A 47 Trimble Standard Interface Protocol Table A 49 Report Packet 0x5C Data Formats Continued Byte Item Type Units Value Meaning Byte 22 bad data flag BYTE Byte 22 value 0 flag not set 1 bad parity 2 bad ephemeris health Byte 23 Data collection Byte 23 value flag 0 flag not set gt 0 The receiver currently is trying to collect data from this satellite A 17 42 Command Packet 0x60 Type 1 Differential GPS Corrections This packet provides the SVeeSix with differential corrections from RTCM SC 104 record types 1 and 9 in the TSIP format There is no response to this packet The units and scale factors are as defined by RTCM 104 version 1 If byte 3 bit 7 is set the unit and scale factors are defined by RTCM SC 104 version 2 If bit 6 is set the corrections are as in RTCM Type 9 records The format for this packet is shown in Table A 50 Table A 50 Report Packet 0x60 Data Formats Item Modified z count Station health not used Type 9 flag Nu
58. 2233 Prov S American 1956 S Chile 6378388 0 0 00672267002233 Prov S American 1956 Colom Lassen SK8 Embedded GPS Module 6378388 0 0 00672267002233 Prov S American 1956 Ecuador A 73 Trimble Standard Interface Protocol Table A 85 Datums Continued A axis Eccentricity Description 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
59. 232 RTCM satellite masks SA SEP Lassen SK8 Embedded GPS Module Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed A term used to refer to the distance radio signals can travel before they must be received 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 An electronic clock usually battery powered that keeps current time Used by a GPS receiver during a warm or hot start to determine where to search for GPS satellite signals 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 Refers to 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
60. 26 Note Automatic output of 5 A messages is supported in the Lassen SK8 for backwards compatibility with older TSIP applications Note See the associated superpacket output described later in this appendix Packet 8E must be used to specify which superpacket is to be output Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 17 19 Command Packet 0x38 This packet requests current satellite data almanac ephemeris etc or permits loading initialization data from an external source for example by extracting initialization data from an operating GPS receiver unit via a data logger or computer and then using that data to initialize a second GPS receiver unit The GPS receiver returns Packet 0x58 Note that the GPS receiver can initialize itself without any data from the user it merely requires more time To request data without loading data use only bytes 0 through 2 to load data use all bytes Before loading data observe the caution notice below The data formats are located in Report Packet 0 x SB Table A 22 Command Packet 0x38 Data Formats Byte Item Type Value Meaning 0 Operation Byte 1 Request data from SVeeSix 2 Load data into SVeeSix 1 Type of Byte 1 not used data 2 Almanac 3 Health page _ WN_oa 4 lonosphere 5 UTC 6 Ephemeris request only 2 Sat PRN Byte 0 data that is not satellite ID 1 32 specific satellite PRN number 3 length n Byte number
61. 3 4 5 6 7 8 9 Year number minus 1900 The first 5 bytes refer to the Navigation Processor and the second 5 bytes refer to the Signal Processor Lassen SK8 Embedded GPS Module A 31 Trimble Standard Interface Protocol A 17 26 Report Packet 0x46 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 0x26 and during an update cycle Packet Ox4B is always sent with this packet Table A 30 Report Packet 0x46 Data Formats Item Meaning Status Code Doing position fixes Don t have GPS time yet need initialization PDOP is too high No usable satellites Only 1 usable satellite Only 2 usable satellites Only 3 usable satellites The chosen satellite is unusable Status codes See Table A 31 The error codes in Byte 1 of Packet 0x46 are encoded into individual bits within the byte The bit positions and their meanings are shown below Table A 31 Report Packet 0x46 Bit Positions and Descriptions Status Code Bit Position Meaning if bit value 1 0 LSB No battery back up at start up note 1 1 not used not used not used not used not used not used 2 3 4 Antenna feed line fault open or short 5 6 7 Note After this status is detected its bit remains set until the receiver is reset
62. 5934s sob Rs dd alt ee lik hh 4 10 4 9 1 Serial Time Output 0 4 10 4 9 2 Timing Pulse Output 5 4 11 System Architecture a S be va ey eto wo d a te ee 4 11 Trimble Standard Interface Protocol Interface 5 ue Rush od tou d Ru Reges BE eR Lm Oh c Md A 1 Automatic Output Packets 2 a A 2 Customizing Receiver A 3 3 1 TAIP CustomizIBgi cuu dea 3 A 3 2 NMEA Customizing 4 4 ee ee A 3 A 3 3 Reconfiguring to Factory Default Settings A 3 Automatic Position and Velocity 5 Warm Start Packets ee 6 Packets Output A 7 Differential GPS Packets 2e A 7 Timing Packets 2 ice hake sues RR acp NO A 8 satellite Data Packets uos es Be OA ee A 8 Background Packets eA A 8 Backwards Incompatibility of Lassen SK8 Packets with Previous TSIP Versions 9 Recommended TSIP 11 Command Packets Sent to A 13 Report Packets Sent by the GPS Receiver tothe A 15 Key Setup Parameters A 16 A 15 1 Packet OxBB Set Fix Mode A 17 15 2 lt
63. 67002233 Yacare 6377397 155 0 00667437223180 Tokyo GSI coords A 20 Reference Documents Unless otherwise indicated the issue of each document which was in effect on 1 May 1987 is the issue to be used SS GPS 300B System Specification for the NAVSTAR Global Positioning System ICD GPS 200 NAVSTAR GPS Space Segment Navigation User Interfaces P N 17035 Trimble Advanced Navigation Sensor Specification and User s Manual Rev A October 1990 RTCM SC 104 RTCM Recommended Standards For Differential NAVSTAR GPS Service Version 2 0 RTCM Special Committee No 104 Published by the Radio Technical Commission For Maritime Services Washington D C January 1 1990 GPS A Guide to the Next Utility Trimble 1990 an introduction in non mathematical terms to the GPS system Lassen SK8 Embedded GPS Module A 75 Trimble Standard Interface Protocol Proceedings Institute of Navigation Washington DC A series of 3 abstracts published between 1980 amp 1986 of papers from the Journal of the Institute of Navigation Essential source material for any system designer A 76 Lassen SK8 Embedded GPS Module B User s Guide The OEM GPS Tool Kit program disk includes several TSIP interface programs designed to help developer s evaluate and integrate the GPS module and create GPS and differential GPS applications These programs run on a PC DOS platform They are intended as a base upon which to build appli
64. 7 Greenland 6378206 4 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 6378388 0 0 00672267002233 Observatorio 1966 6378200 0 0 00669342162297 Old Egyptian 1907 6378206 4 0 00676865799761 Old Hawaiian mean 6378206 4 0 00676865799761 Old Hawaiian Hawaii 6378206 4 0 00676865799761 Old Hawaiian 6378206 4 0 00676865799761 Old Hawaiian 6378206 4 0 00676865799761 Old Hawaiian 6378249 15 0 00680351 128285 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 Chilean 1963 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 0067226700
65. 8 Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed 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 160dBW This property results from modulating the L band signal with a PRN code in order to spread 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 multipath 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
66. 800 baud 8 data bits parity none and 1 stop bit Example The following command will set the auxiliary port characteristics to 2400 baud 8 data bits 1 stop bit and no parity gt SAP2400 8 1 N 1 0 lt Note See the inclusion of 0 in the reserved field Note The AP command applies only to receivers with dual serial ports Note The AP command requires commas between data fields B D X Lassen SK8 Embedded GPS Module C 9 Trimble ASCII Interface Protocol TAIP C 9 CP Compact Position Solution Data String Format AAAAABBBCCCCDDDDEEEEFG Table C 8 Compact Position Solutions Data String Descriptions Item of Char UNITS Format Value GPS Time of day 5 Sec AAAAA Latitude 7 Deg BBBCCCC Longitude 8 Deg DDDDEEEE Source 1 n a F 0 2 2D GPS 1 3D GPS 2 2D DGPS 3 3D DGPS 6 DR 8 Degraded DR 9 Unknown Age of Data Indicator 1 n a G 2 Fresh 10 sec 1 Old gt 10 sec 0 Not available Total 22 Position is in latitude positive north and longitude positive east WGS 84 The GPS time of day is the time of fix rounded to the nearest second Note The data this message is to be considered invalid and should not be used if the Age of Data Indicator is equal to 0 signifying data not available DC Differential Corrections This message provides the sensor with differential correctio
67. 83 Table A 84 Table A 85 Table A 86 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 C 10 Table C 11 Table C 12 Table C 13 Lassen SK8 Embedded GPS Module Command Packet 0x7A Data Formats for Setting NMEA Interval and Message MaskA Report Packet OX7B Message Mask Settings A 56 Report Packet 0x83 Data A 57 Report Packet 0x84 Data A 57 Report Packet 0x85 Data A 58 Report Packet 0x85 Summary Status Code Encoding A 58 Command Packet OXBB Query Mode Data Format A 59 Command and Report Packet OxBB Field Descriptions A 59 Command Packet OxBC Port Characteristics Query Field Descriptions A 60 Command Packet OxBC Field A 60 Report Packet OxBC Field A 61 Command Packet Ox8E 15 Field Descriptions A 63 Command Packet Ox8E 15 Datum Index Field Descriptions A 63 Command Packet Ox8E 15 Eccentricity of the Ellipse Parameter Field Descriptions A 63 Command Packet Ox8E 19Field Description A 64 Command Packet Ox8E 20 Field Descriptions A 64 Command Packet Ox8E 26 Definitions A 65 Report Packet Ox8F 15 Fiel
68. A 17 22 Report Packet 41 for information the Extended GPS week number Table A 20 Command Packet 0x2E Data Formats Item Type Units GPS time of week Single Seconds Extended GPS week Integer Weeks number Lassen SK8 Embedded GPS Module A 23 Trimble Standard Interface Protocol A 17 15 Command Packet 0x31 This packet is identical in content to Packet 0x23 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 A 17 16 Command Packet 0x32 This packet is identical in content to Packet 0 2 This packet provides the GPS receiver with an approximate 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 rece
69. A ALT Output 0 HAE datum 1 MSL geoid Ox4A or 0x84 Ox8F 17 Ox8F 18 ALT input 0 HAE datum 1 MSL geoid Ox2A Precision of position output 0 Send single precision packet 1 Send double precision packet 0x42 4A 8F 17 0x83 84 8F 18 position 0 output no Super Packets 1 output all enabled Super Packets Ox8F 17 Ox8F 18 Ox8F 20 not used velocity Lassen SK8 Embedded GPS Module XYZ ECEF Output 0 off 1 ENU Output 0 off 1 on not used A 25 Trimble Standard Interface Protocol Table A 21 Command Packets 0x35 and 0x55 Data Descriptions Continued Default Parameter Bit Bit Associated Byte Name Position Value Option Packet 2 timing 0 0 time type 0x42 0x43 0 GPS time 0x4A 0x83 1 UTC 0x84 0x56 Ox8F 17 Ox8F 18 1 0 reserved 2 0 reserved 3 0 reserved 4 0 reserved 5 7 0 not used 3 Auxiliary PR 0 0 off 0x5A meas 1 0 raw 0 raw Pr s in 5A Ox5A 1 filtered PR s in 5A 2 reserved 3 0 off output dBHz instead of 0x5A 0x5C 1 on AMU 0x47 Ox6F 4 7 reserved gt lt gt lt A 17 18 Command Packet 0x37 This packet requests information regarding the last position fix and is only used when the receiver is not automatically outputting positions The GPS receiver returns the position velocity auto packets specified in the 0x35 message as well as message 0x57 A
70. Ag a D 2 DANONE Help Gus Ba ret eg mh aed oe D 2 D 5 Connecting the GPS D 3 NMEA 0183 1 The NMEA 0183 Communication E 1 E 2 NMEA 0183 Message Format orr o uamo gr 020000002000 00 E 2 NMEA 0183 Message E 2 Lassen SK8 Embedded GPS Module E 4 NMEA 0183 Message E 3 E 4 1 GPS Pik Data ce Sedes A a E 3 E 4 2 GLL Geographic Position E 4 E 4 3 GSA GPS DOP and Active Satellites len E 4 E 4 4 GSV GPS Satellitesin View eee E 5 E 4 5 RMC Recommended Minimum Specific GPS Transit Data E 6 E 4 6 Track Made Good and Ground Speed E 6 E 4 7 ZDA Time amp Mods e vedo wg ete Pho E 7 F Specifications and Mechanical Drawings GPS RECEIyET Quos bos toto e ne Bk o debo Se ego So aad F 1 F 1 1 Genetal e suc Wade epe ti Je cede dir d P Re F 1 F 1 2 Sere reus Lr lue e Raven do ide s Mau di ue dem dote F 1 F 1 3 DGPS ACCURACY ose Ce eo Tn F 1 F 1 4 Datur od hU cR CR Wide ho Ie e RAD ede F 1 F 1 5 Acquisition Rate ea eA e PROB Gele ee ees F 2 F 1 6 dC F 2 F 2 Environmental Characteristics o oa a ee F 2 F 2 1 Temp
71. Ah Refer to Appendix A Dynamic Limits The dynamic operating limits for the Lassen SK8 are listed below These operating limits assume that the GPS module is correctly embedded and that the overall system is designed to operate under the same dynamic conditions Table 4 2 Lassen SK8 Operating Limits Operation Limit Acceleration 4g 39 2 m s Jerk 20 m s Speed 500 m s Altitude 18 000 m Re Acquisition Re acquisition time for a momentary signal blockages is typically under 2 seconds 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 signal is available again within 15 seconds the receiver will normally re establish track within two seconds If the lost signal is not re acquired within 15 seconds the receiver initiates a broader frequency search The receiver will continue to search for the satellite until it falls below the elevation mask Lassen SK8 Embedded GPS Module 4 9 Operation and Performance 4 9 GPS Timing 4 10 4 9 1 In many timing applications such as time frequency standards site synchronization systems and event measurement systems GPS receivers are used to discipline local oscillators The GPS constellation consists of 24 orbiting satellites Each GPS satellite contains a highly stable atomic Cesium clock which is continuously monitored and correc
72. C q N cntrl ver health opti ds down upload a V TDOP 2 14 1 15 1 81 1 21 mode is 2 auto diff diff off 8F 20 21 57 49 00 37 23 57696 122 2 19794 W 32 51 gt 0 000 E 0 000 N 0 000 U PP I 3D F 06 21 16 99h 09 BEh 05 8Bh 24 E9h 04 D8h Auto 6 SY 3 0 616 9 5 24 4 P H TDOP 2 14 1 15 1 81 1 21 mode is 2 aut ff diff off 8F 20 21 57 56 37 23 57695 122 2 19795 W 32 47 000 0 000 N 0 000 U PP I 3D F 06 21Eh 16 99h 09 BEh 05 8Bh 24 E9h 04 D8h Figure 1 11 TSIPCHAT Command Window and Report Window The upper shaded portion of the screen is the command response window and the lower portion of the screen is the automatic report window auto window The auto window displays a running account of the messages which are automatically output by the GPS module in the lower half of the screen The most common reports are the position and velocity reports Other automatic reports include receiver status and health information Lassen SK8 Embedded GPS Module Starter Kit When the GPS module has completed a position fix and starts transmitting position reports the position reports will begin scrolling in the auto window An automatic receiver health report is sent every few seconds even when no satellites are being tracked If the auto window is not displaying messages then the GPS module may not be connected properly to the computer To test the c
73. Clock Bias Rate SINGLE m s Time of Fix SINGLE seconds GPS or UTC The time of fix is in GPS or UTC time as selected by the I O timing option A 17 37 Report Packet 0x57 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 0x37 The data format is shown below Table A 40 Report Packet 0x57 Data Formats Item Type Units Byte 0 Value Velocity Source of BYTE 00 none information 01 regular fix Mfg diagnostic BYTE Time of last fix SINGLE seconds GPS time Week of last fix INTEGER weeks GPS time Lassen SK8 Embedded GPS Module A 39 Trimble Standard Interface Protocol A 17 38 Report Packet 0x58 This packet provides GPS data almanac ephemeris etc The receiver sends this packet under the following conditions On request In response to Packet 0x38 acknowledges the loading of data The data format is shown below Table A 41 Report Packet 0x58 Data Formats Item Meaning Operation Data type cannot be loaded Acknowledge Data Out Almanac Health page T oa IONO UTC Ephemeris 1 2 2 3 4 5 6 0 Sat PRN Data that is not satellite ID specific Satellite PRN number 3 length n BYTE Number of bytes of data to be loaded 4ton 3 data n BYTES The binary almanac health page and UTC data s
74. Control Commands A 8 Satellite Date Packet Data I O A 8 Background Packet Output Messages A 8 Supported Auto Output Packet Command Backward Compatibility A 9 TSIP Command Backward Incompatibility A 10 Recommended TSIP Packet Data 11 User Selected Command Packet Options A 13 User Selected Report Packet Options A 15 Setup Parameters ll llle A 16 Command Packet OXTE Format A 20 Command Packet 0x23 Data Format A 21 Packet 0x2A Set Altitude Only A 22 Reset Altitude Flag Description A 22 Command Packet 0x23 Data Format lee A 23 Command Packet 0 2 Data A 23 Command Packets 0x35 and 0x55 Data Descriptions A 25 Command Packet 0x38 Data A 27 XV 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 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
75. Differential GPS Data Time in seconds since the last Type 1 or 9 Update Differential Reference Station ID 0000 to 1023 Note The GGA message provides 3 decimal points of precision in non differential mode and 4 decimal points of accuracy differential mode Lassen SK8 Embedded GPS Module E 3 NMEA 0183 E 4 2 E 4 3 E 4 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 GLL llll lll a yyyyy yyy a hhmmss s A Table E 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 GSA GPS DOP and Active Satellites The GSA messages indicates the GPS receiver s operating mode and lists the satellites used for navigation and the DOP values of the position solution GSA a X XX XX XX XX XX XX XX XX XX XX XX XX X X X X X X Table E 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 u
76. Differential GPS corrections type 2 OxBB Differential Auto or Manual operating mode Maximum age that differential corrections will be used 0x65 Differential correction data request Lassen SK8 Embedded GPS Module A 7 Trimble Standard Interface Protocol A 8 Timing Packets If you are using the Lassen SK8 as a timing system you may need to implement the following TSIP control commands Table 7 Timing Packet TSIP Control Commands Input ID Description Output ID 0x21 get the current GPS time 0x41 0xBB setup static mode if desired 0xBB 0x38 05 request UTC parameters 0x58 05 A 9 Satellite Data Packets The following packets contain a variety of GPS satellite data Table 8 Satellite Date Packet Data I O Descriptions Input ID Description Output ID 0x27 request signal levels 0x47 0x28 request GPS system message 0x48 0x38 request load satellite system data 0x58 0x39 set request satellite disable or ignore health 0x59 Ox3A auto request last raw measurement Ox5A 0x3C request tracking status 0x5C auto Synchronized Measurement measurement packet Ox6F A 10 Background Packets The receiver automatically outputs a set of packets that the user may want to monitor for changes in receiver operations These messages are output at the rates indicated in the table below Table A 9 Background Packet Output Messages Output ID Description Notes 0x41 GPS tim
77. E 1 NMEA 0183 E 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 Lassen SK8 The NMEA message structure is described below SIDMSG D1 D2 D3 D4 Dn CS CR LF The signifies the start of message ID The talker identification is a two letter mnemonic which describes the source of the navigation information The GP identification signifies a GPS source MSG The message identification is a three letter mnemonic which describes the message content and the number and order of the data fields 6699 Commas serve as delimiters for the data fields Dn Each message contains multiple data fields Dn which are delimited by commas ee 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 delimiters is limited to 74 characters or less E 3 NMEA 0183 Message Options gt lt
78. Filter The Position Velocity PV Filter is the main filter and is used to soften the effect of constellation switches on position fixes The filter has no effect on velocity output and there is no lag due to vehicle dynamics There may be a small increase in accuracy however A feature of the PV filter is the static filter which engages when the receiver is moving very slowly This feature improves accuracy in the urban environment The PV filter should be turned off for the following applications Slow moving environments such as walking or drifting with the current When rooftop testing of receivers for moving applications The altitude filter is a simple averaging filter with a time constant of a few seconds It should be left on in marine and land applications To query for the current settings Command 0x70 is sent with no databytes To input new settings Command 0x70 is sent with four data bytes as shown in Table A 59 Also see A 3 for information on saving the settings to non volatile memory Table A 59 Command and Report Packet 0x70 Field Descriptions Byte Item Item Type Bit Number 0 PV Filter BYTE 0 Off 1 On 1 Static Filter BYTE 0 Off 1 On 2 Altitude Filter BYTE 0 Off 1 On 3 Reserved BYTE A 17 51 Report 0x70 This report is sent as a response to Command 0x70 as either a query or a set It contains four bytes as shown in Table A 59 A 54 Lassen SK8 Embedded GPS Module Tr
79. II Interface Protocol TAIP C 1 Message Format C 1 1 C 1 2 P 2 All TAIP communication uses printable uppercase ASCII characters The interface provides the means to configure the unit to output various sentences in response to queries or on a scheduled basis Each sentence has the following general format ABB C ID DDDD FF lt where Table C 1 Message Formats gt Start of new message Message qualifier BB a two character message identifier data string DDDD Optional 4 character vehicle ID FF Optional 2 character checksum lt delimiting character x signifies that x can occur any number of times x signifies that x may optionally occur once Start of a New Message The gt character ASCII code 62 decimal is used to specify the start of a new sentence Message Qualifier A one character message qualifier is used to describe the action to be taken on the message The following table lists the valid qualifiers Table C 2 Message Format Qualifiers Qualifier Action Q Query for a single sentence sent to GPS sensor R Response to a query or a scheduled report from the sensor F Schedule reporting frequency interval in seconds S Set command to download time to the GPS receiver D Specify a minimum distance traveled and a minimum and maximum time interval for the next report Details on the use of message qu
80. K8 can maintain lock on signals with SNRs as low as 0 it offers excellent performance when traveling through heavy foliage Multi reflected signals also known as Multi path can degrade the position solution Multi path is most commonly found in urban environments with many tall buildings and a preponderance of mirrored glass which is popular in modern architecture Multi reflected signals tend to be weak low SNR value since each reflection attenuates the signal By setting the SNR mask to 2 or higher the impact of multi reflected signals is minimized PDOP Mask Position Dilution of Precision PDOP is a measure of the error caused by the geometric relationship of the satellites used in the position solution Satellite sets which are tightly clustered or aligned in the sky will have a high PDOP and will contribute to a lower position accuracy For most applications a PDOP mask of 10 offers a satisfactory trade off between accuracy and GPS coverage time With world wide GPS coverage now available the PDOP mask can be lowered even further for many applications without sacrificing coverage For differential GPS applications PDOP related error can be the major contributor to position error For differential GPS applications requiring the highest level of accuracy the PDOP mask should be set to 7 or below Lassen SK8 Embedded GPS Module Operation and Performance 4 3 4 P PDOP Switch The default positioning mode for the Lassen
81. LOW THE LIMITATION OR EXCLUSION OF LIABILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES SO THE ABOVE LIMITATIONS MAY NOT APPLY TO YOU Software and Firmware Limited Warranty Trimble warrants that Software and Firmware products will substantially conform to the published specifications provided it is used with the Trimble products computer products and operating system for which it was designed For a period of ninety 90 days commencing thirty 30 days after shipment from Trimble Trimble also warrants that the magnetic media on which Software and Firmware are distributed and the documentation are free from defects in materials and workmanship During the ninety 90 day warranty period Trimble will replace defective media or documentation or correct substantial program errors at no charge If Trimble is unable to replace defective media or documentation or correct program errors Trimble will refund the price paid for The Software These are your sole remedies for any breach in warranty Hardware Limited Warranty Trimble Navigation Limited products are warranted against defects in material and workmanship for a period of one year The warranty period shall commence thirty 30 days after shipment from Trimble s factory Warranty service will be provided at a designated Trimble Service Center Trimble will at its option either repair or replace products that prove to be defective The Customer shall pay all shipping charges for products returned
82. Lassen SK8 3 2 3 4 Protocol Summary es 3 3 3 4 1 TSIP Data Outp t ins fe eae oS ale ERU edu f USER 3 3 Configuring the SK 8 receiver output protocol from TSIP to TAIP protocol 3 4 3 4 2 TAIP Data Output 22k ERASE PR Re ee es 3 5 Configuring the SK 8 receiver output protocol from TAIP to TSIP protocol TAIP message PR um sese ede aS Gog ae mE e ac eS 3 6 3 4 3 NMEA 0183 Data 3 6 3 5 Timing pplications s eg 3 7 3 5 1 Effect of GPS Week Number Roll over 3 7 Lassen Palisade Family Firmware Version 7 xx Software Modifications 3 8 3 6 Differentia GPS 2 5 55 oe YA ee es ee ae Be 3 8 Operation and Performance 4 1 GPS Satellite Message ne 4 1 4 2 Satellite Acquisition and Time to First Fix eee 4 2 4 2 1 Cold Starts 2 oko dt codo Ne bete st Ete 4 2 4 2 2 Watt Starts RON o Te eT rabo TERRE DR a 4 2 4 2 3 Garage Search Strategy ooo 4 3 4 2 4 Oty tar tet s dra fetus ARES oie MD daos PAD aut Gens 4 3 4 3 Satellite MaskSettings 2s 4 3 4 3 1 Eleva ion Mask ee 4 4 4 3 2 SNBEMAaSkE eta OS quieta Ud oed FOR edes 4 4 4 3 3 2 0 inp at o erg odit etatis Mose 4 4 4 3 4 PDOP Switch uuum ERES Rome we MEGA m
83. Lassen SK8 M Embedded GPS Module System Designer Reference Manual Part Number 34149 01 Firmware 7 20 7 52 Date August 1997 Trimble Navigation Limited Commercial Systems Group 645 North Mary Avenue Post Office Box 3642 Sunnyvale CA 94088 3642 U S A 1 800 827 8000 in North America 1 408 481 8000 International FAX 41 408 730 2082 U S Technical Assistance and Repair 1 800 SOS 4 TAC in North America 1 408 481 6940 International FAX 1 408 481 6020 European Technical Assistance and Repair 44 1256 1622 858 421 Copyrights 1997 Trimble Navigation Limited All rights reserved No part of this manual may be copied photocopied reproduced translated or reduced to any electronic medium or machine readable form without prior written consent from Trimble Navigation Limited Printed in the United States of America Printed on recycled paper Revision Notice This is the first release of the Lassen SKS Embedded GPS Module System Designer Reference Manual Part Number 34149 01 August 1997 This manual supersedes the Lassen SK8 GPS Board for Embedded Applications System Designer Reference Manual Part Number 29473 00 Revision B June 1997 O 1996 Trimble Navigation Limited Trademarks SVeeSix SVeeSix CM3 LASSEN SK8 Acutis Acutime Acutimell and TSIP are trademarks of Trimble Navigation Limited IBM is a registered trademark of International Business Machines Inc MS DOS and Windows is a trademark
84. Module A 17 41 Report Packet 0x5C Trimble Standard Interface Protocol 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 0x3C The data format is shown in Table 49 Table A 49 Byte Item Type Units Report Packet 0x5C Data Formats Value Meaning Byte 0 Satellite PRN number BYTE number 1 32 Byte 1 Channel code BYTE Bit 4 6 channel number 0 7 Bit position within byte 1 7 MSB channel number beginning with 0 Byte 2 Acquisition flag Byte 2 value 0 never acquired 1 acquired 2 re opened search Byte 3 Ephemeris flag Byte 3 value 0 flag not set good ephemeris for this satellite 4 hours old good health Byte 4 7 Signal level SINGLE same as in Packet 0x47 Byte 8 11 GPS time of last measurement SINGLE seconds Byte 8 11 value 0 no measurements have been taken Byte 12 15 Elevation SINGLE radians 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 typically about every 3 to 5 minutes Used for computing measurement correction factors Byte
85. P mask and DOP switch If this is not possible then the receiver attempts to obtain a 2 D solution with a DOP less than the DOP mask This mode supplies fairly continuous position fixes even when there is frequent obscuration This mode is preferable for most land or air applications where altitude changes are occurring and there is occasional obscuration The highest accuracy fix mode is 3 D manual where altitude is always calculated along with the latitude longitude and time However this requires four satellites with a PDOP below the DOP mask set in Packet BB in order to obtain a position Normally this will provide the most accurate solution Thus if only 3 D solutions are desired then the user should request 3 D manual mode Depending on how the PDOP mask is set this may be restrictive when the receiver is subjected to frequent obscuration or when the geometry is poor due to an incomplete constellation Alternatively if the user only wants a 2 D solution then 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 However any error in the assumed altitude will affect the accuracy of the latitude and longitude solution High accuracy users should avoid the 2 D mode and should expect fixes with accuracies which are at best as accurate as the supplied altitude If a marine user enters sea level as the altitude then small errors in the horizont
86. Parity TAIP is the default TAIP Odd b Press Enter 9 Set Stop Bits X a Select the appropriate Stop Bits TAIP is the default TAIP 8 b Press Enter Lassen SK8 Embedded GPS Module Software Interface 10 Set the Flow Control a Press the SPACE BAR to cycle through the options b Select the appropriate Flow Control TAIP is the default TAIP Off c Press Enter 11 Set Protocol In a Press the SPACE BAR to cycle through the options b Select TAIP 0 c Press Enter 12 Set Protocol Out a Press the SPACE BAR to cycle through the options b Select TAIP 0 c Press Enter 13 If satisfied with these selections a Press Y Saves the configuration b Press N Aborts the configuration and displays the message ABORTED 3 4 2 TAIP Data Output The Trimble ASCII Interface Protocol TAIP is a Trimble specified digital communication interface based on printable ASCII characters over a serial data link TAIP interface provides the means to configure the Lassen SK8 receiver to output various sentences in response to query or on a scheduled basis TAIP messages may be scheduled for output at a user specified rate starting on a given epoch from top of the hour For communication robustness the protocol optionally supports checksums on all messages It also provides the user with the option of tagging all messages with the unit s user specified identification number ID This greatly enhances the func
87. RPV15714 3739438 1220384601512612 ID 1234 7F lt DX Note The time given in the message is the time of the last GPS fix 04 21 54 GPS not necessarily the time of the message response If the time of last fix is 10 or more seconds old the age flag will be set to 1 Lassen SK8 Embedded GPS Module C 29 Trimble ASCII Interface Protocol TAIP C 30 Lassen SK8 Embedded GPS Module GPSSK User s Guide TAIP The TAIP Tool Kit known as GPSSK is a software package available from Trimble Navigation to assist users of the Trimble ASCII Interface Protocol TAIP GPSSK supports all Trimble sensors that use TAIP GPSSK can be used to setup diagnose and monitor your sensor and provides the following capabilities Program the GPS sensor for automatic message reporting and verify the success of the programming G Quickly program Vehicle ID numbers into a fleet of sensors Log the GPSSK session with the GPS sensor to disk and replay the data On screen plotting of GPS positions from the sensor Poll for and view combinations of TAIP messages Set different polling intervals for each message type Conduct an interactive terminal session with the GPS sensor Note The information about GPSSK this document is presented as a general overview The GPSSK distribution diskette includes a READ ME file that details the most current information about GPSSK functions and on loading and using GPSSK The GPSSK
88. Report Packet 0x58 Ephemeris Data Continued Byte Item Type Meaning ICD 200 Sec 25 28 a_f2 SINGLE Sec 20 3 3 3 Table 20 1 29 32 a f SINGLE Sec 20 3 3 3 Table 20 1 33 36 a f0 SINGLE Sec 20 3 3 3 Table 20 1 37 40 SVacc SINGLE Sec 20 3 3 3 Table 20 1 41 IODE BYTE Sec 20 3 3 4 42 fit_interval BYTE Sec 20 3 3 4 43 46 C_rs SINGLE Sec 20 3 3 4 47 50 delta_n SINGLE Sec 20 3 3 4 51 58 M 0 DOUBLE Sec20 3 3 4 59 62 C uc SINGLE Sec 20 3 3 4 radians 63 70 e DOUBLE Sec20 3 3 4 71 74 C us SINGLE Sec 20 3 3 4 radians 75 82 sqrt_A DOUBLE Sec 20 3 3 4 83 86 t_oe SINGLE Sec 20 3 3 4 87 90 C_ic SINGLE Sec 20 3 3 4 radians 91 98 OMEGA 0 DOUBLE Sec20 3 3 4 99 102 C is SINGLE Sec 20 3 3 4 radians 103 110 i 0 DOUBLE Sec20 3 3 4 111 114 C rc SINGLE Sec 20 3 3 4 115 122 omega DOUBLE Sec 20 3 3 4 123 126 OMEGADOT SINGLE Sec 20 3 3 4 127 130 IDOT SINGLE Sec 20 3 3 4 131 138 Axis DOUBLE sqrt_A 139 146 n DOUBLE derived from delta n 147 154 rime2 DOUBLE sart 1 0 e 155 162 OMEGA_n DOUBLE derived from OMEGA_0 OMEGADOT 163 170 ODOT_n DOUBLE derived from OMEGADOT Note All angles radians Note If data is not available byte 3 is set 0 and data is sent Lassen SK8 Embedded GPS Module A 43 Trimble Standard Interface Protocol A 44 A 17 39 Report Packet 0x59 Normally the GPS receiver selects onl
89. S 2 2D DGPS 3 30 DGPS 6 DR 8 Degraded DR 9 Unknown Age of Data Indicator 1 n a 2 Fresh lt 10 sec 1 Old gt 10 sec 0 Not available Total 30 Position is in latitude positive north and longitude positive east WGS 84 Heading is in degrees from True North increasing eastwardly The GPS time of day is the time of fix rounded to the nearest second Note The data this message is to be considered invalid and should not be used if the Age of Data Indicator is equal to 0 signifying data not available Lassen SK8 Embedded GPS Module C 19 Trimble ASCII Interface Protocol TAIP C 18 RM Reporting Mode C 20 Data String Format ID FLAG A CS FLAG B EC FLAG C FR FLAG D CR FLAG E Table C 18 Reporting Mode Data String Descriptions Item of Char UNITS Format Value ID Flag 1 n a A T True F False CS Flag 1 n a B T True F False EC Flag 1 n a T True F False FR Flag 1 n a D T True F False CR Flag 1 n a E T True F False ID Flag determines whether the unit is to include the vehicles ID with each report CS Flag determines whether the unit is to include a checksum as part of each message EC Flag when set will cause the unit to echo back all complete and properly formatted set commands except for DC and DD with a Response qualifier This provides an easy way to verify
90. SK8 Overview NIZ The Lassen SK8 is a complete 8 channel parallel tracking GPS receiver designed to operate with the L1 frequency Standard Position Service Coarse Acquisition code Using two highly integrated Trimble custom integrated circuits the receiver is designed in a modular format especially suited for embedded applications The Lassen SK8 features Trimble s latest signal processing code a high gain RF section for compatibility with standard 25 dB active gain GPS antennas and a CMOS TTL level pulse per second PPS output for timing applications or as a general purpose synchronization signal The Lassen SK8 acquires a position fix with minimal delay after power cycling The information necessary to help track satellites is stored in RAM using backup power for the following e Almanac Ephemeris Real time clock Last position User settings including port parameters and receiver processing options are stored in a non volatile electrically erasable ROM EEROM that does not require backup power The Lassen SK8 has two independently configurable serial I O communication ports Port 1 is a bi directional control and data port utilizing the Trimble Standard Interface Protocol TSIP or Trimble ASCII interface protocol TAIP Port 2 is a bi directional port used to receive differential GPS DGPS corrections in industry standard RTCM SC 104 format and for output of industry standard ASCII NMEA sentences The dual data I O port cha
91. SK8 is Automatic In this mode the receiver attempts to generate a 3 dimensional 3D position solution when four or more satellites meeting the mask criteria are visible If such a satellite set cannot be found the receiver will automatically switch to 2 dimensional 2D mode The PDOP switch establishes the trade off between 3D positioning and PDOP With the PDOP Switch set to 6 the receiver will compute a 2D position with a HDOP below 6 rather than a 3D position with a PDOP greater than 6 even when four or more satellites are visible Note PDOP Switch is only used in Auto mode If the PDOP Switch is greater than the PDOP Mask it will stay in 3D mode 4 4 Standard Operating Modes 4 4 1 The tracking mode controls the allocation of the receiver s tracking channels and the method used for computing position fixes The output of GPS data is controlled by two operating modes Fix Modes 2D 3D or Automatic Differential GPS Mode On Off or Auto Each of these operating modes is described below Fix Modes The Lassen SK8 offers three positioning modes 2D Manual 3D Manual and Automatic 2D 3D Automatic 2D 3D is the default mode for the Lassen SK8 The positioning mode can be modified in receivers accepting TSIP commands See Appendix A for more information on the TSIP protocol 2D Manual In 2D Manual mode the Lassen SK8 will only generate 2 dimensional 2D position solutions latitude and longitude only regardless
92. Section A 18 for information on Packets Ox8E and Ox8F A 58 Lassen SK8 Embedded GPS Module A 17 59 Command Packet 0xBB In query mode Packet OxBB is sent with a single data byte and returns Report Packet OxBB Table A 67 Item Trimble Standard Interface Protocol Meaning Command Packet 0xBB Query Mode Data Format Default Subcode Query mode TSIP Packet OxBB is used to set GPS Processing options The table below lists the individual fields within the OXBB Packet See A 3 for information on saving the settings to non volatile memory Table A 68 Item Meaning Command and Report Packet 0xBB Field Descriptions Default Subcode 0x03 Operating Dimension Automatic 2D 3D Horizontal 2D Full Position 3D Automatic DGPS Mode DGPS off DGPS only DGPS auto DGPS auto Dynamics Code Land Sea Air Stationary Reserved Not used Elevation Mask SINGLE Lowest satellite elevation for fixes radians AMU Mask SINGLE Minimum signal level for fixes DOP Mask SINGLE Maximum DOP for fixes DOP Switch SINGLE Selects 2D 3D mode Reserved Not used DGPS Age Limit Maximum time to use a DGPS correction seconds Reserved Lassen SK8 Embedded GPS Module Not used A 59 Trimble Standard Interface Protocol A 17 60 Report Packet 0xBB TSIP Packet OxBB is used to report the GPS Process
93. User s Guide Appendix C Trimble ASCII Interface Protocol TAIP Appendix D GPSSK User s Guide TAIP Appendix E NMEA 0183 Appendix F Specifications and Mechanical Drawings Glossary The Lassen SK8 is easy to integrate and simple to use Before proceeding with Chapter 1 please review the information contained in this Preface for an overview of the Global Positioning System Technical Assistance XX If you have problems and cannot find the information you need in this document call the Trimble Technical Assistance Center TAC The phone numbers are 1 800 SOS 4TAC North America 1 408 48 1 6940 International 1 408 48 1 6020 FAX You call the Technical Assistance Center phones between 6 AM 0600 to 5 30 PM 1730 Pacific Standard Time A support technician will take your call help you determine the source of your problem and provide you with any technical assistance you might need You can send email to the Technical Assistance Center at any time A support technician will respond to your email questions or comments The email address is trimble_support trimble com Lassen SK8 Embedded GPS Module Preface Worldwide Web Check the Trimble worldwide web site on the Internet http www trimble com for the latest news on new products and releases Internet FTP Address You can visit the Trimble Public FTP site at any time to access software patches utilities service bulletins and FAQs The FTP site ad
94. a transmission Baud and bit rate are the same for direct equipment interconnections e g via 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 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 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 in a 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 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 i
95. able is not provided in the kit since this cable is country specific The input connector is a standard 3 prong connector used on many desktop PCs Figure 1 9 AC DC Power Converter 1 5 Hardware Setup The Lassen SK8 supports TSIP TAIP and NMEA protocols Port 1 is used for TSIP or TAIP I O and port 2 is used to input RTCM corrections and output NMEA messages Follow the steps below to setup the Starter Kit Figure 1 10 illustrates the setup 1 For TSIP or TAIP Protocols connect one end of the 9 pin serial interface cable to Port 1 or Port 2 to view NMEA data of the receiver module Connect the other end of the cable to COMI or COM2 on a PC A 9 pin to 25 pin adapter may be required for the serial interface connection to a PC if your PC has a 25 pin communication port Connect the antenna cable to the interface unit This connection is made by pushing the antenna cable connector onto the SMB connector on the unit to remove the antenna cable simply pull the antenna connector off of the SMB connector Place the antenna so that it has a clear view of the sky Using either the DC power cable or AC DC power converter connect to the 3 pin power connector on the interface unit DC Power Cable Connect the terminated end of the power cable to the power connector on the interface unit Connect the red lead to DC positive voltage 9 to 32 VDC and black power lead to DC ground The yellow wire is not used Switch on the DC pow
96. ace Protocols ie 65 rette ies IG oi Pes 1 3 PORCE ae S PS i ic mer Aon ds 1 3 oe Aus tos MISI doses TAY 1 3 1 1 2 Starter Kit Components eA 1 3 1 2 GPS Receiver Module x 2 Veg A ewe ee Bee D 1 5 123 dede cete gU exe eue gd a we UN SUN 1 8 l4 SPO WOR ge wx ay eat bg TID e Res ee Ge he GEO dy HO Bey GR 1 9 1 5 Hardware Setup eode cosi i e ae alea E eiae D e E A a e ee E 1 10 1 6 Running the TSIP Interface 1 11 2 Hardware Integration 2 1 The Lassen SK8 Receiver 2 1 2 2 Interface Connector ses le 2 3 2 3 Power Requirement 2 eb ee ee be he ed 2 3 2 4 Serial Interface ec usse bo obesse AL gh a td 2 4 2 5 P lse PerSecond soro aoaaa 2 222 2 5 2 6 Mo ntinig cuv as Ba es eels duy dee doe ibus 2 5 21 REShield s 2 i on Gh sad e eee ee does ce ale betes d we god 2 5 Lassen SK8 Embedded GPS Module vi Software Interface SATUD uoo eoe e eth e ER al Wig ne Gedy tw text ah ee 3 1 3 2 Software LOOL RITS gaspi Rue we ee ta ACA Sete Pues 3 1 33 Communicating with the
97. acket Ox8F 20 This packet provides complete information about the current position velocity fix in a compact fixed length 56 byte packet The fields are fixed point with precision matched to the receiver accuracy It can be used for automatic position velocity reports The latest fix can also be requested by Ox8E 20 or 0x37 commands The data format is shown below Table A 82 Report Packet 0x8F 20 Data formats Type Meaning Sub packet id BYTE KeyByte BYTE east velocity INTEGER north velocity INTEGER Id for this sub packet always 0x20 Reserved for Trimble DGPS Post processing units 0 005 m s or 0 020 m s see Byte 24 Overflow 0x8000 units 0 005 m s or 0 020 m s see Byte 24 Overflow 0x8000 Lassen SK8 Embedded GPS Module A 67 Trimble Standard Interface Protocol A 68 Table A 82 Report Packet 0x8F 20 Data formats Continued up velocity INTEGER units 0 005 m s or 0 020 m s see Byte 24 Overflow 0x8000 Type Meaning Time Of Week UNSIGNED LONG INTEGER GPS Time in milliseconds Latitude LONG INTEGER 31 WGS 84 latitude units 2 semicircle Range 2 to2 Longitude UNSIGNED LONG INTEGER 31 WGS 84 longitude east of Meridian units 2 semicircle Range 0 to 2 Altitude LONG INTEGER Altitude above WGS 84 ellipsoid mm Velocity Scaling When bit 0 is set to 1 velocities in bytes 2 through 7 have been sc
98. al solution will occur when the sea state is rough or there are high tidal variations However these errors may be smaller than the altitude errors induced by SA so 2 D may be preferable for a marine user who does not want to observe unusual altitudes A 15 2 Dynamics Code The feature 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 reverts to user entered altitude in 2 D auto In AIR mode the search and re acquisition routines are optimized for high acceleration conditions A 15 3 Elevation Mask This is the minimum elevation angle for satellites to be used in a solution output by the receiver Satellites which are 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 generally 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 Lassen SK8 Embedded GPS Module A 17 Trimble Standard Interface Protocol A 15 4 A 15 5 A 18 Frequent constellation switching is unde
99. aled by 4 Reserved Datum Datum index 1 0 unknown Fix Type BYTE Type of fix This is a set of bit flags 0 LSB 0 Fix was available No fix available Fix is autonomous Fix was corrected with RTCM 3D fix 2D fix 2D fix used last calculated altitude 2D fix used entered altitude 0 unfiltered 1 position or altitude filter on 5 7 not used 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 Lassen SK8 Embedded GPS Module Table A 82 Type Meaning Trimble Standard Interface Protocol Report Packet 0x8F 20 Data formats Continued FIX SVs Repeated groups of 2 bytes one for each satellite There will always be 8 of these groups The bytes are 0 if group N A The following table describes the contents of each group lono Params 8 CHARS The broadcast ionospheric parameters Table A 83 Report Packet 0x8F 20 Fix SVs field 32 47 Byte Item Type Bit Number Meaning 32 BYTE 0 5 PRN 6 7 IODC IODE 256 33 BYTE 0 7 IODE A 18 10 Report Packet Ox8F 26 This report will be issued after an Ox8E 26 command Table A 84 Report Packet Ox8F 26 Field Descriptions Byte Item Item Type Bit Number Meaning 0 Subcode BYTE 0x26 Save Settings 1 4 Status U32 Reserved
100. alifiers are given in the last section of this appendix Communication Using TAIP Note All TAIP message characters must be in uppercase Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP C 1 3 C 1 4 C 1 5 C 1 6 C 1 7 Message Identifier A unique two character message identifier consisting of alphabetical characters is used to identify type messages For example PR for Protocol or VR for Version Number Data String The format and length of a data string is dictated by the message qualifier and the message identifier The data string may contain any printable ASCII character with the exception of the gt lt and characters Detailed descriptions of each message format are provided in the specific message sections of this Appendix Most messages are length sensitive and unless otherwise specified field separators including spaces are not used Vehicle ID A vehicle identification ID may optionally be used in all the communications with the sensor Each sensor in the fleet may be assigned a four character alpha numeric ID and be forced to output that ID in all messages The default is ID set to 0000 and the ID Flag set to F false The sensor will check all incoming messages for ID If no ID is specified the sensor will accept the message If the ID is included in messages but does not compare with the ID previously set the message will be ignored This applies even when the ID Flag is t
101. allows you to control which position and velocity packets are output Table A 3 Automatic Position and Velocity Reports Control Setting Bits Packet Byte 0 Byte 0 ByteO ByteO Byte1 Byte 1 ID Description Bit 0 Bit 1 Bit 4 Bit 5 Bit 0 Bit 1 0x42 single 1 0 precision XYZ position 0x83 double 1 1 precision XYZ position 4 single 1 0 precision LLA position 0x84 double 1 1 precision LLA position 0x43 velocity fix 1 XYZ ECEF 0x56 velocity fix 1 ENU Ox8F 17 Single 0 1 Precision Ox8F 18 Single 0 1 Precision ELEF Ox8F 20 LLA amp ENU 1 Lassen SK8 Embedded GPS Module A 5 Trimble Standard Interface Protocol A 5 Warm Start Packets If the receiver is connected to a back up power source such as a lithium battery the data required to cause a warm start is retained even when main power is turned off Before power off check the following automatic outputs to ensure a warm start will occur on the next power on cycle The value of Packet Ox4B byte 1 bit 3 is 0 which indicates that the almanac is complete and current The position input 0x42 4A 0x83 0x84 Ox8F 17 Ox8F 18 Ox8F 20 are correct See Table A 4 The time in Packet 41 is correct Turning on main power will cause a warm start If however you are not supplying the receiver with battery power when main power is off you can still warm start the receiver by sending the following
102. am is translated into an ASCII file with the program TSIPPRNT Lassen SK8 Embedded GPS Module B 3 TSIP User s Guide Quick Start Almanac Get and Load Setting PC Time from the Receiver Exiting TSIPCHAT B 4 A stored almanac can allow the receiver to be warm started reducing time to first fix If the receiver is started cold with no almanac data in memory it performs a search for satellites in the sky which can take a few minutes If the receiver has a recent almanac of satellite orbits fixes begin within a minute The receiver responds most quickly if loaded with time frequency offset last position and a recent almanac There is a command sequence for getting an almanac from the receiver and storing in a file named GPSALM DAT and a reverse command sequence for reading a file named GPSALM DAT on the computer and loading it into the receiver These command sequences use the Packet 0x38 and the Report Packet 0x58 Use the exclamation point for the get and store sequence and the at symbol for the read and load sequence It is useful to record a fresh almanac every few days A new almanac is available after the receiver has been operating continuously for about fifteen minutes Check the health message to see that Almanac not complete and current is no longer reported before recording the almanac TSIPCHAT includes the capability to set the PC clock to UTC time from the GPS satellite signal GPS time differs fr
103. ant 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 useful 1 2 3 4 5 The illustrations are clear and helpful 1 2 3 4 5 The manual is toolong 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 the local office listed on the back cover or to Trimble Navigation Limited Software Component Technologies Marketing Group 645 North Mary Avenue Post Office Box 3642 Sunnyvale CA 94088 3642 USA All comments and suggestions become the property of Trimble Navigation Limited
104. assen SK8 is installed on an interface motherboard which is housed in a metal enclosure see Figure 1 1 This packaging simplifies testing and evaluation of the module by providing an RS 232 serial interface which is compatible with most PC communication ports and by providing a DC power supply which converts a 9 to 32 volts DC input to the regulated 5 volts required by the module The DB9 connectors provide an easy connection to the PC s serial port using the interface cable provided in the kit The metal enclosure protects the module and motherboard for testing outside of the laboratory environment Figure 1 1 Module Installed Inside the Interface Unit Lassen SK8 Embedded GPS Module 1 5 Starter Kit The receiver module see Figure 1 2 consists of a single 3 25 x 1 25 x 0 40 module A standard SMB RF connector J1 supports the GPS antenna connection The center conductor supplies 5 VDC for the Low Noise Amplifier of the active antenna An 8 pin 0 1 inch header J4 supports the serial interface CMOS TTL level the pulse per second PPS signal CMOS TTL level and the input power 5 VDC This module connects to the motherboard via the 8 pin header and is secured by two standoffs An RF interface cable connects the antenna port to an SMB connector on the enclosure panel Antenna Connector Fin Header Figure 1 2 Receiver Module Note The receiver included in the Starter Kit contains a socket for the firmware
105. ata format is shown below Table A 27 Report Packet 0x42 Data Formats Type Units 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 Packet 83 provides a double precision version of this information A 17 24 Report Packet 0x43 This packet provides current GPS velocity fix in XYZ ECEF coordinates If the I O velocity option is set to XYZ ECEF then the GPS receiver sends this packet each time a fix is computed The data format is shown below Table A 28 Report Packet 0x43 Data Formats Item Type Value 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 30 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 17 25 Report Packet 0x45 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 0 1 Table A 29 Report Packet 0x45 Data Formats Item U lt Major version number Minor version number Month Day Year number minus 1900 Major revision number Minor revision number Month Day 0 1 2
106. ble C 14 Table C 15 Table C 16 Table C 17 Table C 18 Table C 19 Table C 20 Table C 21 Table C 22 Table C 23 Table C 24 Table C 25 Table C 26 Table E 1 Table E 2 Table E 3 Table E 4 Table E 5 Table E 6 Table E 7 Table E 8 Table E 9 xviii Long Navigation Message Data String Descriptions C 16 PR Data String C 17 Port Characteristic Data String Descriptions llle C 18 Position Velocity Solution Data String Descriptions C 19 IReporting Mode Data String Descriptions lens C 20 Reset Mode Data String Descriptions C 21 IData Sting Hex Characters een C 22 Tracking Status Codes iosa s 222A C 22 Error Codes Nibble 1 Ryu sO ee GA Ue UR VERS C 23 Error codes Nibble 2 m Ve Rete coru as Re eee C 23 ErrorCodes Nibble4 45d Swe Eee eae wa Bed C 24 TM Time Data Data String C 25 Version Number Data String C 26 NMEA 0183 Characteristics en E 1 Lassen SK8 NMEA E 3 GGA GPS Fix Data Message Parameters E 3 GLL Geographic Position Latitude Longitude Message Parameters E 4 GSA GPS DOP and Active Satellites Message Parameters E 4 GSV GPS Satellites in View Messag
107. by the Lassen SK8 is a CMOS TTL level signal If this signal must be furnished to a remote location the system designer should provide an RS 422 driver for the timing pulse When the Lassen SK8 is installed on the interface motherboard supplied in the Starter Kit the PPS signal is connected to an open collector circuit and the polarity of the signal is inverted 4 10 System Architecture The Lassen SK8 module see Figure 4 1 uses eight processing channels operating on the L1 frequency of 1575 42 MHz and using the coarse acquisition C A code The module uses custom integrated circuitry designed by Trimble to track the GPS satellite signals These ICs also contain support circuitry to the navigation processor An integrated 32 bit microprocessor is used for tracking computing a position and performing the I O operations The module receives the GPS satellite signals through the antenna feed line connector amplifies the signals and then passes them to the RF down converter A highly stable crystal reference oscillator operating at 12 504 MHz is used by the down converter to produce the signals used by the 8 channel signal processor The 8 channel signal processor tracks the GPS satellite signals and extracts the carrier code information as well as the navigation data at 50 bits per second Operation of the tracking channels is controlled by the navigation processor The tracking channels are used to track the highest eight satellites abov
108. cation specific software so the source code in ANSI C is included for many of these programs The OEM GPS Tool Kit program disk includes the following programs TSIPCHAT EXE reads TSIP reports and prints them to the screen It also allows the user to exercise TSIP commands by translating keystroke codes into TSIP commands which are output over the serial port When data input is required TSIPCHAT prompts the user for the information TSIPCHAT can also log TSIP reports in binary format and can set time on a PC based on time information from the GPS module Source code is provided TSIPPRNT EXE interprets a binary TSIP data stream such as logged by TSIPCHAT and prints it to a file Source code is provided RTCM_MON EXE monitors a serial port carrying RTCM differential corrections translates the messages and prints them to the screen TCHAT EXE provides a good working basis for GPS development Source code is provided The program is Microsoft Visual C and Borland C compatible This appendix provides explicit instructions for each of the programs contained in the OEM GPS Tool Kit and guidelines for using the source code as template for integrated systems applications Note The GPS Tool Kit diskette contains a self extracting ZIP file that installs a complete developer s environment within the hard disk directory you select Installation instructions are provided in the READ ME file on the diskette and in Chapter 1 of this ma
109. ck to week 0 Week 0 began January 6 1980 There will be another week 0 beginning August 22 1999 The extended GPS week number however does not cycle back to 0 For example August 22 1999 starts week number 1024 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 Ox41 and the Packet 0x46 status code Table A 26 Packets 0x41 and 0x46 Status Code Relationships Approximate Time Packet 46 Accuracy Time Source Sign TOW Status Code none no time at all 0x01 unknown approximate time 0x01 from real time clock or Packet 2E 20 50 msec clock drift time from satellite not 0x01 full accuracy time from GPS 0x00 solution DX Note Before using the GPS time from Packet 0x41 verify that the Packet 0x46 status code is 00 Doing position fixes This will ensure the most accurate GPS time Lassen SK8 Embedded GPS Module A 29 Trimble Standard Interface Protocol A 17 23 Report Packet 0x42 This packet provides current GPS position fix in XYZ ECEF coordinates If the I O position option is set to XYZ and the I O precision of position output is set to single precision then the GPS receiver sends this packet each time a fix is computed The d
110. commands after the receiver has completed its internal initialization and has sent Packet 82 see Table A 5 Table A 4 Warm Start Packet Commands INPUT Description 0x2B initial position Ox2E initial time 0x38 02 almanac for each SV 0x38 03 almanac health 0x38 04 ionosphere page 0x38 05 UTC correction A 6 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 6 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 which indicate the initial operating condition of the receiver Messages are output in the following order After Packet 82 is output the sequence is complete and the receiver is ready to accept commands Table A 5 Packet Power up Output Messages Output ID Description Notes 0x41 GPS time This Packet is only output if GPS time is available 0x45 software version 0x46 receiver health 0x4B machine code status As chosen see Table A 4 position Velocity output 82 DGPS position fix mode A 7 Differential GPS Packets For differential GPS applications you may need to implement the following TSIP control commands Table A 6 Differential GPS Packet TSIP Control Commands Input ID Description Output ID 0 Port configuration 0xBC 0x60 Differential GPS corrections types 1 and 9 0x61
111. cond available F 1 3 DGPS Accuracy Position 2 meters CEP 5096 without SA Selective Availability Velocity 0 05 m sec 1 Sigma steady state conditions without SA Time 500 nanosecond nominal F 1 4 Datum WGS 84 standard DMA datum set Lassen SK8 Embedded GPS Module F 1 Specifications and Mechanical Drawings F 1 5 Acquisition Rate Cold Start 3 minutes 9096 Warm Start lt 45 seconds 90 Hot Start 12 seconds 9096 F 1 6 Dynamics Altitude 1000 m to 18 000 m Velocity 515 m sec maximum Acceleration 4g 39 2 ise Jerk 20 ieee F 2 Environmental Characteristics F 2 1 Temperature Receiver board Operating 10 C to 60 C standard 400C to 850C optional Storage 55 C to 100 x GPS Antenna Operating 40 C to 85 C F 2 2 Vibration 0 008 fie 5Hz 20 Hz 0 05 20Hz 100Hz 3dB octave 100Hz 900Hz Specifications comply with SAE J1211 requirements F 2 3 Altitude 400 to 18 000 meters MSL F 2 4 Humidity 95 non condensing 60 2 Lassen SK8 Embedded GPS Module Specifications and Mechanical Drawings F 3 Physical Characteristics F 3 1 Size Receiver board 82 6 mm x 1 30 mm x 10 2 mm 3 25 x 1 25 x 0 40 Antenna 47 mm x 40 mm x 13 3 mm 1 85 x 1 58 x 0 52 F 3 2 Weight Receiver board 19 6 g 0 7 oz without optional shield Receiver board 36 4 g 1 3 oz with optional shield F 3 3 Power
112. d Stop Bits 1 Stop Bits 1 No Flow Control No Flow Control Baud Rate 9600 Baud Rate 9600 Data Bits 8 Data Bits 8 Parity Odd Parity Odd Stop Bits 1 Stop Bits 1 No Flow Control No Flow Control Baud Rate 4800 Baud Rate 4800 Data Bits 8 Data Bits 8 Parity None Parity None Stop Bits 1 Stop Bits 1 No Flow Control No Flow Control Any standard serial communications program such as Windows Terminal or PROCOMM can be used with the TAIP or NMEA interface protocol TSIP is a binary protocol and outputs raw serial data onto the screen which cannot be read Trimble encourages the use of the DOS compatible software tool kit provided for TSIP The serial port drivers in the Trimble tool kit TSIPCHAT match the Lassen SK8 serial port characteristics The TSIPPRNT program converts binary data logged with the TSIPCHAT program into ASCII characters that may be printed and displayed Warning When using the TSIP protocol to change port assignments or characteristics confirm that your changes do not affect the ability to communicate with the receiver module Lassen SK8 Embedded GPS Module Software Interface 3 4 Protocol Summary The Lassen SK8 receiver is shipped from the factory with the following configuration TSIP 9600 baud 8 odd 1 on Port 1 NMEA out RTCM in 4800 baud 8 none 1 on Port 2 The receiver can easily be reconfigured for other combinations of language and port baud rate and parity The
113. d Descriptions for Converting Ellipsoid ECFF XYZ to Coordinate System LLA llle A 65 Report Packet Ox8F 17 Field Descriptions llle A 66 Report Packet 8F 18 Field A 67 Command Packet Ox8F 19 Field Descriptions A 67 Report Packet Ox8F 20 A 67 Report Packet Ox8F 20 Fix SVs eA A 69 Report Packet Ox8F 26 Field Descriptions 0 0 A 69 Datum RE Er EM RENE IMPR od Eee eR e A 70 Message Formats dog hh e ot eR e oh te tase de eaten C 2 Message Format Qualifiers 0 0 C 2 Time and Distance Reporting Message Format Qualifiers C 4 Time and Distance Reporting Message Format Qualifiers C 5 Message Data String C 7 Altitude Up Velocity Data String Descriptions C 8 Auxiliary Port Characteristics Data String Descriptions C 9 Compact Position Solutions Data String Descriptions C 10 RTCM 104 Record Types 1 and 9 Data String Descriptions C 11 Delta Differential Corrections Data String Descriptions C 12 Delta Differential Corrections Data String Descriptions C 13 Identification Number Data String Descriptions C 14 Initial Position Data String C 15 Ta
114. des a DC power regulator which converts a 9 to 32 VDC input to the regulated 5 VDC required by the module Power can be applied to the Starter Kit module using one of two options the DC power cable see Figure 1 8 or the AC DC power converter see Figure 1 9 Rad Power Black mund Yellow Unused Figure 1 8 Power Cable The DC power cable is ideal for bench top or automotive testing environments The power cable is terminated at one end with a 3 pin plastic connector which mates with the power connector on the metal enclosure The unterminated end of the cable provides easy connection to a DC power supply Connect the red power lead to a source of DC positive 9 to 32 VDC and connect the black power lead to ground This connection supplies power to both the receiver module and the antenna The combined power consumption of the receiver module and the antenna is 200 milli amps Lassen SK8 Embedded GPS Module 1 9 Starter Kit P Note The yellow wire is not used in the Starter Kit Battery back up is provided by a factory installed 3 6V lithium battery on the motherboard The AC DC power converter may be used as an alternate power source for the Starter Kit module The AC DC power converter converts 110 or 220 VAC to a regulated 12 VDC compatible with the Starter Kit module The AC DC power converter output cable is terminated with a 3 pin connector compatible with the power connector on the metal enclosure The AC power c
115. dress 15 ftp trimble com pub sct embeded bin FaxBack FaxBack is a completely automated fax response system for selecting documents and catalogs lists of available documents to be faxed back to a fax machine Call from a tone dialing phone and FaxBack guides you through the call by playing a pre recorded voice message The FaxBack system is available 24 hours a day seven days a week You can order a variety of documents including data sheets application notes technical documentation configuration guides assembly drawings and general information To call the FaxBack service dial the following number and follow the instructions 1 408 481 7704 Reader Comment Form A reader comment form is provided at the end of this guide If this form is not available comments and suggestions can be sent to Trimble Navigation Limited 645 North Mary Avenue Post Office Box 3642 Sunnyvale CA 94088 3642 All comments and suggestions become the property of Trimble Navigation Limited Lassen SK8 Embedded GPS Module Preface Document Conventions Italics Software menus menu commands dialog boxes and fields SMALL CAPITALS DOS commands directories filenames and filename extensions Courier Represents what is printed on the computer screen Courier Bold Information that to be typed in a software screen or window Return or Ctrl C Identifies a hardware function key or key combination that must be pressed on a comp
116. e If the receiver s GPS clock is set and the receiver is not outputting positions time is output approximately every 5 seconds 0x46 Ox4B receiver health messages Receiver health messages are output every 5 seconds 0 6 mode packets Mode packets are output every second A 8 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 11 Backwards Incompatibility of Lassen SK8 Packets with Previous TSIP Versions Several new TSIP command packets have been made available with the release of the Lassen SK8 receiver module and some existing packets have been modified or are no longer supported Table A 10 identifies the backwards compatibility of auto output packets Table A 11 identifies the backwards compatibility of the TSIP command packets Unless otherwise noted the commands and their corresponding output packets are still supported in the firmware Table A 10 Supported Auto Output Packet Command Backward Compatibility Old Packet Control New Packet Control Notes 0x40 auto 0x58 02 0x38 02 no longer auto 0x44 auto 0 6 0 38 06 0x44 not supported 0x5A auto Ox6F auto 0x5B auto Ox5E auto Ox8F 01 auto Ox8F 02 0x58 06 no longer auto Ox5E not supported Ox8F 20 0x01 0x02 not supported Lassen SK8 Embedded GPS Module A 9 Trimble Standard Interface Protocol A 10 Lassen SK8 Embedded GPS Module
117. e Parameters E 5 RMC Recommended Minimum Specific GPS Transit Data Message Parameters E 6 Track Made Good and Ground Speed Message Parameters E 6 ZDA Time amp Date Message lt E 7 Lassen SK8 Embedded GPS Module Preface The Global Positioning System GPS is a satellite based navigation system operated and maintained by the U S Department of Defense The GPS consists of a constellation of 24 satellites providing world wide 24 hour three dimensional 3 D coverage Although originally conceived for military needs GPS has a broad array of civilian applications including surveying marine land aviation and vehicle navigation GPS is the most accurate technology available for vehicle navigation As a Satellite based system GPS is immune to the limitations of land based systems such as Loran Loran navigation is limited in coverage and is encumbered by adverse weather In addition the accuracy of Loran navigation varies with geographic location and even under ideal conditions cannot compare with GPS By computing the distance to GPS satellites orbiting the earth a GPS receiver can calculate an accurate position This process is called satellite ranging A 2 D position calculation requires three satellite ranges A 3 D position calculation which includes altitude requires four satellite ranges GPS receivers can also provide precise time speed and cour
118. e ee d Sod RR ROC ee Beg Wty and A 70 A 20 Reference Documents A 75 TSIP User s Guide Trimble ASCII Interface Protocol TAIP Message Format scos esc oe oh ew a C 2 C 1 1 Start of a New C 2 C 1 2 Message Qualifier om urge Rer deme RO xd eus C 2 C 1 3 Messageldentifier 22e 3 C 1 4 Data Stringi ma ose hg eg hg em ER eim S C 3 C 1 5 Vehicle ID 35 elo RS mutet te dps Geor dedi sar cm C 3 C 1 6 CHECKSUM 2215 5 iet eer tt obe eta t ale dote I ee dom d C 3 C 1 7 Message Delimiter uuo koe RU Ew obse C 3 G2 Sample PV Message i 3 wb XXE IO a Ld RIPE Ses us C 4 C 3 Time and Distance Reporting C 5 C 4 Latitude and Longitude C 6 C 5 MessageDataStrings 22s C 7 C 23 Communication Using C 27 C 23 1 Query for Single Sentence ole C 27 C 23 2 Response to Query or Scheduled Report C 27 C2333 The Set Qualifier i oki es nea a ae REOR ace C 28 C 23 4 Sample Communication Session C 28 GPSSK User s Guide TAIP D Th GPSSK Files L 2m A ee Bw 4 dem hue Dew SES D 1 D2 TAIP C Source Files soe es teed ow a Oe exce ect es ae Be D 2 10 3 GPSSK aoe ad Pee edo nal ae ea
119. e flattening f a b a where b is the length of the semiminor 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 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 of the deflection of the vertical at the origin and the geodetic azimuth of a line from the origin to some other
120. e list of datums is provided at the end of this appendix Eccentricity Squared is related to flattening by the following equation e op p Lassen SK8 Embedded GPS Module A 65 Trimble Standard Interface Protocol A 66 A 18 6 A 18 7 Report Packet Ox8F 17 This packet reports position in single precision UTM Universal Transverse Mercator format The UTM coordinate system is typically used for U S and international topographical maps The UTM coordinate system lays out a world wide grid consisting of the following 60 North South zones in 6 increments extending eastward from the International Date Line 10 East West zones divided in 8 increments extending above and below the Equator Coordinates within these boundaries cover all surface locations from 80 South to 84 North and encircle the earth Locations are indicated by offset from the equator and in the zones east of the International Date Line These offsets are known as Northing and Easting and are expressed in meters UTM is not usable in polar regions Table A 79 Report Packet 0x8F 17 Field Descriptions Byte Description Type Value 0 Subcode Byte 0x17 1 Gridzone Designation Char 2 3 Gridzone Integer 4 7 Northing Single Meters 8 11 Easting Single Meters 12 15 Altitude Single Meters 16 19 Clock Bias Single Meters 20 23 Time of Fix Single Seconds Report Packet Ox8F 18 This packet reports position in double precisio
121. e the horizon The navigation processor will then use the optimum satellite combination to compute a position The navigation processor also manages the ephemeris and almanac data for all of the satellites and performs the data I O Lassen SK8 Embedded GPS Module 4 11 Operation and Performance Base Band IF Filter Filter Band Pass Filter 12 504 MHz 12 504 MHz Oscillator CUSTOM IC RF IN From Active antenna 20 to 40 db gain Ant Pwr Protect Detect Prime Power 1PPS Backup Power Figure 4 1 Lassen SK8 Block Diagram 4 12 Lassen SK8 Embedded GPS Module A Trimble Standard Interface Protocol The Trimble Standard Interface Protocol TSIP provides the system designer with over 75 commands that may be used 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 This appendix provides the information needed to make judicious use of the powerful features TSIP has to offer to greatly enhance overall system performance and to reduce the total development time The reference tables beginning on Page 2 will help you determine which packets apply to your application For those applications requiring customizing see Page 3 for a detailed description of the key setup parameters Application guidelines are provided for each TSIP Command Packet begi
122. ected positions In manual DGPS mode the receiver only computes solutions if corrections are available for the selected satellites This is the most accurate mode but it is also the most selective since the fix density is dependent on the availability of corrections The applicability of corrections is determined by the maximum age which can be set using Packet OxBB The AUTO mode avoids the fix density problem but opens the possibility of going in and out of DGPS mode potentially resulting in position and velocity jumps In differential OFF mode the receiver will not use corrections even if they are valid If accuracy is critical use MANUAL DGPS mode If fix density is critical AUTO DGPS is the recommended mode A 16 Packet Structure TSIP packet structure is the same for both commands and reports The packet format is DLE id data string bytes DLE ETX Where DLE is the byte 0x10 e lt ETX gt is the byte 0x03 id is a packet identifier byte which can have any value excepting ETX and DLE The bytes in the data string can have any value To prevent confusion with the frame sequences DLE id and DLE lt ETX gt every DLE byte in the data string is preceded by an extra DLE byte stuffing These extra DLE bytes must be added stuffed before sending a packet and removed after receiving the packet Notice that a simple DLE ETX sequence does not
123. ed GPS Module Software Interface Alternatively you may use Trimble s TSIP packets 60h and 61h to apply differential corrections through the Lassen SK8 port 1 J4 pin 5 These packets can be interleaved with the TSIP command stream Packets 60h and 61h are useful in applications which require the use of a single communications channel between the Lassen SK8 and the system Note that using these messages requires you to reformat the RTCM SC 104 differential correction data into the 60h 61h message format See Appendix A for more information on these messages Lassen SK8 Embedded GPS Module 3 9 Software Interface 3 10 Lassen SK8 Embedded GPS Module 4 1 4 Operation and Performance This chapter describes the Lassen SK8 satellite acquisition and tracking processes performance characteristics and system architecture This discussion assumes that you are familiar with the basic theory of the Global Positioning System Before proceeding to the detailed discussion of the satellite acquisition and tracking process please review the GPS satellite message description on the next page The Lassen SK8 satellite acquisition and tracking algorithms can achieve a position solution without any initialization The receiver automatically selects and tracks the best combination of satellites to compute position and velocity As satellites move out of view the Lassen SK8 automatically acquires new satellites and includes them in the solution set as req
124. ed down for less than 60 minutes and the almanac position ephemeris and time 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 20 seconds 4 3 Satellite Mask Settings Once the Lassen SK8 has acquired and locked onto a set of satellites which pass the mask criteria listed in this section and has obtained a valid ephemeris for each satellite it will output regular position velocity and time reports according to the protocol selected The default satellite masks observed by the Lassen SK8 are listed in Table 4 1 These masks serve as the screening criteria for satellites used in fix computations and ensure that position solutions meet a minimum level of accuracy The Lassen SK8 will only output position course speed and time when a satellite set can be acquired which meets all of the mask criteria The satellite masks can be adjusted in GPS receivers accepting the TSIP protocol See the section titled Key Setup Parameters located in Appendix A Table 4 1 Default Satellite Mask Settings Mask Setting Elevation 5 SNR 2 PDOP 10 PDOP Switch 5 Lassen SK8 Embedded GPS Module 4 3 Operation and Performance 4 4 4 3 1 4 3 2 4 3 3 Elevation Mask Satellites below a 5 elevation are not used in the position solution Although low elevation satellites can contribute to a
125. ee satellites are visible which meet the mask criteria the Lassen SK8 will automatically switch to 2 dimensional 2D mode and will use the last calculated altitude if available or the default altitude in the position solution In 2D 3D Automatic mode the PDOP switch is active 4 5 Differential GPS Operating Modes 4 6 4 5 1 4 5 2 4 5 3 The default mode for the Lassen SK8 is DGPS Automatic The Lassen SK8 supports three DGPS Modes On Off and Automatic and the mode may be changed by issuing the appropriate TSIP command See Appendix A for information on TSIP commands The three DGPS operating modes are described below DGPS On When DGPS On is selected the Lassen SK8 will only provide differential GPS solutions If the source of correction data is interrupted or becomes invalid the Lassen SK8 will suspend all output of position course and speed data When a valid source of correction data is restored the Lassen SK8 will resume outputting corrected data DGPS Off When DGPS Off is selected the Lassen SK8 will not provide differential GPS solutions even if a valid source of correction data is supplied In this mode the receiver will only supply standard GPS data DGPS Automatic DGPS Automatic is the default operating mode for the Lassen SK8 In this mode the Lassen SK8 will provide differential GPS solutions when valid correction data is available If a set of differentially correctable satellites cannot be found whic
126. en SK8 software interface the start up characteristics for the interface protocols a description of the receiver operating modes and a brief discussion of the interface protocols 3 1 Start up ACE GPS is a complete 8 channel parallel tracking GPS receiver designed to operate with the L1 frequency standard position service Coarse Acquisition code Using two highly integrated Trimble custom integrated circuits the receiver is designed in a modular format especially suited for embedded applications When connected to an external GPS antenna the receiver contains all the circuitry necessary to automatically acquire GPS satellite signals track up to 8 GPS satellites and compute location speed heading and time The receiver will automatically begin to search for and track GPS satellite signals at power up The performance 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 Refer to Chapter 4 for additional information The first time the receiver is powered up it is searching for satellites from a cold start no almanac While the receiver will begin to compute position solutions within the first two minutes it actually takes the receiver about 15 minutes to download a complete almanac This initialization process should not be interrupted With a complete almanac and back up power the time to first fix can typically be shortened
127. enabled or encrypted The message may be blank A 17 29 Report Packet 0x4A This 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 then the receiver sends this packet each time a fix is computed Lassen SK8 Embedded GPS Module A 33 Trimble Standard Interface Protocol A 17 30 Main 0x4A Report Packet Type The data format is shown below Table A 33 Report Packet 0x4A Data Formats Item Type Units Latitude SINGLE radians for north for south Longitude SINGLE radians for east for west Altitude SINGLE meters HAE or MSL Clock Bias SINGLE meters Time of Fix SINGLE seconds GPS or UTZ The LLA conversion is done according to the datum selected using Packet Ox8E 15 The default is WGS 84 Altitude is referred to the datum 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 known position Packet 0x84 provides a double precision version of this information Ww Caution When converting from radians to degrees significant and readily visible errors will be introduced by use of an insufficiently preci
128. er source Lassen SK8 Embedded GPS Module Starter Kit AC DC Power Converter Connect the output cable of the converter to the 3 pin power connector on the interface unit Using the appropriate 3 prong AC power cable not provided connect the converter to an AC wall socket 110 VAC or 220 VAC The AC power cable is not provided in the Starter Kit Power Converter Electrical Figure 1 10 Interconnect Diagram 1 6 Running the TSIP Interface Program The Starter Kit includes a disk containing TSIP interface programs which run on a PC DOS platform These programs aid system integrators in monitoring the receiver module s performance and in developing the software interface for the GPS module The TSIP programs are described in detail in Appendix B TSIP User s Guide 1 Connect one end of the serial interface cable to Port 1 of the Starter Kit interface unit Connect the other end of the cable to COMI or COM 2 of your PC 2 Turn on the DC power source or plug in the AC DC converter 3 Turn on the PC 4 Insert the GPS Tool Kit disk in the disk drive 5 to the directory where you wish to establish the GPS tool kit sub directory In most cases this will be the root directory on the C drive Note For detailed installation guidelines read the install text file ANNEADME TXT The toolkit disk contains a self extracting zip file that installs the program onto your DOS computer Lassen SK8 Embedded GPS M
129. es the time required for initialization This packet is ignored if the receiver is already calculating positions The data format is shown below To initialize with latitude longitude altitude use Command Packet 0x2B Table A 16 Command Packet 0x23 Data Format Byte Item Type Units 0 3 X Single Meters 4 7 Y Single Meters 8 11 Z Single Meters Command Packet 0x24 This packet requests current position fix mode of the GPS receiver This packet contains no data The GPS receiver returns Packet Ox6D Command Packet 0x25 This packet commands the GPS receiver to perform a software reset This is equivalent to cycling the power 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 will output the start up messages see Table A 5 The GPS receiver sends Packet 0x45 only on power up and reset or on request thus if Packet 0x45 appears unrequested then either the GPS receiver power was cycled or the GPS receiver was reset Command Packet 0x26 This packet requests health and status information from the GPS receiver This packet contains no data The GPS receiver returns packetOx 46 and Ox4B Command Packet 0x27 This packet requests signal levels for all satellites currently being tracked This packet contains no data The GPS receiver returns Packet 0x47 A 17 10 Command Packet 0x28 Lassen SK8 Embedded GPS Module This
130. ession The following is a sample communication session to illustrate how message qualifiers are used Query the sensor for version number for the TAIP firmware QVR The sensor responds with a message in the following form gt RVR OEM SK8 OEM STTP APP VERSION 7 52 05 23 97 38 Note The sensor identified its product name firmware version number core signal processing version number and release dates then included the checksum for the message the default for the CS Flag is TRUE Also notice that the sensor did respond to our query even though we did not send a checksum Query the sensor for its ID number gt QID lt The sensor will respond assuming factory default settings RID0000 70 Set the ID to match the number for a vehicle in your fleet and then tell the sensor to include the Vehicle ID in its responses gt SID1234 lt gt SRM ID FLAG T Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP Most Placer family sensors are set by default to report the PV message once every 5 seconds To schedule the PV message from vehicle 1234 to respond once every 10 seconds starting at 5 seconds after the top of the hour use the following command gt FPV00100005 ID 1234 lt The sensor will check the ID included in the message for a match with its own and then reschedule the PV message At the next scheduled time the sensor will respond with gt
131. et requests the differential position fix mode of the GPS receiver A single data byte is sent To request Report Packet 0x82 the data byte is set to contain any value between 0x5 and OxFF Lassen SK8 Embedded GPS Module A 49 Trimble Standard Interface Protocol A 17 45 Command Packet 0x65 This packet requests the status of differential corrections for a specific satellite or for all satellites for which data is available This packet contains only one byte specifying the PRN number of the desired satellite or zero to request all available The response is a Packet 0x85 for each satellite if data is available If the receiver has no valid data for any satellite no reply will be sent A 17 46 Report Packet 0x6D 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 where nsvs is the number of satellites used in the solution The GPS receiver sends this packet in response to Packet 0x24 when the receiver is doing an overdetermined fix or every 5 seconds The data format is shown in Table A 53 Table A 53 Report Packet 0x6D Data Formats Report 6D Byte Item Meaning 0 overdetermined mode BIT Value Meaning 0 2 3 2D 4 3D 0 Auto 1 Manual 1 4 SINGLE 5 8 SINGLE 9 12 SINGLE 13 16 SINGLE 16 nsvs BYTE
132. et type Therefore the ID code for OEM packets is 2 bytes long followed by the data Command Packet 0x8E 15 Set Request Datum not supported with Firmware 7 52 This packet allows the user to change the default datum from WGS 84 to one of 180 selected datums or a user entered custom datum However version 7 52 firmware will only support WGS 84 datum The datum is a set of 6 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 0x4A and 0x84 The user may wish 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 wish to use a datum which is more optimized for the local shape of the earth in that area However these optimized datum 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 See A 3 for information on saving the settings to non volatile memory Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol DX Note Version 7 52 firmware supports only WGS 84 datum To request the current datum setting the command packet contains only one data byte as shown in Table A 73 Report Packet Ox8F 15 is retur
133. f Port 2 off Port 1 in out Port 2 off Port 1 in Port 2 output End of command sentence 4 Press ENTER to complete the change Use TSIPCHAT to make additional changes NMEA 0183 Data Output The National Marine Electronics Association NMEA protocol is an industry standard data protocol which was developed for the marine industry Trimble has chosen to adhere stringently to the NMEA 0183 data specification as published by the NMEA Although the Trimble Lassen SK8 supports seven NMEA sentences that contain GPS information the standard Lassen SK8 only outputs the GGA and VTG data strings Note Contact your Trimble sales representative if you need access to all or a subset of the other five NMEA sentences Lassen SK8 Embedded GPS Module Software Interface NMEA data is output in standard ASCII sentence formats Message identifiers are used to signify what data is contained in each sentence Data fields are separated by commas within the NMEA sentence In the Lassen SK8 NMEA is an output only protocol The NMEA protocol is described in detail in Appendix E NMEA 0183 The receiver is shipped from the factory with NMEA output on Port 2 Port 2 settings can be changed using TSIPCHAT and command OxBC TSIP command 0x7A changes the NMEA output sentences and output rates The new settings are saved to BBRAM or they can be saved to non volatile memory using TSIP command Ox8E 26 3 5 Timing Applications 3 5 1
134. face Protocol Table A 38 Command Packets 0x55 and 0x35 Data Descriptions Continued Default Parameter Bit Bit Associated Byte Name Position Value Option Packet 2 timing 0 0 time type 0x42 0x43 0 GPS time Ox4A 0x83 1 UTC 0x84 0x56 Ox8F 17 Ox8F 18 1 0 reserved 2 0 reserved 3 0 reserved 4 0 reserved 5 7 0 not used 3 Auxiliary PR 0 0 off 0x5A meas 1 0 raw 0 raw PR s in 5A Ox5A 1 filtered PR s in 5A reserved 3 0 off output dBHz instead of 0x5A 0 5 1 AMU 0x47 Ox6F 4 7 reserved Note See the associated superpacket output described later this appendix Packet 8E must be used to specify which superpacket is to be output Note Automatic output of 5 A messages is supported the Lassen SK8 for backwards compatibility with older TSIP applications A 38 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 17 36 Report Packet 0x56 If East North Up ENU coordinates have been selected for the I O velocity option the receiver sends this packet under the following conditions Each time that a fix is computed In response to Packet 0x37 last known fix The data format is shown below Table A 39 Report Packet 0x56 Data Formats Item Type Units 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
135. for differential correction data The receive side of port 2 is configured to accept RTCM data 1 1 2 Starter Kit Components The Lassen SK8 is available in a developer s Starter Kit or as individual boards The Starter Kit includes all the components necessary to quickly test and integrate the module Lassen SK8 Embedded GPS Module 1 3 Starter Kit The Starter Kit components and the accessory part numbers are listed in Table 1 1 and Table 1 2 Table 1 1 Lassen SK amp 8 Starter Kit Starter Kit Part Reference Part Number Lassen SK8 Starter Kit 29467 00 8 channel Lassen SK8 receiver module Socketed 28479 99 D SK8 Interface Unit 28832 10 Magnetic Mount GPS Antenna with Cable 28367 00 AC Power Adapter 29938 Power Cable 20260 Interface Cable DB9M DB9F 19309 00 GPS Toolkit Disk 30643 01 System Designer Reference Manual 34149 01 Table 1 2 Lassen SK8 Modules Starter Kit Part Reference Part Number Standard Temperature Module 28835 10 Extended Temperature Module Table 1 3 Lassen SK 8 Optional Antennas Antenna Reference 28835 20 Part Number Hard Mount GPS Antenna 28367 70 Rooftop Antenna Kit with 75 foot cable 23726 00 Note Part numbers are subject to change Confirm part numbers with your Trimble representative when placing your order Lassen SK8 Embedded GPS Module Starter Kit 1 2 GPS Receiver Module In the Starter Kit the L
136. for output at a user specified rate starting on a given epoch from top of the hour For communication robustness the protocol optionally supports checksums on all messages It also provides the user with the option of tagging all messages with the unit s user specified identification number ID This greatly enhances the functional capability of the unit in a network environment Additionally given the printable ASCII format of all communication TAIP is ideal for use with mobile data terminals seven bit modems and portable computers Although sensors incorporating this protocol are shipped from the factory with a specific serial port setting the port characteristics are fully programmable through TAIP messages This appendix is designed for easy reference to TAIP message formats and describes all the TAIP messages defined at the time of printing Some of the defined TAIP messages are not supported by the Lassen SK8 receiver The Lassen SK8 supports the following TAIP messages Lassen SK8 supported TAIP messages include AL Altitude Up Velocity PR Protocol AM Alarm PT Port Characteristic AP Auxiliary Port Characteristic PV Position Velocity Solution CP Compact Position Solution RM Reporting Mode DC Differential Corrections RT Reset Mode DD Delta Differential Corrections ST Status ID Identification Number TM Time Date IP Initial Position VR Version Number LN Long Navigation Message Lassen SK8 Embedded GPS Module C 1 Trimble ASC
137. h meets the satellite mask settings the receiver will transition to output standard GPS solutions The Lassen SK8 automatically switches between DGPS and standard GPS based on the availability of valid correction data Lassen SK8 Embedded GPS Module Operation and Performance 4 5 4 Differential GPS Operation The Lassen SK8 is capable of accepting and decoding RTCM SC 104 data RTCM SC 104 is an industry standard protocol for differential correction data The Lassen SK8 is configured to accept RTCM SC 104 correction data over Port 2 J4 pin 7 Alternatively you can use TSIP packets 60 and 61 or the TAIP and DD messages to input differential corrections through the primary serial port J4 pin 5 4 6 Position Accuracy 4 6 1 4 6 2 GPS position accuracy is degraded by atmospheric distortion satellite and receiver clock errors and Selective Availability SA 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 SA is the most significant contributor to position error and cannot be effectively combated except with differential GPS Selective Availability SA The U S Department of Defense through a program called Selective Availability intentionally degrades GPS accuracy for civilian
138. hannel to allow the user to choose the data required for his particular application As will be discussed 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 Additional packets may be defined for particular products and these will be covered in the specifications for those products as necessary The TSIPCHAT utility part of the GPS Tool Kit is designed to exercise many of the TSIP packets The GPSSK Utility part of the GPS Took Kit is designed to exercise many of the TSIP messages 2 Automatic Output Packets The Lassen SK8 receiver module is configured to automatically output the following packets For minimal system implementations these output packets provide all of the information required for operation including time position velocity and receiver and satellite status and health Position and velocity are reported using one or more of the packets listed below depending on the selected I O options While there are other packets automatically output the following packets provide the information most commonly used No input packets are required Table 1 Automatic Output Packets Reporting Output Packet ID Description Interval 0x41 GPS time 5 seconds 0x42 0x83 0x4A position choose packet with I O options 1 second 0x84 0x43 0x56 Ox8F 17 Ox8F 18 Ox8F 20 0x43 0x56 Ox8F
139. he first two time out periods As soon as three satellites are found the receiver will compute an initial position fix The typical time to first fix is less than 2 minutes A complete system almanac is not required to achieve a first position fix However the availability and accuracy of the satellite ephemeris data and the availability of a GPS almanac can substantially shorten the time to first fix Note When installed in the interface unit the Lassen SK8 receives back up power from a lithium battery This battery enables the Lassen SK8 to always start from either a warm or hot start To force a cold start issue the 1E TSIP command Control K in the TSIP chat program on the GPS toolkit diskette in the Starter Kit Warm Start In a warm start condition the receiver has been powered down for a period of 1 6 hours but has a current almanac and an initial position and time stored in memory When connected to an external backup battery and power is applied the Lassen SK8 retains the almanac approximate position and time to aid in satellite acquisition and reduce the time to first fix When an external back up battery is not used the TSIP protocol allows the almanac an initial position and time to be uploaded to the receiver via the serial port to initiate a warm start During a warm start the Lassen SK8 identifies the satellites which are expected to be in view given the system almanac the initial position and the approxima
140. ht off of the antenna connector Do not twist the cable or attempt to pull it off at an angle as this may damage the connector To reinstall the Lassen SK8 board in the motherboard follow steps 1 4 in reverse order Note The Lassen SK8 is designed for embedded applications The digital I O lines and power lines are not designed with additional ESD protection as a stand alone module would be Use standard CMOS ESD handling precautions when removing and installing the receiver module 2 2 Lassen SK8 Embedded GPS Module Hardware Integration 2 2 Interface Connector The Lassen SK8 power and data I O functions are integrated into a single 8 pin header connector J4 The J4 connector uses 0 025 inch pins on 0 10 inch spacing refer to the mechanical outline drawing in Appendix F Table 2 1 Connector Signals ay 5 Function Description TXD 2 Port 2 transmit CMOS TTL Prime Power 5VDC 5 150 mA typical TXD 1 Port 1 transmit CMOS TTL Backup Power 3 2VDC to 5 25VDC 20 typical RXD 1 Port 1 receive CMOS TTL 1 PPS Pulse Per Second CMOS TTL RXD 2 Port 2 receive CMOS TTL GND Ground Power and Signal co By oO PM gt Pins 3 and 5 on 14 are also referred to as the primary serial port Pins and 7 are also referred to as the secondary serial port Antenna connector Fin Header Figure 2 3 Interface Connector Pin Identification 2 3 Power Requireme
141. if the user has moved more than 1 000 miles after the previous fix Note that 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 To initialize with ELEF position use Command Packet 0x23 The data format is shown inTable A 19 Table A 19 Command Packet 0x23 Data Format Byte Item Type Units 0 3 Latitude Single Radians north 4 7 Longitude Single Radians east 8 11 Altitude Single Meters A 17 13 Command Packet 0x2D This packet requests the calculated offset of the GPS receiver master oscillator This packet contains no data The GPS receiver returns Packet Ox4D This packet is used mainly for service The permissible oscillator offset varies with the particular GPS receiver unit A 17 14 Command Packet 0x2E This packet provides the approximate GPS time of week and the week number to the GPS receiver The GPS receiver returns Packet Ox4E 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 This packet is usually not required when the battery back up voltage is applied as the internal clock keeps time to sufficient accuracy This packet is ignored if the receiver has already calculated the time from tracking a GPS satellite Note See
142. imble Standard Interface Protocol A 17 52 Command Packet 0x7A The NMEA message mask is a 32 bit vector which 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 Hex values are OR ed together to produce the desired combined output mask For example a mask value of 0x00000005 would mean GGA and VTG messages are enabled for output the default mask and a mask value of 0x00000013F would mean all of the messages are enabled for output The Hex values used to request the NMEA interval and message mask are listed below GGA 0x00000001 GLL 0x00000002 0 00000004 GSV 0x00000008 GSA 0x00000010 ZDA 0x00000020 RMC 0x00000100 See A 3 for information on saving the settings to non volatile memory Table A 60 Command Packet 0x7A Data Formats Byte Item Type Value Meaning 0 Subcode BYTE 0 To set the NMEA interval and message mask Table A 61 Command Packet 0x7A Data Formats for Setting NMEA Interval and Message Mask Byte Item Type Value Meaning 0 Subcode BYTE 0 1 Interval BYTE The time in seconds between NMEA messages position fix rate if 0 2 5 Output UNSIGNED The NMEA bit mask for outputting mask LONG INT messages Lassen SK8 Embedded GPS Module A 55 Trimble Standard Interface Protocol A 17 53 Report Packet 0x7B Report Packet 0x7B has one form See Command Packet 0x7A for more info
143. ing options See Table A 68 A 17 61 Command Packet 0xBC TSIP Packet OxBC is used to query the port characteristics In query mode Packet OxBC is sent with a single data byte and returns Report Packet OxBC See A 3 for information on saving the settings to non volatile memory Table A 69 Command Packet 0 Port Characteristics Query Field Descriptions Item Meaning Port Number Port 1 Port 2 Current port TSIP Packet OxBC is used to set the communication parameters on Port 1 and Port 2 The table below lists the individual fields within the Packet OxBC Table A 70 Command Packet OxBC Field Descriptions Item Meaning Port to Change Port 1 Port 2 Current port None 110 baud 300 baud 600 baud 1200 baud 2400 baud 4800 baud 9600 baud 19200 baud 38400 baud Input Baud Rate OONDOaABRWN O Output Baud Rate As above Data Bits 7 bits 8 bits Parity None Odd Even Stop Bits 1 bit 2 bits A 60 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol Table A 70 Command Packet 0xBC Field Descriptions Continued Item Meaning Flow Control OR of bits 0 none 12 RTS CTS 2 transmit Xon Xoff 4 transmit Xany 8 receive Xon Xoff Input Protocols OR of bits 0 none 1 TAIP 2 TSIP 8 RTCM Output Protocols 0 none 1 TAIP 2 TSIP 4 NMEA Reserved A 17 62 Report Packet 0xBC TSIP Packet BC is
144. irst Fix 4 2 1 4 2 2 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 Lassen SK8 which has no memory of its previous session i e is powered on without the memory backup circuit connected to a source of DC power This is the of the box condition of the GPS module as received from the factory In a cold start condition the receiver automatically selects a set of eight satellites and dedicates an individual tracking channel to each satellite to search the Doppler range frequency for each satellite in the set If none of the eight selected satellites is acquired after a pre determined period of time time out the receiver will select a new search set of eight satellites and will repeat the process until the first satellite is acquired As satellites are acquired the receiver automatically collects ephemeris and almanac data The Lassen SK8 uses the knowledge 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 t
145. iver in this packet should be accurate to a few kilometers For high accuracy time transfer position should be accurate to a few meters A 17 17 Command Packet 0x35 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 The I O options their default states and the byte values for all possible states are shown below These option states are held in battery backed memory and can be set into non volatile RAM EEPROM with the 0x8E 26 command The GPS receiver returns Packet 0x55 See A 3 for information on saving the settings to non volatile memory These abbreviations apply to the following table ALT Altitude ECEF Earth centered Earth fixed XYZ Cartesian coordinates LLA latitude longitude altitude HAE height above ellipsoid WGS 84 Earth model ellipsoid MSL geoid mean sea level and UTC coordinated universal time A 24 Lassen SK8 Embedded GPS Module Table A 21 Parameter Name Bit Position Default Bit Value Trimble Standard Interface Protocol Option Command Packets 0x35 and 0x55 Data Descriptions Associated Packet position 0 LSB 1 XYZ ECEF Output 0 off 1 on 0x42 or 0x83 LLA Output 0 off 1 Ox4A or 0x84 LL
146. l Drawings F 10 Lassen SK8 Embedded GPS Module Glossary This section defines technical terms and abbreviations used in this manual It includes terms from the field of GPS technology 2 D 2 D GPS mode 2 dRMS 3 D 3 D GPS mode almanac ASCII asynchronous communication auto GPS mode azimuth angle Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed 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 Twice the distance root mean squared The error distance within which 95 of the position solutions will fall Three Dimensional A 3 D position is defined as latitude longitude and altitude 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 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 for all the satellites in the system American Standard Code for Information Interchange A standard set of 128 characters symbols and
147. l GPS Reference Station to the GPS data collected by the RPU unit on board the vehicle differential processing GPS measurements can be differenced between receivers satellites and epochs Although many combinations are possible the present convention for differential processing of GPS phase measurements is to take differences between receivers single difference then between satellites double difference then between measurement epochs triple difference differential relative Determination of relative coordinates of two or more receivers which are positioning simultaneously tracking the same satellites Static differential GPS involves determining baseline vectors between pairs of receivers Also see differential GPS dilution of precision 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 three coordinates HDOP Horizontal two horizontal coordinates VDOP Vertical height only TDOP Time clock offset only DOP see dilution of precision Doppler aiding The use of Doppler carrier phase measurements to smooth code phase
148. lable on the GPSSK main menu will explain menu operation and the menu hierarchy Lassen SK8 Embedded GPS Module GPSSK User s Guide TAIP D 5 Connecting the GPS Sensor Consult the Installation and Operator s Manual for information on installation power requirements and cables specific to your Placer family sensor Connect the serial port of the sensor to the computer s COMI or COMZ port The default serial port settings for GPSSK are 4800 baud 8 data bits 1 stop bit no parity These default settings match the default settings for most Placer family sensors Consult the Installation and Operator s Manual for the actual default settings and type of serial port on your sensor If the sensor is connected to COMO start GPSSK by entering the command GPSSK 2 DX Note A null modem may be required when connecting the sensor to a personal computer The serial port on your computer is a DTE port data terminal equipment designed to connect to a DCE port data communications equipment If your sensor s serial port is DTE you must use a null modem adapter Lassen SK8 Embedded GPS Module D 3 GPSSK User s Guide TAIP D 4 Lassen SK8 Embedded GPS Module E 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 informatio
149. lf test See Note 1 0x26 receiver health 0x46 0x4B 0x27 signal levels 0x47 0x28 GPS system message 0x48 Ox2A altitude for 2 D mode Ox4A 0x2B initial position Lat Lon Alt 0x2D oscillator offset 0x4D 0x2E set GPS time Ox4E 0x31 accurate initial position XYZ Cartesian ECEF 0 32 accurate initial position 0 35 options 0 55 0 37 status and values of last position and velocity 0x57 0x38 load or request satellite system data 0x58 0x39 satellite disable 0x59 Ox3A last raw measurement 0x5A see Note 2 0x3C tracking status 0x5C see Note 2 0x60 type 1 differential correction 0x61 set differential correction 0x62 request differential GPS position fix mode 0x82 0x65 differential correction status 0x85 see Note 2 0x6E Synchronized Measurement output control Ox6E 0x70 filter configuration 0x70 Ox7A set request NMEA output configuration 0x7B 0xBB set receiver configuration OxBB OxBC Set port configuration OxBB Lassen SK8 Embedded GPS Module A 13 Trimble Standard Interface Protocol X A 14 Table A 12 User Selected Command Packet Options Continued Input ID Packet Description Output ID Ox8E 15 set request current datum values Ox8F 15 Ox8E 20 last fix with extra information fixed point Ox8F 20 Note 1 Output is determined by Packet 0x35 settings See Table A 5 to determine which messages are output at power up Note 2 No response sent if data is not available
150. lower better PDOP the signals from low elevation satellites are poorer quality since they suffer greater tropospheric and ionospheric distortion than the signals from higher elevation satellites These signals travel further through the ionospheric and tropospheric layers In addition low elevation satellites can contribute to frequent constellation switches since the signals from these satellites are more easily obscured by buildings and terrain Constellation switches can cause noticeable jumps in the position output Since worldwide GPS satellite coverage is generally excellent it is not usually necessary to use satellites below a 5 elevation to improve GPS coverage time In some applications like urban environments a higher mask may be warranted to minimize the frequency of constellation switches and the impact of reflected signals SNR Mask Although the Lassen SK8 is capable of tracking signals with SNRs as low as 0 the default SNR mask is set to 3 to eliminate poor quality signals from the fix computation and minimize constellation switching Low SNR values may result from Low Elevation Satellites Partially Obscured Signals e g Dense Foliage Multi Reflected Signals Multi Path The distortion of signals and the frequent constellation switches associated with low elevation satellites were discussed above In mobile applications the attenuation of signals by foliage is typically a temporary condition Since the Lassen S
151. m Type Value Meaning 0 Subcode BYTE 1 Synchronized measurement Parameters Lassen SK8 Embedded GPS Module A 51 Trimble Standard Interface Protocol A 17 48 Report Packet Ox6E Synchronized Measurements Report Packet Ox6E reports the setting of Synchronized Measurement parameters The values are shown in Table A 56 See Command Packet Ox6E for more information Table A 56 Set Synchronized Measurement Parameters Item Meaning Subcode Synchronized Measurement Parameters Enable Outputs are disabled Outputs are enabled Output Output interval in seconds Interval synchronized to the GPS time of week A 17 49 Report Packet 0x6F Subcode 1 Table A 57 Synchronized Measurements Report Meaning 0 Subcode BYTE 1 Synchronized Measurements Begin Preamble 1 Preamble BYTE 2 Begin preamble 2 3 Length INTEGER Number of bytes preamble to postamble inclusive 4 11 Receive Time DOUBLE msecs Time of GPS week 12 19 Clock Offset DOUBLE msecs Receiver clock offset 20 of SVs BYTE Number of satellites Begin Packet Data bytes number of SVs times 27 bytes per SV 21 48 SV PRN BYTE 1 32 Pseudorandom number of satellite 22 49 FLAGS1 BYTE Table 0 2 Flag values show Synchronized Measurement status of satellite 23 50 FLAGS2 BYTE 0 Reserved set to zero 24 51 Elevation Angle BYTE degrees Satellite elevation angle 25 26 Azimuth
152. mber of SVs in packet 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 51 Table A 51 Report Packet 0x60 Data Formats for Health and Power Item Units SV PRN scale factor Range correction RTCM 104 Range rate correction RTCM 104 IODE A 48 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 17 43 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 unless the version 2 flag is set The format for this packet is shown in Table A 52 Table A 52 Command Packet 0x61 Data Formats Byte Item Type 0 1 Modified Z count WORD 2 set MSB for version 2 Bit 7 1 BYTE Bit 0 6 number of SVs The next 3 bytes are repeated as a group for each satellite 3 N 3 SV PRN amp scale factor BYTE 4 N 3 Delta range correction WORD RTCM 104 The units and scale factors are as defined by Packet 0x60 Delta range correction rates are not entered A 17 44 Command Packet 0x62 This pack
153. mble SPS ALIENI BN 2836 Qd SFR NG 6 12 99 SUSAN 9 WUAHIS SaS avo i 72S 7 0981 Oud 353130 T Bual NOLdROSsIA SNOISIA3H Vay AQ ANS 3IOLD3NNOO a g g z 19 1 GPS Miniture Antenna Figure F 3 Lassen SK8 Embedded GPS Module F 8 Specifications and Mechanical Drawings 40 1 zs 3NON aes Y 04 19 80 ON 9Md ON m AINSSI YNNALNV ONIMVHO 31725 LON 00 HSINIA THY0HH 6 7 9 SYNOHL 9 Syn ee STAO Ydd wwg WWG wwe E iaysvo goo V 62 t c 4 61 Q SPL uuc A WO 079 SSONDY 70 901 LOD 96 6 NOLINGOYd 404 3SY3 194 V 3 08ddv iN NOlLdl0S30 SNOISIASY 421534109 NO LWA amp 3A1S AHL NOdII 3AISAHOV 0G d9 OL an GOV B Se OL ANNE l d HI CX I VI SALON Bulkhead Antenna Figure F 4 F 9 Lassen SK8 Embedded GPS Module Specifications and Mechanica
154. message will be ignored This process is followed even when the ID_Flag is turned off refer to the message RM Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP C 13 Initial Position Data String Format AAABBBBCCCCC Table C 13 Initial Position Data String Descriptions Item of Char UNITS Format Initial Latitude 3 Deg AAA Initial Longitude 4 Deg BBBB Initial Altitude 5 10 Meters CCCCC Total 12 This is a very coarse initial position that the user can provide to aid the sensor in obtaining its first fix This is specially useful with sensors that do not have non volatile Battery Backed up memory In such cases every time the unit is powered up it goes through a complete cold start and it has absolutely no knowledge of where it is Providing this message improves performance by decreasing the time to first fix and enhances the accuracy of the initial two dimensional navigation solutions by providing a reference altitude In case of units with non volatile memory sending this message is only helpful if the unit has moved more than 1 000 miles since its previous fix In either case the sensor can initialize itself appropriately without any data from the user It merely requires more time DX Note For all the above values the first character specifies the sign Example The following message will set the initial position to 37 North 122
155. n NMEA 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 Lassen SK8 receiver 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 Lassen SK8 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 E 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 E 1 NMEA 0183 Characteristics Signal Characteristic NMEA Standard Baud Rate 4800 Data Bits 8 d7 0 Parity None Disabled Stop Bits 1 Lassen SK8 Embedded GPS Module
156. n UTM Universal Transverse Mercator format The UTM coordinate system is typically used for U S and international topographical maps The UTM coordinate system lays out a world wide grid consisting of the following 60 North South zones 6 increments extending eastward from the International Date Line 10 East West zones divided in 8 increments extending above and below the Equator Coordinates within these boundaries cover all surface locations from 80 South to 84 North and encircle the earth Locations are indicated by offset from the equator and in the zones east of the International Date Line These offsets are known as Northing and Easting and are expressed in meters UTM is not usable in polar regions Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol Table A 80 Report Packet 8F 18 Field Descriptions Description Type Subcode Byte Gridzone Designation Char Gridzone Integer Double Double Double Double Single Northing Meters Easting Meters Altitude Clock Bias Time of Fix Meters Meters Seconds A 18 8 Report Packet Ox8F 19 This packet reports whether the UTM output packets is enabled If bit 4 byte 0 in packet 0x35 0x55 is single precision 0x17 will be output Table A 81 Command Packet 0x8F 19 Field Descriptions Description Value Subcode 0x19 UTM Status E Enable D Disable A 18 9 Report P
157. n a byte of data which carry the actual information Refers to a mathematical model of the earth Many local datums model the earth for a small region e g Tokyo datum Alaska NAD 27 North America Others WGS 84 for example 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 Navigation see differential GPS Lassen SK8 Embedded GPS Module Glossary 2 D Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed DGPS reference station A device that tracks all GPS satellites in view periodically performs inter channel calibrations and calculates and transmits differential corrections differential capable A term used to describe a GPS receiver that is capable of receiving and applying differential GPS corrections differential GPS A procedure of correcting GPS solutions to achieve improved position accuracy Differential GPS provides 2 to 5 meter position accuracy Differential accuracy is obtained by applying corrections determined by the stationary Differentia
158. n differential position solutions Mode 3 Auto GPD Differential currently on The receiver is receiving differential correction data for all satellites in a constellation which meets all other masks and is doing differential position solutions A 56 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 17 55 Report Packet 0x83 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 position option is selected the receiver sends this packet each time a fix is computed The data format is shown in Table A 63 Table A 63 Report Packet 0x83 Data Formats Type Units 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 Packet 42 provides a single precision version of this information A 17 56 Report Packet 0x84 This packet provides current GPS position fix in LLA coordinates If the I O position option is set to LLA and the double position option is selected the receiver sends this packet each time a fix is computed The data format is shown in Table A 64 Table A 64 Report Packet 0x84 Data Formats Item Type Units latitude DOUBLE radians for north for south longitude DOUBLE radians for east for west altitude DOUBLE meters clock bias DOUBLE me
159. n the message C 23 2 The Response to Query or Scheduled Report The response R qualifier carry various types of data between the unit and the user equipment The format is gt RAA B ID CCCC DD lt where AA is the two character message identifier and B specifies the data string within the message For the format of B please refer to the message definitions in the previous section Messages supported by the response qualifier are AL AM AP CP ID IP LN PT PV RM ST TM VR and X1 Lassen SK8 Embedded GPS Module C 27 Trimble ASCII Interface Protocol TAIP C 23 3 C 23 4 C 28 The Set Qualifier The set S qualifier enables the user equipment to initialize set up various types of data in the GPS unit The format is gt SAA B ID CCCC DD lt where AA is the two character message identifier and B specifies the data string within the message For the format of B please refer to the message definitions in the previous section Note that all the messages have very specific formats and are length dependent Messages normally supported by the set qualifier are AL AP CP DC DD ID IP LN PT PV RM and TM the Placer GPS DR does not support the set qualifier for the AP message The set qualifier may be used with the AL CP LN or PV message to set more precise initial position data into the GPS sensor than can be set with the IP message Sample Communication S
160. nd Land 0xBB Elevation mask 10 59 5e OxBB Signal mask 6 0 4 0 2 0 0xBB DOP mask 6 0 12 0 12 0 OxBB DOP switch NA 8 0 5 0 0xBB DGPS correction age 10 Seconds N A 30 Seconds The default values in Table A 15 allow the receiver to operate well under the most varied and demanding conditions A user may choose to change the default parameters if the receiver is only required to perform in a specific or limited environment The user should be warned that when the receiver is exposed to operating conditions which are different from the conditions described by the user setup then the performance may be degraded Initially the user must consider the environment in which the receiver is expected to operate There is a trade off between how frequently a position fix is output versus the absolute accuracy of the fix The user must decide which takes priority and then make the appropriate selections This becomes increasingly important when frequent satellite blockages are expected as in downtown urban canyon environments and heavily foliated areas Following is a description of the key fields in Packet OxBB Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 15 1 Packet OxBB Set Fix Mode Packet OxBB is used to choose the appropriate position fix mode for your application 2 D 3 D or AUTO The default mode is AUTO 2 D 3 D where the receiver first attempts to obtain a 3 D solution with a PDOP below both the DO
161. 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 DLE bytes Multiple byte numbers integer float and double follow the ANSI IEEE Std 754 IEEE Standard for binary Floating Point Arithmetic 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 Specifically INTEGER 16 bit unsigned number sent in two s complement format SINGLE Float or 4 byte REAL has a precision of 24 significant bits roughly 6 5 digits DOUBLE 8 byte REAL has a precision of 52 significant bits It is a little better than 15 digits Lassen SK8 Embedded GPS Module A 19 Trimble Standard Interface Protocol A 17 Packet Descriptions A 20 A 17 1 A 17 2 A 17 3 A 17 4 Command Packet 0x1D 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 To clear the oscillator offset one data byte is sent the ASCII letter C 0x43 To set the oscillator offset four data bytes are sent the oscillator offset in Hertz as a Single real value Command Packet 0x1E This packet commands the GPS receiver to clear all battery back up data and to perform a software reset This packet contains one data byte Caution All almanac ephemeris
162. ned Table A 72 Command Packet 0 8 15 Field Descriptions Byte Type Value 0 Superpacket ID 0x15 To change to one of the internally held datum the packet must contain exactly 2 bytes representing the integer value of the index of the datum desired Table A 73 Command Packet 0x8E 15 Datum Index Field Descriptions Type Value Superpacket ID 0x15 INTEGER Datum index Note request the current datum send Packet 8E 15 with no data bytes Alternatively the unit will accept a 42 byte input packet containing 6 double precision floating point value representing the ellipse The first 3 are DX DY and DZ which represent an offset in meters from the 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 squared of the ellipse and is dimensionless Ww 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 74 Command Packet 0x8E 15 Eccentricity of the Ellipse Parameter Field Descriptions Type Superpacket ID DOUBLE DOUBLE DOUBLE Lassen SK8 Embedded GPS Module A 63 Trimble Standard Interface Protocol A 64 A 18 2 A 18 3 Table A 74 Command Packet 0x8E 15 Eccentricity of the Ellipse Parameter Field Descriptions 25 32 DOUBLE A axis m 33 40 DOUBLE Eccen
163. ng gt Start of Message Delimiter R Response Qualifier PV PV message Identifier 15714 GPS Time of Day 3739438 Latitude 12203846 Longitude 015 Speed 126 Heading 1 Source of Data 2 Age of Data 10 1234 Vehicle ID STF Checksum End of Message Delimiter Note Refer to the discussion of the PV message data stri message is interpreted ng for more detail on how this Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP C 3 Time and Distance Reporting The D message qualifier allows you to specify a minimum distance traveled as well as a minimum and maximum time interval for the next report Units that are stationed at a fixed location can be programmed to report only when the unit moves off station or after a certain elapsed time since last report but no more often than the specified minimum time interval The message format used with the D qualifier is shown below gt DAABBBBCCCCEEEEFFFFE ID GGGG HH lt Table C 4 Time and Distance Reporting Message Format Qualifiers ID Meaning gt start of message delimiter D the Distance message qualifier AA message to report i e PV means Position Velocity message BBBB minimum time seconds interval between reports Tinterval CCCC report epoch number of seconds from top of the hour EEEE delta distance meters from last reported distance FFFF maximum time
164. nning on Page 20 A 1 Interface Scope The Trimble Standard Interface Protocol is used in Trimble 6 channel and 8 channel receiver designs The protocol was originally created for the Trimble Advanced Navigation Sensor TANS and is colloquially known as the TANS protocol even though the protocol applies to many other devices The Lassen SK8 has two independently configurable serial I O communication ports Port is a bi directional control and data port utilizing a Trimble Standard Interface Protocol TSIP or Trimble ASCII Interface Protocol TAIP Port 2 is a bi directional port used to receive differential GPS DGPS corrections in the industry standard RTCMSC 104 format and for output of industry standard ASCII NMEA sentences Port 1 can also be configured to TAIP I O using the TSIP command The dual data I O port characteristics and other options are user programmable and stored in non volatile memory The TSIP protocol is based on the transmission of packets of information between the user equipment and the unit Each packet includes an identification code 1 byte representing 2 hexadecimal digits that identifies the meaning and format of the data that follows Each packet begins and ends with control characters Lassen SK8 Embedded GPS Module A 1 Trimble Standard Interface Protocol This document describes in detail the format of the transmitted data the packet identification codes and all available information over the output c
165. ns from RTCM 104 record types 1 and 9 The values are numerical values written out in hex format thus for each byte of data there is a two digit hex number C 10 Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP The format of the data string is as follows AAAABBCC DDEEEEFFGG Table C 9 RTCM 104 Record Types 1 and 9 Data String Descriptions Item of Char Type UNITS Format Modified Z count 4 WORD 6 sec AAAA Station health 2 BYTE n a BB Number of SVs 2 BYTE n a CC The next 5 bytes 10 characters are repeated for each SV SV PRN amp health UDRE 2 BYTE n a DD Range Correction 4 WORD RTCM 104 EEEE Range rate 2 BYTE RTCM 104 FF correction IODE 2 BYTE n a GG The units and scale factors are as defined by RTCM 104 version 1 The SV PRN and health contains the SV PRN in the lower 5 bits and the health UDRE scale factor in the upper 3 bits Range corrections are scaled by 0 02 meters times 2 raised to the health power Range rate corrections are scaled by 0 002 meters per second times 2 raised to the health power Note The and DD TAIP messages described herein apply only to differential ready sensors and are provided to enclose differential corrections within the TAIP format Use of DC and DD messages to input corrections requires only one communications channel Use of the auxiliary port to input RTCM 104 cor
166. nt The Lassen SK8 receiver module requires 5 volts DC 5 at 150 mA typically excluding the antenna For power on surge design considerations the prime power should be able to source up to a maximum load of 200 mA The on board capacitance on prime power is 10 uF An important design consideration for power is the receiver module s internal clock frequency at 12 504 MHz 3 KHz Interference spurs on prime power in this narrow frequency band should be kept to less than 1mV Lassen SK8 Embedded GPS Module 2 3 Hardware Integration gt lt The receiver does not require any special power up or down sequencing The receiver power is supplied through pin 2 of the I O connector Refer to Table 2 2 for the 5 VDC power specifications The Lassen SK8 module provides an input for battery back up BBU power to keep the module s RAM memory alive and to power the real time clock when the receiver s prime power is turned off RAM memory is used to store the GPS almanac ephemeris and last position User configuration data including port parameters and receiver processing options are stored in non volatile EEROM which does not require back up power By using battery back up time to first fix is reduced to 20 seconds typical Though not required providing BBU power can reduce power on time A 3 6 volt lithium battery used for back up power can last up to five years Note 3 2V is the minimum allowable voltage When the power output drops belo
167. nt on the quality and age of the differential corrections and the proximity of the mobile receiver to the reference site Lassen SK8 Embedded GPS Module 4 7 Operation and Performance 4 7 Coordinate Systems 4 8 4 7 1 Once the Lassen SK8 achieves its first fix it is ready to commence output of position velocity and time information This information is output over serial communication channel in either the TSIP TAIP or NMEA protocol as determined by the settings of the receiver These protocols are defined in the following Appendices TSIP Appendix A TAIP Appendix C e NMEA Appendix E To change from one protocol to another please see Configuring your Receiver in Appendix A TSIP Coordinate Systems TSIP has the widest choice of coordinate systems The output format is chosen by TSIP command 0x35 The output formats include the following LLA position Latitude longitude altitude LLA according to the WGS ellipsoid or one of over a hundred other datums See Appendix A Table A 86 for a list of available datums Altitude can be chosen to be height above ellipsoid HAB or height above mean sea level MSL ENU velocity ENU velocity is the velocity in East North and Up coordinates These coordinates are easily converted to speed and heading ECEF position and velocity ECFF position and velocity is Earth Centered Earth Fixed frame is a Cartesian coordinate frame with its center at the
168. nterface Protocol DX Note Auto report requires that superpacket output is enabled Refer to Command Packet 35 A 18 4 Command Packet Ox8E 26 The Ox8E 26 command is issued with no data to cause the current settings to be saved to non volatile memory See A 3 for information on saving the settings to non volatile memory The Ox8F 26 report is generated after the values have been saved Table A 77 Command Packet Ox8E 26 Definitions Byte Item Type Value Meaning 0 Subcode BYTE 0x26 Save Settings A 18 5 Report Packet Ox8F 15 Current Datum Values not supported with Firmware 7 52 This packet contains 43 data bytes with the values for the datum currently in use and is sent in response to Packet Ox8E 15 However version 7 52 firmware will only support WGS 84 datum If a built in datum is being used both the datum index and the 5 double precision values for that index will be returned If the receiver is operating on a custom user entered datum the datum index will be set to 1 and the 5 values will be displayed These 5 values describe an ellipsoid to convert ECEF XYZ coordinate system into LLA Table A 78 Report Packet 0x8F 15 Field Descriptions for Converting Ellipsoid ECFF XYZ to Coordinate System LLA Type Value BYTE Id for this sub packet always 0x15 INTEGER Datum Index 1 for custom DOUBLE DX DOUBLE DY DOUBLE DZ DOUBLE A axis DOUBLE Eccentricity Squared DX Note A complet
169. nual Lassen SK8 Embedded GPS Module B 1 TSIP User s Guide TSIPCHAT Starting TSIPCHAT Report Packets B 2 TSIPCHAT is a program that provides full visibility into the TSIP interface Source code is provided The source code dual windows requires a BORLAND C compiler To start the program type TSIPCHAT CI or TSIPCHAT C2 for COMI or COM2 the command line is TSIPCHAT Cx where x is 1 for PC serial port COMI or 2 for 2 This choice can be changed while TSIPCHAT is running using the CTRL I command As TSIPCHAT starts it displays a list of commands in the upper half of the console screen command window and a running account of automatic unrequested reports in the bottom half of the screen auto window It also sets the serial port to the default settings of 9600 baud 8 Odd 1 If the receiver is alive and outputting positions position reports scroll immediately in the auto window If the auto window is empty type v to test if the receiver is connected properly to the computer If the serial port is properly connected the receiver responds within a second with the receiver software version numbers otherwise waiting for reply remains on the screen When a TSIP report packet is issued by the receiver it is received by TSIPCHAT translated into a printable form and put on the screen If the report packet has been specifically requested by a command it is put in the command upper window otherwise i
170. ocol TAIP AABBCCDDDEEFFGGGGHHIJJKLLLLL Table C 25 TM Time Data Data String Descriptions Item of Char UNITS Format Value Hours 2 Hour AA Minutes 2 Min BB Seconds 5 Sec CC DDD Date Day 2 Day EE Date Month 2 Month FF Date Year 4 Year GGGG GPS UTC Time 2 Sec HH Offset Current Fix Source 1 n a 0 2D GPS 1 3D GPS 2 2D DGPS 3 30 DGPS 6 DR 8 Degraded DR 9 Unknown Number of Usable 2 n a JJ SVs GPS UTC Offset 1 n a K 1 Valid Flag 0 Invalid Reserved 5 n a LLLLL Total 28 This message outputs the time and date as computed by the GPS sensor The time is most accurate when the unit is doing fixes It is less accurate but still usable when the unit is not doing fixes but the Number of Usable SVs is one or more Note GPS UTC Time Offset is the difference between GPS and UTC time standards in seconds The UTC time of Day is only valid if the GPS UTC Offset Valid Flag is indicating valid The TM message is supported under the Set qualifier which allows you to download time to a GPS receiver that does not have a real time clock Lassen SK8 Embedded GPS Module C 25 Trimble ASCII Interface Protocol TAIP The format for using the S qualifier with the TM message is gt STMAABBCCDDDEEFFFFGGGGGGGGGGG lt Where gt Start of message delimiter Set mes
171. odule 1 11 Starter Kit 6 At the DOS prompt type A INSTALL The executable program creates a sub directory called TOOLKIT and installs the tool kit files ga Type the appropriate path name to execute the TSIPCHAT program e g C TOOLKIT TSIPCHAT TSIPCHAT provides full access to the TSIP protocol It converts binary TSIP packets into printable ASCII characters and vice versa When TSIPCHAT is initiated it configures the PC serial port to the default TSIP settings 9600 baud 8 Odd 1 8 After the TSIPCHAT title screen appears press and the primary TSIPCHAT screen shown in Figure 1 11 is displayed 9 test the connection press V This message requests the firmware version numbers from the GPS module If connected and operating properly the module should respond with a software version report within one second This report will be displayed in the command window When a GPS antenna is connected to a receiver and has achieved a position fix the transmitted position reports scroll through the report window see Figure 1 11 These reports include position velocity and other GPS information A receiver health report is sent every few seconds even when no satellites are being tracked 57 PM tsipchat 5 13 96 troke Command List Key Pkt ID Description xlE clear battery A 0x20 altitude f 0x t recy SV data S N 5 i lt raw meas meris info status L info mode b CC UB peration et receiver
172. of bytes of data to be loaded 4 to n 3 data n Bytes Ww Caution Proper structure of satellite data is critical to SVeeSix 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 Note Ephemeris not loaded into the receiver in Version 7 52 Lassen SK8 Embedded GPS Module A 27 Trimble Standard Interface Protocol A 17 20 Command Packet 0x39 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 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 0x59 for operation modes 3 and 6 only It should be noted that when viewing the satellite disables list the satellites are not numbered but are in numerical order The disabled satellites are signified by a 1 and enabled satellites are signified by a 0 Table A 23 Command Packet 0x39 Data Formats Item 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
173. of the apparent clock and ephemeris prediction accuracies to the ranging accuracies obtainable with a specific satellite based on historical data UTC Universal Time Coordinated Uniform atomic time system standard that is maintained by the US Naval Observatory UTC defines the local solar mean time at the Greenwich Meridian UTC offset The difference between local time and UTC Example UTC EST 5 hours Lassen SK8 Embedded GPS Module Glossary 9 Glossary Glossary 10 Lassen SK8 Embedded GPS Module Index A age of data C 10 C 19 almanac 4 11 altitude C 8 antenna 1 8 B baud rate 3 2 C cautions xxii copyrights iii D Department of Defense xix differential GPS 3 8 C 10 disclaimers iii document conventions xxii E earth centered earth fixed A 24 A 37 ECEF A 24 A 37 email xx address xx ephemeris 4 11 error codes C 23 F FaxBack xxi FTP site address xxi Lassen SK8 Embedded GPS Module G GPS xix GPS time of day C 8 GPSSK D 1 files D 1 start up D 2 H HAE A 24 A 37 height above ellipsoid A 24 A 37 Internet FTP Address xxi L latitude conversion C 6 longitude conversion C 6 N navigation processor 4 11 notes xxii organization P parity 3 2 R reader comment form xxi Index 1 Index receiver 1 6 related information email xx FaxBack xxi Internet FTP Address xxi Technical Assistance xx Worldwide Web xxi revision notice iii RTCM 104 C 10
174. om UTC time by leap seconds The keystroke z requests a time set Packet 0x21 Report Packet 0x41 The first time the request is made during execution of the program the user is prompted for the local time zone offset The user time zone offset is 0 for UTC GMT 5 for EST 4 for EDT 8 for PST 7 for PDT and positive numbers if ahead of east of GMT Allowable range is 13 hours plus or minus The accuracy of this software method is approximately 0 5 seconds To exit the program hit the EXCAPE key Lassen SK8 Embedded GPS Module TSIP User s Guide TSIPPRNT TSIPPRNT translates TSIP report packet byte streams into readable reports It uses the same report interface routines as TSIPCHAT but uses printf rather than cprintf so that output can be redirected to a file The command line for console output is TSIPPRNT tsip_filename where tsip_filename is the name of a stream of TSIP report packets collected directly from the receiver output port or from TSIPCHAT The command line for re directing output to a file is TSIPPRNT tsip_filename gt ascii filename Full source code is provided TSIPPRNT is created by compiling under any C compiler with the macro FILE INPUT defined BORLAND and PORT INPUT not defined and with the include file TSIPINCL H The following routines must be compiled TSIPPRNT C main TSIP RPT C IFC C TSIPPRNT code can be easily modified by the user to supply any ASCII output file format
175. onnection press V If the message WAITING FOR REPLY appears continuously in the command window then the GPS module is not communicating with the computer If this occurs re check the interface cable connections and verify the serial port selection If the communication failure still occurs after checking all connections and settings please call the Trimble Technical Assistance Center TAC for assistance Lassen SK8 Embedded GPS Module 1 13 Starter Kit 1 14 Lassen SK8 Embedded GPS Module 2 Hardware Integration The integration of the Lassen SK8 receiver module is discussed in two sections Hardware Integration and Software Interface This chapter Hardware Integration includes instructions for mounting the GPS module and physically connecting the module to the antenna the host processor and the power source Chapter 3 Software Interface provides guidelines for configuring the Lassen SK8 receiver module to communicate with the host processor 2 4 The Lassen SK8 Receiver Module In the Starter Kit the Lassen SK8 receiver module is installed on the interface motherboard to facilitate testing and evaluation The receiver module can be detached from the motherboard for installation into a specific device The receiver module is connected to the motherboard at four points the antenna connector the interface connector and two standoffs see Figure 2 1 Follow the steps below to remove the receiver module from the motherboard
176. ontains 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 2 seconds All data fields must be provided unless the data is temporarily unavailable Null fields may be used when data is temporarily unavailable RMC hhmmss s A llll lll a yyyyy Vyy 8a X X X X XXXXXX X x a hh Table E 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 mm yy Magnetic Variation in Degrees E East W West Checksum Mandatory for RMC 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 VTG xX x T X X M X X N X x K Table E 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 Lassen SK8 Embedded GPS Module NMEA 0183 E 4 7 ZDA Time amp Date The ZDA message contains UTC the day the month the year and the local time zone ZDA hhmm
177. orrections 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 Handover word The word in the GPS message that contains time synchronization information for the transfer from C A to P code The interface cable allows data to flow between the Placer RPU and the communication equipment One end of the cable has a single 37 pin connector the other end of this cable has an 25 pin RS 232 connectors and a set of fused red and black power leads 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 information 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 A numerical method used to track a time varying signal in the presence of noise If
178. ort Packet 0x4B Data Formats Byte Item Type Value Status Meaning 0 Machine ID BYTE 6 channel receiver 1 Status 1 BYTE see Table A 36 2 Status 2 BYTE Bit 0 Super packets supported The status codes are encoded into individual bits within the bytes The bit positions and their meanings are shown in Table A 36 Table A 36 Report Packet 0x4B Bit Positions and Descriptions Status 1 Bit Position Meaning if bit value 1 0 LSB not used not used not used The almanac stored in the receiver is not complete and current not used Lassen SK8 Embedded GPS Module A 35 Trimble Standard Interface Protocol A 17 33 Report Packet 0x4D This packet provides the current value of the receiver master oscillator offset in Hertz at carrier This packet contains one SINGLE number The receiver sends this packet in response to Packet 0x2D The permissible offset varies with the receiver unit A 17 34 Report Packet 0x4E Indicates whether the receiver accepted the time given in a Set GPS time packet the receiver sends this packet in response to Packet Ox2E This packet contains one byte Table A 37 Report Packet Ox4E Data Formats 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 from a
179. packet requests the most recent GPS system ASCII message sent with the navigation data by each satellite This packet contains no data The GPS receiver returns Packet 0x48 A 21 Trimble Standard Interface Protocol A 17 11 Command Packet 0x2A P A 22 Note This packet sets or requests the altitude parameters used for the Manual 2 D mode Reference Altitude and Altitude Flag Packet 0x4A type 2 is returned Reference Altitude is the altitude used for manual 2 D positions if the altitude flag is set Altitude is in units of HAE WGS 84 or MSL depending on the selected I O options for the position The Altitude Flag determines whether or not the Reference Altitude will be used If set it will be used If cleared altitude hold last 3 D altitude is used Note With no data bytes this packet requests the current values of these altitude parameters In this case the GPS receiver returns Packet 4A Table A 17 Packet 0x2A Set Altitude Only Description Byte Item Type Meaning 0 3 Altitude SINGLE Reference altitude for 2 D Note Sets the Altitude Flag Table A 18 Reset Altitude Flag Description Byte Item Type Value Meaning 0 Altitude Flag BYTE 0 x 00 Clear Altitude flag Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 17 12 Command Packet 0x2B This packet provides the GPS receiver with an approximate initial position in latitude and longitude coordinates WGS 84 This packet is useful
180. 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 Lassen SK8 Embedded GPS Module Glossary 2 D GPD GPS GPS antenna GPS processor GPS receiver GPS time HDOP HOW interface cable interference integrated Doppler IODE jamming Kalman filter masks Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed GPS with differential corrections applied Global Positioning System A constellation of 24 radio navigation not communication satellites which transmit signals used by GPS receivers to determine precise location position velocity and time solutions GPS signals are available world wide 24 hours a day in all weather conditions This system also includes 5 monitor ground stations 1 master control ground station and 3 upload ground stations An antenna designed to receive GPS radio navigation signals An electronic device that interprets 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 c
181. racteristics and other options are user programmable and stored in non volatile memory Warning When customizing port assignments or characteristics confirm that your changes do not effect your ability to communicate with the receiver module see Chapter 3 Software Interface Lassen SK8 Embedded GPS Module Starter Kit 1 1 1 Interface Protocols The Lassen SK8 operates using either of three protocols Trimble Standard Interface Protocol TSIP Trimble ASCII Interface Protocol TAIP and NMEA 0183 and are physically located at the following ports Port 1 TSIP or TAIP Port 2 NMEA 0183 Port 1 TSIP is a powerful binary packet protocol that allows the system designer maximum configuration control over the GPS receiver for optimum performance in any number of applications TSIP supports over 40 commands and their associated response packets for use in configuring the Lassen SK8 receiver module to meet user requirements TAIP is designed for easy integration using programmable ASCII characters in the form of 2 character message types which provide position Port 2 NMEA 0183 is an industry standard protocol common to marine applications NMEA provides direct compatibility with other NMEA capable devices such as chart plotters radars etc The Lassen SK8 receiver module supports most NMEA messages for GPS navigation NMEA messages and output rates can be user selected as required RTCM SC 104 is the GPS industry standard
182. rce code routines for the TSIPCHAT program are also provided in the Starter Kit C source can be used as a software design guide by programmers who need to communicate system integration information with the Lassen SK8 Lassen SK8 Embedded GPS Module 3 3 Software Interface 3 4 Configuring the ACE GPS receiver output protocol from TSIP to TAIP protocol TSIP command packet OxBC can be configured in accordance with the following procedure 1 Run TSIPCHAT Cx Where x Host Computer COM Port 2 Once TSIPCHAT is running a Press The following will be displayed Keystroke Command List 3 Initiate the OxBC Command Packet Refer to Packet BC in the Appendix A Trimble Standard Interface Protocol for further information a Press U b Press the SPACE BAR to cycle through the options Enter the following c Set 1 d Press Enter 4 Select the Port to be configured Do the following a Press the SPACE BAR to cycle through the options b Select Port 1 0 c Press Enter 5 Set the Receiver Port configuration Input Baud rate a Press the SPACE BAR to cycle through the options b Make a selection c Press Enter 6 Set the Receiver Port configuration Output Baud Rate a Cycle through the options by pressing the SPACE BAR b Select the Output Baud Rate c Press Enter 7 Set the Data Bits a Select the appropriate Data Bits TAIP is the default TAIP 8 b Press Enter 8 Set Parity a Select the appropriate
183. rcent of the duty cycle on the PPS line Lassen SK8 Embedded GPS Module 1 7 Starter Kit 1 3 Antenna The GPS antenna receives the GPS satellite signals and passes them to the receiver Because the GPS signals are spread spectrum signals in the 1575 MHz range and do not penetrate conductive or opaque surfaces the GPS antenna must be located outdoors with a clear view of the sky The Lassen SK8 requires an active antenna The received GPS signals are very low power approximately 140 dB at the surface of the earth Trimble s active antennas include a preamplifier that filters and amplifies the GPS signals before delivery to the receiver Trimble offers a variety of antennas for use with the Lassen SK8 The compact magnetic mount GPS antenna and integral cable supplied with the Starter Kit is ideal for portable and mobile applications A permanent bulkhead mount antenna is also available A compact pole mount rooftop antenna is available for fixed site installations Refer to Appendix F for mechanical outline drawings of the GPS antennas Figure 1 5 Magnetic Mount GPS Antenna Figure 1 6 Hard Mount GPS Antenna Lassen SK8 Embedded GPS Module Starter Kit Figure 1 7 Bullet II GPS Antenna 1 4 Power The receiver module is designed for embedded applications and requires a regulated 5 0 VDC input 4 75 to 5 25 VDC See Power Requirements in Chapter 4 for detailed specifications In the Starter Kit the motherboard inclu
184. rections assumes a separate communications channel is available for broadcast and receipt of differential corrections The TAIP software toolkit GPSSK does not support DC and DD messages Lassen SK8 Embedded GPS Module C 11 Trimble ASCII Interface Protocol TAIP C 10 DC Differential Corrections C 12 The DC message provides the sensor with differential corrections from type 1 and type 9 RTCM 104 records The numerical are written out in hex format producing a two digit hex number for each data byte Data String Format AAAABBCC DDEEEEFFGG Table C 10 Delta Differential Corrections Data String Descriptions Item of Char Type UNITS Format Modified Z count 4 WORD 6 sec AAAA Station health 2 BYTE N A BB Number of SVs 2 BYTE N A CC The next five bytes 10 characters are repeated for each SV SV PRN amp scale factor 2 BYTE n a DD Range correction 4 WORD RTCM 104 EEEE Range rate correction 2 BYTE RTCM 104 FF IODE 2 BYTE n a GG Units and scale factors are defined by RTCM 104 version 2 The SV PRN and scale factor contains the SV PRN in the lower 5 bits and the scale factor in the higher 3 bits The scale factor has only three acceptable values 0 Use with low scale factor 4 Use with high scale factor 7 Do not use Range corrections are scaled by 0 02 meters for low scale factor and 0 32 m sec for high scale factor
185. rectory D 3 GPSSK Start up At the DOS prompt in the directory containing GPSSK enter the command GPSSK When the program is finished loading into memory the GPSSK title page will be displayed The program will then wait for 10 seconds to begin normal execution you may bypass the 10 second wait by pressing any key after the title page is displayed The function key menu will be displayed on the bottom of the screen GPSSK is structured as a hierarchy of menus The function keys control access to the menus To terminate GPSSK simply back out of the menu structure by pressing F9 until GPSSK prompts you to confirm your desire to exit the program At start up GPSSK will attempt to initialize itself by querying the sensor for some basic information If you wish to abort the sensor initialization process and use GPSSK to replay stored data enter Ctrl X hold down the control key and press x If initialization has been aborted you must restart GPSSK when you wish to communicate with the sensor D 4 On line Help D 2 Once GPSSK is running on line help is available to assist in performing all the GPSSK operations Help is context sensitive and will display information regarding the current display or menu A brief overview of GPSSK is available in the main menu s help screen There are several command line options available For help with command line options run GPSSK with the HELP argument GPSSK HELP The help avai
186. rmation about the data formats To set the NMEA interval and message mask use the values shown in Table A 62 Table A 62 Report Packet 0x7B Message Mask Settings Item Type Meaning Subcode BYTE Interval BYTE The time in seconds between NMEA messages Output UNSIGNED The NMEA bit mask for outputting mask LONG INT messages A 17 54 Report Packet 0x82 This packet provides the differential position fix mode of the receiver This packet contains only one data byte to specify the mode The packet is sent in response to Packet 0x62 and whenever a satellite selection is made and the mode is Auto GPS GPD modes 2 and 3 The receiver switches automatically between modes 2 and 3 based on the availability of differential corrections for a constellation which meets all other masks If such a constellation is not available then the receiver stays in its current automatic mode 2 or 3 and does not do position solutions Valid modes are Mode 0 Manual GPS Differential off The receiver does position solutions without differential corrections even if the differential corrections are available Mode 1 Manual GPD Differential on The receiver only does position solutions if valid differential correction data are available Mode 2 Auto GPS Differential currently off The receiver is not receiving differential correction data for all satellites in constellation which meets all other masks and is doing no
187. rotocol TAIP C 23 Communication Using TAIP Communication with the unit takes place in four different ways Message qualifiers are used to differentiate between these C 23 1 Query for Single Sentence The query Q message qualifier is used to query the GPS sensor to respond immediately with a specific message The format is gt QAA ID BBBB CC lt where AA is the requested message identifier Messages supported by this qualifier are AL AM AP CP ID IP LN PT PV RM ST TM VR and X1 Scheduled reporting frequency interval The scheduled reporting frequency interval F message qualifier is used to tell the unit how often and when to report a specific message The format is FAABBBBCCCC ID DDDD FF lt where sending this sentence tells the unit to report message specified by the two digit identifier AA at the time interval of BBBB seconds with time epoch at CCCC seconds from top of the hour Specifying time interval of 0000 stops scheduled reporting of the message The default is 0000 time interval for all messages except PV The output frequency for PV at cold start is set at once every five seconds zero seconds from top of the hour Messages supported by this qualifier are AL AM AP CP ID IP LN PT PV RM ST TM VR and X1 DX Note The data specified by this qualifier is the timing of the message output and may be different from the time tag of the data i
188. s Item of Char UNITS Format Value Baud Rate 4 n a AAAA 9600 4800 2400 1200 or 0300 of data bits 1 n a B 7 or 8 of stop bits 1 n a C 1 or 2 Parity 1 n a D N None O Odd E Even Total 10 including commas This message defines the characteristics for the primary TAIP port Most TAIP using sensors use the following default port characteristics consult the Installation and Operator s Manual 4800 baud 8 data bits 1 stop bit No parity Note The characteristics set by this message will be stored in the sensor s memory The Lassen SK8 family of sensors do not include an internal battery but provide a battery back up input line that may be used to retain memory when main power is removed Note If you do not use battery back up all port characteristics will reset to the default after power is removed Note The PT command uses commas between data fields C 18 Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP C 17 PV Position Velocity Solution Data String Format AAAAABBBCCCCCDDDDEEEEEFFFGGGHI Table C 17 Position Velocity Solution Data String Descriptions Item of Char UNITS Format Value GPS Time of day 5 Sec AAAAA Latitude 8 Deg BBB CCC CC Longitude 9 Deg DDDD E EEEE Speed 3 MPH FFF Heading 3 Deg GGG Source 1 n a H 0 2 2D GPS 1 3D GP
189. s Guide Serial Port Parameters default at start up is 9600 baud 8 odd 1 The serial port parameters the computer can be adjusted by typing I The program will prompt for new serial port parameters TCHAT TCHAT is a simplified version of TSIPCHAT TCHAT C provides a good basis for GPS software development The command line syntax is TCHAT c port number f optional file name where optional file name is the name where bytes received directly from the receiver will be collected Full source code is provided Unlike TSIPCHAT TCHAT can be compiled under both Microsoft and Borland Compilers It uses the same source code modules as TSIPCHAT The following modules comprise TCHAT TCHAT C main TSIP RPT C TSIP IFC C SERIAL C Software flow follows the same as TSIPCHAT except that the display and user interface has been greatly simplified It is recommended that software developer s become familiar with TCHAT before studying the source code to TSIPCHAT B 6 Lassen SK8 Embedded GPS Module C Trimble ASCII Interface Protocol TAIP Trimble ASCII Interface Protocol TAIP is a Trimble specified digital communication interface based on printable ASCII characters over a serial data link TAIP was designed specifically for vehicle tracking applications but has become common in a number of other applications because of its ease of use TAIP supports both scheduled and polled responses TAIP messages may be scheduled
190. sage qualifier Time message identifier AA Hours UTC time of day BB Minutes UTC time of day CCCCC Seconds UTC time of day to three decimal places DD Day EE Month FFFF Year GGGGGGGGGGG Reserved fill with zeros lt End of message delimiter Fields AA through GGGG must be downloaded but the remaining fields may be filled with zeros 0 to create a total data stream of 28 characters For warm start performance downloaded time must only be accurate to 5 minutes so the entire field may be filled with zeros However if you wish to specify seconds use a format such as 08150 to represent 8 15 seconds The reserved field GGGGGGGGGGG should be filled with zeros Example When the gt STM1925000002806199400000000000 lt message is sent to the GPS receiver it specifies that the receiver should set its internal time to 19 25 7 25 PM UTC 28 June 1994 The time downloaded to the receiver should be accurate to 5 minutes use UTC not local time for optimum warm start or hot start acquisition C 22 VR Version Number Data String Format XXXXXXX VERSION A AA BB BB BB CORE VERSION C CC DD DD DD E Table C 26 Version Number Data String Descriptions Item of Char UNITS Format Product Name n a n a n a Major Version number 4 n a A AA Major Release Date 8 n a BB BB BB C 26 Lassen SK8 Embedded GPS Module Trimble ASCII Interface P
191. satellite and uses that time The receiver disregards the time in Packet Ox 2E A 36 Lassen SK8 Embedded GPS Module A 17 35 Report Packet 0x55 This packet requests the current I O option states and optionally allows the I O option states to be set as desired Trimble Standard Interface Protocol These abbreviations apply to the following table ALT Altitude ECEF Earth centered Earth fixed XYZ Cartesian coordinates LLA latitude longitude altitude HAE height above ellipsoid WGS 84 Earth model ellipsoid MSL geoid Earth mean sea level mode and UTC coordinated universal time Table A 38 Command Packets 0x55 and 0x35 Data Descriptions Default Parameter Bit Bit Associated Byte Name Position Value Option Packet 0 position 0 LSB 1 XYZ ECEF Output 0x42 or 0 off 0x83 1 on 1 0 LLA Output Ox4A or 0 off 0x84 1 on 2 0 LLA ALT Output Ox4A or 0 HAE datum 0x84 1 MSL geoid Ox8F 17 Ox8F 18 3 0 ALT input 2 0 HAE datum 1 MSL geoid 4 0 Precision of position output 0x42 4A 8F 0 Send single precision 17 packet 1 Send double 0x83 84 8F precision packet 18 0 position 5 0 0 output no Super Ox8F 17 Packets Ox8F 18 1 output all enabled Ox8F 20 Super Packets 6 7 0 not used 1 velocity 0 1 XYZ ECEF Output 0x43 0 off 1 on 1 0 ENU Output 0x56 0 off 1 on 2 7 0 not used Lassen SK8 Embedded GPS Module A 37 Trimble Standard Inter
192. se approximation for the constant PI The value of the constant PI as specified in ICD GPS 200 is 3 1415926535898 A 17 31 Second 0x4A Packet Type Report Packet Ox4A is also sent in response to the setting or requesting of the Reference Altitude Parameters using Command Packet 0x2A These parameters can be used in the Manual 2 D mode Reference Altitude The altitude used for manual 2 D positions if the altitude flag is set Altitude is in units of HAE WGS 84 or MSL depending on the selected I O options for the position A 34 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol Altitude Flag A flag that determines whether or not the Reference Altitude will be used If set it will be used If cleared altitude hold last 3 D altitude will be used The data format is shown in the following table Table A 34 Reference Altitude Item Type Units Reference Altitude SINGLE Meters Reserved SINGLE Altitude flag BYTE A 17 32 Report Packet 0x4B The receiver transmits this packet in response to packets 0x25 and 0x26 and following a change in state In conjunction with Packet 0x46 health of receiver this packet identifies the receiver and may present status messages The machine ID can be used by equipment communicating with the receiver to determine the type of receiver to which the equipment is connected Then the interpretation and use of packets can be adjusted accordingly Table A 35 Rep
193. se measurements which are beneficial for vehicle navigation Differential GPS DGPS is a sophisticated form of GPS navigation which provides even greater positioning accuracy Differential GPS relies on error corrections transmitted from a GPS receiver placed at a known location This receiver called a reference station calculates the error in the satellite range data and outputs corrections for use by other GPS receivers These GPS receivers are designated as mobile units and can be dispersed as far as 100 Km from the base station Differential GPS eliminates virtually all the measurement error in the satellite ranges and enables a highly accurate position calculation The Lassen SK8 is differential ready for applications requiring DGPS accuracy Scope and Audience Even if you have used other Global Positioning System GPS receivers we recommend that you spend some time reading this manual The following section provides you with a guide to this manual as well as to other documentation included with this product Lassen SK8 Embedded GPS Module xix Preface Lassen SK8 Manual Organization All of the information required to integrate and operate theLassen SK8 is contained in this Manual This manual contains the following chapters and appendices Chapter 1 Starter Kit Chapter 2 Hardware Integration Chapter 3 Software Interface Chapter 4 Operation and Performance Appendix A Trimble Standard Interface Protocol Appendix B TSIP
194. se settings are kept in BBRAM Battery Backed Random Access Memory and can be saved into non volatile memory if desired The commands include TSIP command OxBC TAIP command PT Refer to Appendix A 3 Customizing Receiver Operations for additional information on protocols If the receiver is not talking to application programs the ports may be configured to an unknown setting Use the following Toolkit program commands to return the receiver to the factory default setting TSIP SK8BREAK TAIP SK8TAIP 3 4 4 TSIP Data Output The Trimble Standard Interface Protocol TSIP is the native language for the Lassen SK8 TSIP is a binary language with a wide variety of commands and reports TSIP reports can be output automatically or they can be output as responses to queries The format of the automatic reports can be easily configured Refer to Appendix A 3 Customizing Receiver Operations and Appendix A 4 Automatic Position and Velocity Reports for further information The receiver is shipped from the factory configured for single precision Latitude Longitude Altitude Customized position and velocity formats can be created by using the information in Appendix A 3 Customizing Receiver Operations The TSIPCHAT program in the Lassen SK8 Starter Kit permits using a computer keyboard to send the Request Packets to the GPS receiver The responses to these requests are then displayed on a DOS computer screen in ASCII format C sou
195. sed 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 Lassen SK8 Embedded GPS Module NMEA 0183 E 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 4 satellites are in view Fields 1 and 2 indicate the total number of messages being sent and the number of each message respectively GSV X X XX XX XX XXX XX XX XX XXX XX XXX XX XX XX XXX XX Table E 6 GSV GPS Satellites 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 f Satellite SNR C No Null When Not Tracking 8 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 Lassen SK8 Embedded GPS Module E 5 NMEA 0183 E 6 E 4 5 E 4 6 RMC Recommended Minimum Specific GPS Transit Data The RMC message c
196. sirable because position jumps may be experienced when SA 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 mask is set to five degrees and provides a reasonable trade off of the benefits and drawbacks High accuracy users may prefer a mask angle around ten degrees where the ionosphere and troposphere begin to be more predictable 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 The factory default mask has been set to zero High accuracy users may use a slightly higher mask of 6 0 8 0 since weaker measurements may be slightly noisier and are often caused by reflected signals which provide erroneous ranges One should also resist the temptation to set the elevation and SNR masks too low The satellite geometry is sometimes improved considerably by selecting low elevation satellites They 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 therefore more difficul
197. solution of 160 ns Software techniques such as over determined clock algorithm can achieve PPS accuracy greater than Selective Availability because more satellites are used to give a higher timing accuracy Serial Time Output Both the TSIP TAIP and NMEA protocols include time messages Refer to Report Packet 41 in Appendix A or the ZDA descriptions in Appendix D for a description of the time reports for each protocol and the TAIP TM message Note GPS time differs from UTC Universal Coordinated Time by a variable integer number of seconds UTC GPS time GPS UTC offset As of June 1997 the GPS UTC offset was 11 seconds The offset has historically increased by 1 second about every 18 months System designers should plan to read the offset value as a part of the timing interface to obtain UTC The GPS week number is in reference to a base week Week 0 starting January 6 1980 Lassen SK8 Embedded GPS Module Operation and Performance 4 9 2 Timing Pulse Output PPS A pulse per second PPS ten microsecond wide pulse is available on the Lassen SK8 8 pin interface connector The pulse is sent once per second and the rising edge of the pulse is synchronized with UTC The pulse shape is affected by the distributed capacitance of the attached cabling and input circuit The rising edge is typically less than 20 ns wide The falling edge should never be used for timing applications Note The PPS signal output
198. ss s XxX XX XXXX XX XX Table E 9 ZDA Time amp Date Message Parameters Field Description 1 UTC Day 01 to 31 Month 01 to 12 Year Local Zone Description Hours 13 hours Local zone description is the number of whole hours added to local time to obtain UTC The zone description is always negative for eastern longitudes Local Zone Description Minutes Local zone description minutes using the same sign convention as local zone hours Note Fields 5 6 are null fields the Lassen SK8 output A GPS receiver cannot independently identify the local time zone offsets Lassen SK8 Embedded GPS Module E 7 NMEA 0183 E 8 Lassen SK8 Embedded GPS Module F Specifications and Mechanical Drawings The Lassen SK8 module is designed for embedded industrial computing or control mobile computing or data collection precision timing and vehicle tracking applications This appendix includes the system specifications and mechanical drawings for the Lassen SK8 receiver module and the miniature magnetic mount GPS antenna F 1 GPS Receiver F 1 1 General 11 frequency 1575 42 MHz C A code Standard Positioning Service 8 channel continuous tracking receiver 32 correlator F 1 2 Accuracy Position 25 meters CEP 50 without SA Selective Availability Velocity 0 1 m sec 1 Sigma steady state conditions without SA Time UTC to nearest microsecond with 1 pulse per se
199. t available C 16 Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP C 15 PR Protocol The protocol message PR is the method used to control which I O protocols are active on each of the two Lassen SK8 ports Each protocol can be set to Off Input Only Output Only Both Input and Output The PR data string format is TAIP xy TSIP xy NMEA xy RTCM xy Table C 15 PR Data String Descriptions Item of Char UNITS Format Value Port 1 Protocol 1 n a X T Both in and out Port 2 Protocol 1 n a y Input only O Output only F Off N Not Available There are two restrictions to setting protocols is input only TAIP cannot be running on both ports at the same time DX Note If a protocol is not implemented within the application x and or y will have the value N and any set message for that protocol is ignored It is possible to turn off all input processing on a port If this is done neither TAIP nor TSIP can be used to change the active protocols The break sequence must used If you do not use battery back up all port characteristics will reset to the default after power is removed Lassen SK8 Embedded GPS Module C 17 Trimble ASCII Interface Protocol TAIP C 16 PT Port Characteristic Data String Format AAAA B C D Table C 16 Port Characteristic Data String Description
200. t is reported in the auto lower window The common automatic reports are the navigation reports position velocity and health data The CTRL O command can change the content of these auto reports or turn them on and off Other automatic reports include almanac ephemeris status and almanac health page when decoded and receiver health machine code status and satellite selection at regular intervals Lassen SK8 Embedded GPS Module TSIP User s Guide Command Packets TSIPCHAT uses keystroke codes to send TSIP Packet packets to the receiver For instance the keystroke v sends the TSIP Packet Ox1F requesting a TSIP Report Packet 0x45 listing the software versions A complete list of keystrokes and their associated TSIP commands can be called up by pressing the key Many TSIP command packets require user provided data or parameters For instance a request for a satellite almanac report packet requires the satellite identifier SV PRN In such cases TSIPCHAT will prompt the user for inputs For any of the following three type of prompts pressing the CTRL Z keys or ESCAPE key aborts the whole command 1 prompt for number to enter a numerical value type the value and hit ENTER If no value is typed the value entered will be 0 2 prompt for selection to select from a number of choices cycle through the choices with the SPACE BAR and select with ENTER An index 0 9 associated with the choice is shown
201. t 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 DOP Mask and Switch The DOP mask is the maximum DOP limit for any 2 D or 3 D position solution will be made The DOP 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 in either manual mode Raising the DOP mask will generally increase the fix density during obscuration but the fixes with the higher DOP will be less accurate especially with SA present Lowering the mask will improve the average accuracy at the risk of lowering the fix density Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 15 6 Packet OxBB Set DGPS Mode Packet OxBB is used to set the differential GPS operating mode The factory default mode is OFF If differential corrections are available the recommended mode is DGPS Auto In this mode the receiver computes differentially corrected positions whenever valid corrections are available Otherwise the receiver computes non differentially corr
202. te number of weeks since the beginning of GPS time or 06 January 1980 If the true GPS Week Number is desired the system developer should ignore the extra MSBs of the Extended GPS Week Number and use only the 10 LSBs 3 6 Differential GPS 3 8 The Lassen SK8 module can use differential corrections to compute a Differential GPS position DGPS DGPS can provide position accuracy of 2 meters 1 sigma RTCM SC 104 the industry standard format for differential corrections is available from most DGPS reference stations Coast Guard beacon transmissions and commercial DGPS subscription services The Lassen SK8 is fully compatible with RTCM SC 104 Version 2 1 The Lassen SK8 is configured to accept RTCM SC 104 correction data over port 2 J4 pin 7 at 4800 baud 8 data bits 1 stop bit and no parity The DGPS operating mode is set to Automatic which means that the receiver will provide differential GPS solutions when valid correction data is available and will output standard GPS solutions when no valid correction data is available No setup is required to use RTCM SC 104 differential corrections however you may need to reconfigure the serial port characteristics baud rate data bits stop bits and parity to match the characteristics of your RTCM SC 104 data source using the TSIP packet BCh See Appendix A for more information on this message Table 3 1 summarizes the default characteristics for the Lassen SK8 serial ports Lassen SK8 Embedd
203. te time The receiver calculates the elevation and expected Doppler shift for each satellite in this expected set and directs the eight tracking channels in a parallel search for these satellites Lassen SK8 Embedded GPS Module Operation and Performance 4 2 3 4 2 4 The warm start time to first fix when the receiver has been powered down for more than 60 minutes i e the ephemeris data is old is usually less than 45 seconds Garage Search Strategy During a warm start search the Lassen SK8 knows which satellites to search for based on the system almanac the initial position last known position and the current time In some cases the receiver may not be able to acquire the expected satellite signals e g a vehicle parked in a garage or a vessel in a covered berth 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 5 minutes of power on some of the eight tracking channels will continue to search for the expected satellites warm search while the remaining channels are 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 The stored information is flushed from memory if the cold start search proves effective and the warm search fails Hot Start A hot start strategy applies when the Lassen SK8 has been power
204. ted by the GPS control segment Consequently the GPS constellation can be considered a set of 24 orbiting clocks with worldwide 24 hour coverage GPS receivers use the signals from these GPS clocks to correct its internal clock which is not as stable or accurate as the GPS atomic clocks GPS receivers like the Lassen SK8 output a highly accurate timing pulse PPS generated by its internal clock which is constantly corrected using the GPS clocks This timing pulse is synchronized to UTC within 500 ns In addition to serving as a highly accurate stand alone time source GPS receivers are used to synchronize distant clocks in communication or data networks This synchronization is possible since all GPS satellite clocks are corrected to a common master clock Therefore the relative clock error is the same regardless of which satellite or satellites are used For timing applications requiring a common clock GPS is the ideal solution GPS time accuracy is bounded by the same major source of error affecting position accuracy Selective Availability 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 ns The hardware and software implementation affects the GPS receiver s PPS accuracy level The receiver s clocking rate determines the PPS steering resolution The Lassen SK8 clocking rate is 3 126 MHz This rate corresponds to a steering re
205. ted doppler Table A 48 Report Packet 0x5A Data Formats Item Type Satellite PRN Number BYTE Sample Length SINGLE Signal Level SINGLE AMU or dBHz Code phase SINGLE 1 16th chip Doppler SINGLE Hertz Time of Measurement DOUBLE sec Application Note Packet 0x5A provides the raw satellite signal measurement information used in computing a fix Satellite PRN Byte 0 is a unique identification number or each of the 32 GPS satellites Sample length Byte 1 is the number of milliseconds over which the measurement was averaged thus if the sample length is 428 then the receiver tracked the satellite and collected the measurement over a 428 millisecond period The receiver uses a 500 millisecond dwell time per satellite however if the channel is sequencing on several satellites the sample length will be closer to 400 milliseconds due to re acquisition and loop setting times 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 The doppler Byte 13 value is apparent carrier frequency offset averaged over the sample interval It is measured with respect to the nominal GPS L1 frequency of 1575 42 MHz referenced to the receiver s internal oscillator Thus it includes
206. tely every 19 years 8 months August 1999 is the first roll over for the GPS system since the beginning of GPS time on 06 January 1980 Lassen SK8 Embedded GPS Module 3 7 Software Interface The following two known issues for previous versions of receivers exist as a result of testing a representative sample of Trimble OEM receivers An almanac recorded prior to WNRO is not correct after WNRO This problem only exists when the receiver main power is OFF and battery back up power is ON at the moment of WNRO Once the receiver is cold started a post WNRO almanac is collected and the receivers behavior returns to normal e Day month year representations will be incorrect after WNRO when using specific TAIP and NMEA messages Time and day information will not be effected however There is no impact for TSIP users on position or time information The reported GPS week number will reset to zero however and users that require this information may need to make a software modification to accommodate this change ACE GPS Palisade Family Firmware Version 7 xx Software Modifications The Lassen SK8 receiver has been designed to handle WNRO and there are no problems with either dates or the first fix after WNRO through the year 2015 Caution Trimble OEM GPS receivers have reported the true GPS Week Number in TSIP messages 0x41 and 0x8F 20 as a number between 0 and 1023 The Lassen SK8 however outputs the Extended GPS Week Number as the absolu
207. ters time of fix SINGLE seconds The time of fix is in GPS time or UTC as selected by the I O timing option Ww 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 p PI The value of the constant PI as specified in ICD GPS 200 is 3 1415926535898 Lassen SK8 Embedded GPS Module A 57 Trimble Standard Interface Protocol A 17 57 Report Packet 0x85 This packet provides the status of differential corrections for a specific satellite It is sent in response to Packet 0x65 The format of this packet is shown in Table A 65 Table A 65 Report Packet 0x85 Data Formats Report 85 Byte Item Type Satellite PRN number BYTE Summary status code BYTE Station health BYTE Satellite health UDRE BYTE IODE 1 BYTE IODE 2 BYTE Z count as Time of Week SINGLE seconds Range correction SINGLE meters Range rate correction SINGLE m sec Delta range correction SINGLE meters The summary status code is encoded in Table A 66 Table A 66 Report Packet 0x85 Summary Status Code Encoding good correction data good delta correction data station health bad 5 or 7 data too old 60 seconds UDRE too high gt 4 IODE mismatch with ephemeris satellite not in current Type1 message A 17 58 Packets Ox8bE and 0x8F Refer to
208. that is required by adjusting the report interpreter routines in TSIP RPT C provided the necessary information is contained in the binary input file Software flow follows that of TSIPCHAT except with no user interactive and command features RTCM MON RTCM MON translates RTCM SC 104 Version 2 0 Differential GPS correction byte streams off a serial port It is designed to be configured to the same port parameters as the TSIP receiver RTCM streams can best be tested by using the TSIP receiver itself as a decoder using TSIPCHAT and the 7 command Packet 0x65 which returns Packet 0x85 listing all differential RTCM messages decoded _ MON is provided in case the user prefers to use a direct connection to a computer serial port to decode an RTCM stream The RTCM MON command line has no arguments When listening to the serial port characters will be printed on the screen RTCM 6 of 8 bytes reported as non RTCM bytes Once the program locks onto the RTCM preamble and framing it begins to report differential correction messages for each of the satellites To exit the program press ESCAPE Bit Slipping Even though the RTCM bytes are 6 bits of data and fit neatly into a 8 bit byte once the lead bits 01 are attached some reference receivers do not align the RTCM data onto 8 bit boundaries for the serial link bit slipping RTCM MON automatically searches for bit slipping Lassen SK8 Embedded GPS Module B 5 TSIP User
209. that the unit did in fact receive the intended data FR Flag indicates whether the unit is to report messages automatically per their individually scheduled frequency When set to false the unit will only respond when queried for a specific message CR Flag when set to True will cause the sensor to append a carriage return and line feed CR LF to the end of each message output This is useful when viewing the unencoded sensor responses on a terminal or a PC The default value at start up for ID flag and the CR flag is false the default for CS EC and FR flags is true Example The following command will turn checksums off and carriage return on gt SRM CS_FLAG F CR_FLAG T lt Note Note the use of semicolon before the flag name Lassen SK8 Embedded GPS Module Trimble ASCII Interface Protocol TAIP C 19 RT Reset Mode Data String Format Any one of the following data strings can be set Upper case characters are required COLD FACTORY SAVE CONFIG Table C 19 Reset Mode Data String Descriptions Item of Char Description 0 Warm start COLD 4 Cold start FACTORY 7 Factory Reset SAVE_CONFIG 15 Save serial EEPROM user values The only valid qualifier is SET The SAVE CONFIG data string is the only method of saving the TAIP protocol definition to Serial EEPROM The following command will save the protocol and port definitions to Serial EEPROM
210. the signal can be characterized by some number of parameters that vary slowly with time then Kalman filtering can be used to tell how incoming raw measurements should be processed to best estimate those parameters as a function of time See satellite masks Lassen SK8 Embedded GPS Module Glossary 5 Glossary 2 D maximum PDOP NAVSTAR NMEA NMEA 0183 message packet parity PDOP PDOP constellation switch PRN protocol pseudo range RAM random access memory Glossary 6 Two Dimensional A 2 D position is defined as latitude and longitude Altitude is assumed to be fixed 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 An envelope for data which contains addresses and error checking information as well as the data itself A scheme for detecting certain errors in data transmission Parity defines the condition i e even
211. tional capability of the unit in a network environment This protocol is described in Appendix C Trimble ASCII Interface Protocol TAIP The receiver can easily be configured to TAIP with the program SK8TAIP contained in the Toolkit This program re configures the Lassen SK8 to Default TAIP settings TAIP at 4800 8 none 1 on Port 1 RTCM in silent out at 4800 8 none 1 on Port 2 The program stores these settings along with all the other defaults to non volatile memory The GPSSK program can now be used to control and re configure the receiver Receiver configurations created in GPSSK can be stored in non volatile memory using the RT command As mentioned above the receiver ports can also be set to TAIP through a TSIP port using TSIPCHAT and the TSIP command OxBC Lassen SK8 Embedded GPS Module 3 5 Software Interface 3 6 3 4 3 Configuring the ACE GPS receiver output protocol from TAIP to TSIP protocol TAIP message PR Configuring the receiver output from TAIP to TSIP will display binary data in now displayed on the screen 1 Run GPSSK x Press x to select the Host Computer COM Port 2 the GPS Main screen appears press ENTER 3 Type the following message to set the receiver to TSIP gt SPR TAIP FF TSIP TF lt Where Table 3 2 TSIP Message Description ELEMENT DESCRIPTION Beginning of command sentence The Set Command The TAIP protocol message The desired protocol Port 1 of
212. to less than 20 seconds The receiver will respond to commands almost immediately after power up 3 2 Software Tool Kits Trimble provides a Software Developers Tool Kit to support the TSIP and TAIP protocols The Kit contains a user friendly program to communicate with the receiver and includes sample C source code and reusable routines to aid in developing applications The following Appendices provide additional information TSIP Appendix A Trimble Standard Interface Protocol Appendix B TSIP User s Guide TAIP Appendix D GPSSK User s Guide TAIP Appendix E NMEA 0183 Lassen SK8 Embedded GPS Module 3 1 Software Interface 3 3 Communicating with the Lassen SK8 Module NIZ 3 2 The Lassen SK8 supports three I O message protocols TSIP TAIP and NMEA The protocols are discussed at the end of this chapter and are explained in detail in Appendices through E Communication with the Lassen SK8 module is through two CMOS compatible TTL level serial ports The port characteristics can be changed to accommodate your application requirements Port parameters are stored in a non volatile electrically erasable ROM EEROM that does not require backup power Table 3 1 lists the default characteristics for each port Table 3 1 Default Serial Port Characteristics Input Output Protocol Default Setup Language Default Setup TAIP Baud Rate 4800 TAIP Baud Rate 4800 Data Bits 8 Data Bits 8 Parity Odd Parity Od
213. treams are similar to Report Packets 0x40 0x49 and Ox4F respectively and those reports are preferred To get ionosphere or ephemeris this report must be used A 40 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol Table A 42 Report Packet 0x58 Almanac Data Item Type Meaning FCD 200 Sec No t_oa_raw BYTE Sec 20 3 3 5 1 2 SV_HEALTH BYTE Sec 20 3 3 5 1 2 SINGLE Sec 20 3 3 5 1 2 SINGLE Sec 20 3 3 5 1 2 i_o SINGLE Sec 20 3 3 5 1 2 OMEGADOT SINGLE Sec 20 3 3 5 1 2 sqrt_A SINGLE Sec 20 3 3 5 1 2 OMEGA 0 SINGLE Sec 20 3 3 5 1 2 omega SINGLE Sec 20 3 3 5 1 2 M 0 SINGLE Sec 20 3 3 5 1 2 a 0 SINGLE Sec 20 3 3 5 1 2 a SINGLE Sec 20 3 3 5 1 2 Axis SINGLE Sec 20 3 3 5 1 2 n SINGLE Sec 20 3 3 5 1 2 OMEGA n SINGLE Sec 20 3 3 5 1 2 ODOT n SINGLE Sec 20 3 3 5 1 2 t zc SINGLE Sec 20 3 3 5 1 2 see Note 2 weeknum INTEGER Sec 20 3 3 5 1 2 wn oa INTEGER Sec 20 3 3 5 1 2 DX Note All angles are in radians DX Note 2 If data is not available t_zc is set to 1 0 Table A 43 Report Packet 0x58 Almanac Health Data Item Type Meaning IDC 200 Sec week for health BYTE Sec 20 3 3 5 1 3 SV health BYTE Sec 20 3 3 5 1 3 t for health BYTE Sec 20 3 3 5 1 3 current t oa BYTE units seconds 2048 current week INTEGER Lassen SK8 Embedded GPS Module A 41 Trimble Standard Interface Protocol Table A 44
214. tricity Squared none Note Eccentricity Squared is related to flattening by the following equation e2 2p p2 Command Packet 0x8E 19 This packet allows the user to enable or disable the position report in UTM Universal Transverse Mercator format If bit 4 byte 0 of Command Packet 0x35 is set to double precision the 0 8 18 packets will be enabled If the bit set to single precision the Ox8F 17 packets will be enabled See A 3 for information on saving the settings to non volatile memory Table A 75 Command Packet 0x8E 19Field Description Description Value Subcode 0x19 UTM Status E Enable 0x45 Command Packet 0x8E 20 This packet requests Packet Ox8F 20 or marks it for automatic output If only the first byte 20 is sent an Ox8F 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 as shown in Table A 76 0x37 can also be used for requesting Ox8F 20 if the Ox8F 20 is scheduled for auto output See A 3 for information on saving the settings to non volatile memory Table A 76 Command Packet 0 8 20 Field Descriptions Byte Item Type Meaning 0 Sub packet id BYTE Id for this sub packet always 0x20 1 Mark for Auto report BYTE 0 do not auto report cf bit 5 of Packet 35 1 mark for auto report Lassen SK8 Embedded GPS Module Trimble Standard I
215. uency 1575 42 MHz with received power up to one watt at the antenna F 4 Lassen SK8 Embedded GPS Module Specifications and Mechanical Drawings F 7 Lassen SK8 Crystal Specifications F 7 1 Electrical Operating Frequency 16 368MHz Crystal Frequency 16 368MHz Fundamental Mode Load Capacitance 32 8pF 0 5pF Tolerance Motional Drive Level Calibration 10 ppm max 25 C Stability 05 ppm max 20 C to 70 C 10 ppm max 40 C to 85 C Aging 01 ppm max first year 05 max for 10 years Capacitance Inductance Resistance 0 100 mW Method of measurement IEC Standard 444 Transmission line method Short Term Frequency to Temperature stability 0 07 ppm C Proposed Specification F 7 2 Environmental Temperature SMDevice Reflow Shock G Sensitivity Vibration F 7 3 Mechanical Enclosure Enclosure Style Electrodes Markings on Top Lassen SK8 Embedded GPS Module Operational 40 C to 85 C Storage 55 C to 105 C 0 5 ppm max change after 240 C for 20 seconds 0 5 ppm max change after 5000G 6 msec 5 sine 0 100 5 ppm max per G 0 5 ppm max change 0 008g Hz to 20Hz 0 5 ppm max change 0 05g7 Hz to 100Hz 3 dB octave 100Hz to 900 Hz HC 45 U SMD Lead length 12 7 mm Resistance weld Gold 5 digit Crystal Frequency Manufacturer Name or Logo Date Code or Lot Number F 5 Specifications and Mechanical Drawings
216. uired 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 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 almanac is repeated every 12 5 minutes The ephemeris is repeated every 30 seconds The system almanac contains information about each of the satellites in the constellation ionospheric data and special system messages The GPS system almanac is updated weekly and is typically valid for months The ephemeris contains detailed orbital information for a specific satellite 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 Lassen SK8 module updates its ephemeris and almanac as needed The performance 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 Lassen SK8 Embedded GPS Module 4 1 Operation and Performance 4 2 Satellite Acquisition and Time to F
217. unabr szts 4wH Brats M30 STANTHL Banes ace ancy 27 F gener ELEZ TSUEN Esas Enaz za EZETY a n amr Munoz B9 geet reece Ba amer soos Oa DN so TH GOOBE TAa ro gt secar ELOELFSHEH x We ia ot ie atte Sh m uve fonce een UE LU LCS reser BETSHDR 5 Lugar DFZRZBHM 50087 al uu saeta 29597 2 g B0057 ME 9 NI NI 1nD ino 281 NI ino NI Pur 29 8 nm 25 50 9 4 SNOTSIASU 221 EE Daoud v Leva arvo NOTLATHOSSO ASH Figure 2 7 Lassen SK8 Embedded GPS Module Specifications and Mechanical Drawings v00 9 8c 915 1301 me NN IOS ION D ION IY Q0 L9 8c ae SES 3AIS3HOV IN3NVIARI3d HLM YNNJINY S45 INT 2153A10d NO LYN USATIS HHL 05 38 OL T38V1 L VAS TF ULE 06 GASNIONOD MOA YOUIATIH i NOLLO3IOMd AN IAUISOd NOVA 34 OL NINRId Z cie 9g Tri
218. urned off Checksum The checksum field provides for an optional two digit hex checksum value which is computed as XOR of all characters from the beginning of the sentence up to and including the character If provided the checksum is always the last element of the sentence before the message delimiter The default mode of operation is to include checksum in sentences The use of checksums can help in instances where the communication channel is noisy Example The following message to set the vehicle ID flag on includes checksum gt SRM ID FLAG T 6F The checksum 6F was generated by XOR ing the ASCII codes for and S then XOR ing that result with the ASCII code for R and so forth up to and including the character Message Delimiter The character signifies end of a sentence and is used as the message delimiter Lassen SK8 Embedded GPS Module C 3 Trimble ASCII Interface Protocol TAIP C 2 PX 4 Sample PV Message The Position Velocity Solution PV message is one of the more commonly used TAIP messages and most sensors using TAIP are set by default to output the PV message once every 5 seconds The following analysis of a typical PV message is provided to further explain the TAIP message protocol gt RPV15714 3739438 1220384601512612 1 D 1234 7F Table C 3 and Distance Reporting Message Format Qualifiers ID Meani
219. used to request the communication parameters on Port 1 and Port 2 The table below lists the individual fields within Packet OxBC Table A 71 Report Packet OxBC Field Descriptions Item Type Value None Meaning Port to Change BYTE Port 1 Port 2 Input Baud Rate BYTE oOo None 110 baud 300 baud 600 baud 1200 baud 2400 baud 4800 baud 9600 baud 19200 baud 38400 baud Output Baud Rate BYTE As above As above Data Bits BYTE 7 bits 8 bits Parity BYTE N nnm None Odd Even Lassen SK8 Embedded GPS Module A 61 Trimble Standard Interface Protocol Table A 71 Report Packet 0xBC Field Descriptions Continued Item Meaning Stop Bits 1 bits for 6 8 data bits 2 bits Flow Control OR of bits 0 none 1 RTSCTS 2 transmit Xon Xoff 4 transmit Xany 8 receive Input Protocols OR of bits 0 none 1 TAIP 2 TSIP 8 RTCM Output Protocols 0 none 1 TAIP 2 TSIP 4 Reserved None A 18 TSIP Superpackets A 62 A 18 1 Several packets have been added to the core TSIP protocol to provide additional capability for OEM receivers In OEM packets Ox8E and their Ox8F responses the first data byte is a sub code which indicates the superpacket type For example in Packet Ox8E 15 15 is the sub code that indicates the superpack
220. users The SA 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 SA can combine to produce large position errors The DOD s definition of accuracy under SA is 100 meters 2 dRMS horizontal 2 dimensional 95 of the time In April 1996 the U S government approved plans for disabling SA Differential GPS DGPS Differential GPS is an effective technique for overcoming the effects of SA and other sources of position error DGPS relies on GPS error corrections transmitted by a reference station placed at a known location The reference station compares its GPS position solution to its precisely surveyed position and calculates the error in each satellite s range measurement The industry standard protocol for GPS correction data is RTCM SC 104 The GPS corrections are broadcast to mobile GPS receivers in neighboring areas The mobile receivers incorporate the GPS corrections in their position solution to achieve excellent accuracy For marine applications corrections are typically modulated on marine radio beacon broadcasts For land based applications the correction data can be transmitted over FM sub carrier cellular telephone or dedicated UHF or VHF radio links DGPS can reduce position error to under 5 meters 9596 of the time under steady state conditions The DGPS accuracy is highly depende
221. uter keyboard Helvetica Bold represents a software command button Notes Tips Cautions and Warnings Notes tips cautions and warnings are used to emphasize important information DX Note Notes give additional significant information about the subject to increase your knowledge or guide your actions A note can precede or follow the text it references Tip Indicates a shortcut or other time or labor saving hint that can help you make better use of the product Ww Caution Cautions alert you to situations that could cause hardware damage or software error A caution precedes the text it references Warning Warnings alert you to situations that could cause personal injury or unrecoverable data loss A warning precedes the text it references xxii Lassen SK8 Embedded GPS Module 1 Starter Kit The Lassen SK8 based on Sierra GPS technology delivers an unmatched level of performance for embedded GPS applications Sierra technology is Trimble s 8 channel GPS architecture based on two ASICs the Scott RF ASIC and the Scorpion DSP The Scott RF ASIC features e Double down conversion process Higher sensitivity Lowest power consumption The double down conversion process improves immunity to in band jammers The system provides a higher sensitivity which allows Lassen SK8 to track weak satellites and improves position availability in environments with obscured coverage The Scorpion ASIC
222. w 3 2V the real time clock may not operate over the specified full temperature range Table 2 2 Power Requirements Signal Voltage Current VCC 4 75 to 45 25 200 mA Battery Backup 3 2 to 5 25 OuA with prime power 2uA 3 5V 25 C without prime power Ground The Lassen SK8 receiver module will maintain full performance specification when the prime power line is coupled with less than 100 mV of ripple noise peak to peak from 1Hz to IMHz Note The Lassen SK8 Starter Kit motherboard contains a 3 6V lithium battery 2 4 Serial Interface 2 4 As an embedded design the Lassen SK8 receiver module provides direct CMOS compatible TTL level serial I O The RX and TX signals on the J4 I O connector are driven directly by the DUART on the Lassen SK8 Interfacing these signals directly to a DUART in your application circuitry provides direct serial communication without the complication of RS 232 or RS 422 line drivers Note The serial I O signals on J4 are TTL level They are not inverted or driven to RS 232 levels Lassen SK8 Embedded GPS Module Hardware Integration 2 5 Pulse Per Second A ten microsecond wide CMOS compatible TTL level pulse is available on pin 6 of the J4 I O connector This pulse is issued once per second with the rising edge of the pulse synchronized with UTC The pulse will be shaped by the distributed impedance of the attached signal line and input circuit The rising
223. x 4 5 4 4 Standard Operating Modes 22e 4 5 4 4 1 HX T 4 5 2D Manual me go wo Seg Ath Si RE ts 4 5 SD Manuals ok fade do NET es a a 4 6 2D 3D AUtomatic ORO a a 4 6 4 5 Differential GPS Operating 4 6 4 5 1 IDGPS On AR eon PA Ns dus Tt ee a 4 6 4 5 2 DGPS co ease stt 4 6 4 5 3 DGPS Automatic 4 6 4 5 4 Differential GPS 4 7 4 6 Position Accuracy T bm oh eee a eU dope gta 4 7 Lassen SK8 Embedded GPS Module 4 7 4 8 4 9 4 10 A l A 2 A 3 4 A 5 A 6 8 9 A 10 11 12 A 13 A 14 A 15 Lassen SK8 Embedded GPS Module 4 6 1 Selective Availability 4 7 4 6 2 Differential GPS DGPS le 4 7 Coordinate Systems ux x ROR hh x ok BG Vee m Ae Gok 4 8 4 7 1 TSIP Coordinate 4 8 4 7 2 NMEA OLSI A as XU ese ito aed 4 9 4 7 3 ume EURO Gs d Godel RAUS ud 4 9 Performance Characteristics 2e 4 9 4 8 1 Wpdate Raters od Py ed se e ds A Pete ed 4 9 4 8 2 Dynamic LIMIS oo wad fey ordures e EUROS Ru 4 9 4 8 3 R Acquisition iu x obo uo nor he Se e RUE ROS ed 4 9 GPS TIMIN S
224. x5C satellite tracking status 0x3C 0 6 all in view satellite selection 0x24 auto 0x82 differential position fix mode 0x62 auto 0x83 double precision XYZ auto 0x37 0x84 double precision LLA auto 0x37 0x85 differential correction status 0x65 Ox8F 20 last fix with extra information fixed point auto 0x37 0 8 20 Ox8F 17 UTM auto 0x37 Lassen SK8 Embedded GPS Module A 15 Trimble Standard Interface Protocol A 15 Key Setup Parameters or Packet BB Selecting the correct operating parameters has significant impact on receiver performance Packet OxBB set receiver configuration controls the key setup parameters The default operating parameters allow the receiver to perform well in almost any environment The user can optimize the receiver to a particular application if the vehicle dynamics and expected level of obscuration are understood If the receiver is then taken out of this environment the specifically tuned receiver may not operate as well as a receiver with the default options The table below lists suggested parameter selections as a function of obscuration and whether accuracy or fix density is important In this table NA indicates that the operating parameter is not applicable DC don t care indicates that the user may choose the operating parameter Table A 14 Setup Parameters Factory Packet Parameter Accuracy Fixes Default 0xBB Fix mode Man 3D AUTO AUTO OxBB Dynamics code Land La
225. y Default Settings To reset the receiver configuration to factory default settings use TSIP command Ox1E with data byte F This will negate all previous Ox8E 26 settings Caution Whenever using command Ox8E 26 or Ox1E wait two seconds before removing power This allows the process of writing to non volatile memory to be completed Warning When changing port settings record the new settings for future reference These settings must be used whenever the receiver is powered up If the port settings are lost use theTPRESET program in the Toolkit disk to return the board to the factory default settings Lassen SK8 Embedded GPS Module A 3 Trimble Standard Interface Protocol Table A 2 Customizing Receiver Operation I Os Input ID Description Output ID 0xBB set request query receiver configuration BB OxBC set request query port configuration BC 0x35 set input output options 55 0x70 enable disable PV altitude filters 70 Ox7A set NMEA schedule 7B Ox8E 15 set datums Ox8E 19 enable UTM Ox8E 20 enable superpacket Ox8E 26 save settings Note After setting 2 seconds A 4 Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 4 Automatic Position and Velocity Reports The receiver automatically outputs position and velocity reports at set intervals Automatic report packets are controlled by Packet 35 Setting the control bits as indicated in the table below
226. y healthy satellites based on transmitted values in the ephemeris and almanac which satisfy all mask 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 0x59 for operation modes 3 and 6 only The data format is shown below Table A 47 Report Packet 0x59 Data Formats Byte Item Type Value Meaning 0 Operation BYTE 3 The remaining bytes tell whether receiver is allowed to select each satellite 6 The remaining bytes tell whether the receiver heeds or ignores each satellite s health as a criterion for selection 1 to 32 Satellite 32 BYTES Depends on byte 0 value 1 byte per satellite 0 Enable satellite selection or heed satellite s health Default value Disable satellite selection or ignore satellite s health This information is not held in battery backed memory At power on and after a reset the default values are set for all satellites Lassen SK8 Embedded GPS Module Trimble Standard Interface Protocol A 17 40 Report Packet 0x5A This packet provides raw GPS measurement data If the I O auxiliary option has been selected the receiver sends this data automatically as measurements are taken The data format is shown below Note A new Report Packet 0x 6F has full pseudo ranges and integra

Download Pdf Manuals

Related Search

Related Contents

Descargar PDF - MEDICAL IMOTHEP CA  Sony BRAVIA KDL-20S2000 User's Manual      MANUAL DEL USUARIO USER MANUAL MANUEL D    

Copyright © All rights reserved. Failed to retrieve file