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Navman 11 GPS Receiver User Manual

1. S 61 4 5 Satellite management REENEN CERN NEESS S dee 61 4 5 1 Visible list generation eret rrr nte Ee Dr te EHI D ERE et re tetur ue 61 4 5 1 1 Dilution OF Precision DOP us eost vacet a a a cout teeyaeestevevieete 61 4 5 2 Acquisition modes ere te eee thee eee he aed edo te node ertet e quee tue a e Ee udo tetas Eae uad 62 4 5 2 1 e ett EE 62 MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 4 0 2 2 Parallel ACQUISIION E 62 4 5 2 3 Adaptive threshold based signal deiechon eene 62 4 5 2 4 Overall search el 62 4 5 3 Data colleclons o eu e t mee e patente certes 62 4 9 3 1 loc wats 62 45 32 E 62 4 5 3 3 UTC and ionospheric Corrections nci edi nie n cete nana E Cd RC eo d Eee ERR ER a eed 62 4 6 Navigation irren eani teria atte s ku un E ESS RAS RS RR RR YR SR GERRRRR GS RR RR Ra Sn RE ER RR 64 4 6 1 Geodetic Cette soe dEE 64 4 6 1 1 User selection of geodetic datums tannini inai iaaa EA 64 4 6 1 2 User defined datums riter e e REY e ex yo ER RE 64 4 0 2 Platform laS sce 65 4 6 2 1 Pedestrial E 65 ene 65 e 65 4 0 9 Navigation KEE 65 4 6 3 1 State propagallon EE 65 4 6 3 2 Measurement ele e EE 65
2. Header checksum Sequence number Note 1 0 to 32767 Elevation mask angle 0 to n 2 8 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Table 3 26 Message 1212 satellite elevation mask control Message ID 1213 Rate as required maximum rate 1 Hz Message length 10 words Word No Name Message header Header checksum Sequence number Note 1 0 to 32767 Satellite PRN 1 i 1 included Satellite PRN 16 i 1 included Satellite PRN 17 i 1 included Satellite PRN 32 i 1 included 1 store in non volatile memory 9 0 Non volatile storage select 9 1 9 15 Reserved 10 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Table 3 27 Message 1213 satellite candidate select MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 35 3 5 2 6 Message 1214 DGPS control This message allows the user to control the behavior of the receiver s differential capability Storage of this message s parameters requires EEPROM The contents of the DGPS control message are described in Table 3 28 3 5 2 7 Me
3. Note 4 The data displayed by this field is not valid until the receiver is in navigation mode Table 3 10 Message 1009 ECEF position output MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 20 3 5 1 7 Message 1011 receiver ID this message are also honoured This message This message is output automatically at start up consists of five 20 byte two characters per word after the receiver has completed its initialisation null padded ASCII data fields The contents of the It can be used to determine when the receiver is receiver ID message are described in Table 3 11 ready to accept serial input Manual requests for Message ID 1011 Rate variable see above Message length 59 words Word No Message header Header checksum Set time Note 1 10 ms ticks 0 to 4294967295 Sequence number Note 2 0 to 32767 Number of channels 19 28 Software version 29 38 Software date 39 48 Options list Note 3 49 58 Reserved Ul 59 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is a
4. iei isinan anaa creep ose eter snes db EE etd ENEE ENNER 58 4 1 3 Electrically Erasable Programmable Read Only Memory EEPROMWM esses 58 41 4 Read Only Memory ROM reinen nene nnne tenute than een kn nnne nha Ea ea pete n Ese innui 58 SAEUL EE 58 4 21 Beflnitlon Seege eie tene tee it etes tei t anti ane 58 4 2 2 Position Velocity Time PVT data eene nnne nter tnn Eada asi 58 4 2 3 Satellite Genee x uico to teet itc mec cene tna Edi ENEE Sie esheets 58 4 24 uU umma ik 58 4 2 5 Universal Time Coordinated UTC and ionospheric parameters 58 e We wr 59 Lasso 59 43 2 Geodetic I R ih 59 4 3 3 Satellite Selection EE 59 4 3 4 Differential GPS DGPS control eren eerte rentrer eiee RR EPEA Eai Eais 60 4 3 5 Cold Start control EE 60 4 3 6 Solution validity criteria o ee eret Pere EORR ER ge EE UE ae Eee edes ee 60 e User entered altitude eir ete rere ee rfe cdi A a ie 60 4 3 9 Vehicle platformiselect tritt cee t rrr rr HRS IE HR Scr RE deeg 60 4 3 9 Navigation COMM lies E Rn 60 4 3 10 Configuration EC 60 4 3 10 1 National Marine Electronics Association NMEA Select 60 4 3 10 2 ROM defaults niin Ge ege ees ee eg 60 4 4 Start up Ru EE 60 4 4 lt EE GE 60 4 42 MASE TEE 60 e ER ln GETT 60 LE E Meri me
5. 4 7 Support functions This section describes the support functions of the GPS receiver 4 7 1 Serial communication interfaces Jupiter GPS receivers provide two bi directional serial communication interfaces the host and auxiliary ports see Section 3 4 7 1 1 The host port The Host port is the primary interface to the controlling application and provides all the services for initialising and configuring the system as well as for the reporting of the navigation solution and receiver status By default the Host port is configured for 9600 baud no parity 8 data bits and 1 stop bit The Navman binary communications protocol is the default selection for the Host port The default settings configuration and protocol can be overridden with the use of the NMEA Select control line of the interface When this line is asserted the configuration defaults to 4800 baud no parity 8 data bits and 1 stop bit and the communications protocol defaults to NMEA Note that the NMEA Select line will override any previously stored selections for the Host port configuration and communication settings While using the Navman binary communications protocol on the Host port a number of application specific parameters can be configured to customise the receiver for a specific application The ability to freely switch between Navman binary and NMEA modes provides full capability to all users Host port output messages can be configured us
6. direct differential RTCM SC 104 data capability for improved positioning accuracy available in both Navman binary and NMEA host modes static navigation enhancements to minimise wander due to SA Selective Availability designed for passive or active antennas for lowest system cost adaptive threshold based signal detection for improved reception of weak signals maximum navigation accuracy achievable with the Standard Positioning Service SPS enhanced TTFF upon power up when in a keep alive power condition before start up meets strict shock and vibration requirements including low frequency vibration automatic altitude hold mode from three dimensional to two dimensional navigation automatic cold start acquisition process when no initialisation data is entered by user maximum operational flexibility and configurability via user commands ability to accept externally supplied initialisation data three satellite navigation start up from acquisition user selectable satellites user selectable visible satellite mask angle MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 1 0 Introduction This document provides technical information common to the entire Navman Jupiter series Navman s Jupiter series of Global Positioning System GPS receivers are single board 12 parallel channel receiver engines Each board i
7. message message 1217 4 6 5 Mean Sea Level MSL MSL is a geoid or surface of equal gravitational potential The height of the MSL geoid above or below the reference ellipsoid WGS 84 by default is called the geoidal separation Positive geoidal separation means that the geoid is above the ellipsoid Values for the geoidal separation are computed at any receiver position by interpolating on the table of geoidal separation values provided in the U S Government document Department of Defense World Geodetic System 1984 Altitude or height computation is referenced to the ellipsoid and is referred to as geodetic altitude Altitude referenced to the geoid usually referred to as altitude MSL can be computed as the geodetic altitude minus the geoid separation 4 6 6 Magnetic variation The magnetic variation model used in the receiver is derived from the full International Geomagnetic Reference Field IGRF 95 magnetic model Documentation tabular data and test programs for the IGRF 95 magnetic model can be obtained from the National Oceanic and Atmospheric Administration NOAA National Geophysical Data Centre NGDC web site http julius ngdc noaa gov seg potfld geomag html The magnetic variation is used to convert true heading to magnetic heading It is output in binary Message 1000 To convert the true course provided in binary Message 1000 to magnetic heading the magnetic variation is added to the true course
8. Horizontal dilution of precision Note 3 1 96 VDOP Checksum lt CR gt lt LF gt Sentence terminator Vertical dilution of precision Note 3 2 70 lt CR gt lt LF gt Note 1 Mode operating M manual forced to operate in 3D mode 3D Note 2 Mode fix 1 fix not available 2 2D 3 3 D A automatic can automatically switch between 2D and Note 3 DOPs are based on the set of satellites above the elevation mask angle this may differ from the set used for navigation Table 3 48 GSA message GPS Message ID GSV DOP and active satellites Rate variable defaults to 0 5 Hz Fields 19 Field No Symbol Field description Field type Example GSV Start of sentence and address field GPGSV MAX MSG _ Total number of messages 1 to 3 2 NUM MSG message number 1 to 3 1 1 2 3 NUM SATS Total number of satellites in view 4 07 SAT PRN Satellite PRN number Note 1 Xx 24 Elevation in degrees 90 degrees maximum Note 2 Xx Azimuth in true degrees 000 to 359 Note 2 Xxx SNR C No 00 to 99 dB null when not tracking Xx 2nd satellite PRN number elevation azimuth SNR Note 1 XX XX XXX XX 3rd satellite PRN number elevation azimuth SNR Note 1 XX XX XXX XX 4th satellite PRN number elevation azimuth SNR Note 1 xx xx Xxx xx 75 CKSUM Checksum hh
9. Navman proprietary receiver ID Recommended minimum specific GPS data Course over ground and ground speed NMEA mode is selected according to the logic described in the appropriate Jupiter reciever data sheet NMEA messages are transmitted and received across the host port serial I O interface RS 232 with the following default Navman proprietary Jupiter channel communications parameters 4800 bps no parity 8 status data bits 1 stop bit This interface conforms with the NMEA 0183 version 2 01 specification command Navman proprietary log control message Navman proprietary receiver initialisation Navman proprietary protocol message 3 6 1 NMEA output message descriptions 3 6 1 1 Navman proprietary Built In Test BIT results This proprietary message provides detailed test results when a BIT is commanded Non zero device failure status indicates failure The contents Standard query message of the BIT message are described in Table 3 45 Enable by default at power up Sample message Once at power up reset PRWIBIT 0001 0000 0000 0000 0000 0000 0 0 15 640 01 02 75 Table 3 44 Jupiter NMEA data messages Message ID BIT Rate Variable Fields 11 Field No Field description Field type Example PRWIBIT Start of sentence and address field Note 1 PRWIBIT ROM FAIL ROM failure Note 2 0001 RAM FAIL RAM failure Note 2 0000 EEP FAIL EEPROM failure Note 2 0000 DPR FAIL D
10. lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Note 1 The visible satellites may include one or more that are below the horizon Since NMEA does not account for negative elevation angles the elevation field will be null for these satellites Note 2 Azimuth and elevation are null when the satellite is in track but a visible list is not available Table 3 49 GSV message GPS satellites in view MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 50 3 6 1 6 Navman proprietary receiver ID RID serial input The contents of the RID message are This message is output automatically at startup described in Table 3 50 after receiver initialisation is complete it can also be requested manually It can be used to determine when the receiver is ready to accept PRWIRID 12 00 90 12 25 95 0003 40 Sample message Message ID RID Rate variable see above Fields 5 Field No Symbol Field description Field type Example RID Start of sentence and address field PRWIRID NUM_CHN Number of channels XX 12 SW_VER Software version X X 00 90 SW_DATE Software date CCCCCCCC 12 25 95 OPT_LST Options list Note 1 hhhh 0003 RES Reserved CKSUM Checksum hh 40 lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Note 1 The options list is a bit encoded configuration word represented as a four digit hexadecimal
11. Digital signal processor DSP failure Note 3 UI Real time clock RTC failure Note 3 UI Serial port 1 receive error count UI 0 to 65535 Serial port 2 receive error count Ul 0 to 65535 Serial port 1 receive byte count Ul 0 to 65535 18 Serial port 2 receive byte count UI 0 to 65535 19 Software version UI 0 00 to 655 35 0 01 20 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 A value of zero indicates a test has passed A non zero value indicates a device failure Missing devices will be reported as failures Therefore the OEM s BIT pass fail should ignore words for components that are not in the system under test Notice that the Dual Port RAM Failure test is currently not implemented Therefore word 12 will report a value of zero Table 3 13 Message 1100 BIT Results MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without not
12. Message ID 1211 Rate as required maximum rate 1 Hz Message length 8 words Word No 1 4 Name Message header 5 Header checksum Sequence number Note 1 0 to 32767 UI 0 to 188 and 300 to 304 6 7 Datum ID Note 2 8 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 2 Appendix B contains map datum codes from 0 to 188 Codes 300 to 304 are user defined Table 3 25 Message 1211 map datum select MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 34 3 5 2 4 Message 1212 satellite elevation mask 3 5 2 5 Message 1213 satellite candidate select control This message allows the user to construct the list This message allows the user to set the elevation of satellites which will be considered for selection mask angle used by the receiver to select visible by the receiver The contents of the satellite satellites Storage of the Elevation Mask Angle candidate select message are described in parameter requires EEPROM The contents of Table 3 27 the satellite elevation mask control message are described in Table 3 26 Message ID 1212 Rate as required maximum rate 1 Hz Message length 8 words Word No Name Resolution Message header
13. Visible satellites Map datum select Differential GPS status Satellite elevation mask control Channel measurement Satellite candidate select ECEF position output Differential GPS control Receiver D Cold start control User settings output Solution validity criteria Built in test results User entered altitude Input UTC time mark pulse output Application platform control Frequency standard parameters in use Nav configuration Power management duty cycle in use Perform built in test command Serial port communication parameters in use Restart command EEPROM update Frequency standard input parameters EEPROM status Power management control Frequency standard table output data Flash boot status Serial port communications parameters Factory calibration input Error status Frequency standard table input data Message protocol control Raw DGPS RTCM SC 104 data Flash re program request Enable by default at power up Once at power up reset Table 3 4 Jupiter binary data messages MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 13 3 5 Jupiter binary data messages This section describes the binary data messages of the Jupiter GPS receiver All output and input binary messages are listed in Table 3 4
14. 1 9 15 Reserved 10 11 Almanac failure Note 3 Bit 12 13 Failure Note 4 Bit 0 to 31 14 15 Almanac status Note 3 Bit 16 17 Status Note 4 Bit 0 to 31 18 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 The Almanac Failure and Almanac Status words are 32 bit bit maps where the LSB PRN 1 and the MSB PRN 32 Note 4 The failure and status words are bit maps with values as follows 0 status 16 DGPS control 1 position 17 host port protocol selection 2 UTC lono 18 auxiliary port protocol selection 3 frequency standard cubic parameters 19 host port enabled messages 4 host port communication configuration 20 reserved auxiliary port enabled messages 5 auxiliary port communication configuration 21 user datums 6 memory options 22 frequency temperature table 7 solution validity criteria 23 reserved 8 power management selections 24 frequency standard calibration data
15. 121 7 2 3 4 5 6 7 8 9 DATE Date dd mm yy XXXXXX 160496 1 MAG_VAR Magnetic variation degrees X X 13 8 LE MAG_REF Magnetic variation E east W west Note 2 a E CKSUM Checksum hh 55 lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Note 1 The position status flag will be set to V data invalid until the receiver is navigating At that time the flag is changed to A data valid and the information provided in the RMC message will reflect a navigation solution Note 2 Easterly variation E subtracts from true course Westerly variation W adds to true course Table 3 51 RMC message recommended minimum specific GPS data MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 52 3 6 1 8 Course over ground and ground speed described in Table 3 52 VTG Sampl This message contains the course over ground CC true and magnetic and speed relative to the GPVTG 291 3 T 277 3 M 0 784 N 1 452 K 4F ground The contents of the VTG message are Message ID VTG while receiver is in navigation mode Note 1 Rate Variable Fields 8 Field No Field description Field type Example VTG Start of sentence and address field GPVTG TRU CRS Course over ground degrees true 291 3 T True course indicator T MAG CRS Course over ground degrees
16. 185 Wake Island Astro 1952 Wake Atoll 15 276 57 149 186 WGS 1972 Global Definition 20 0 0 0 187 Yacare Uruguay 15 155 171 37 188 Zanderij Suriname 15 265 120 358 MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 87 WGS 84 Default Mahe 1971 Adindan Marco Astro AFG Massawa AIN EL ABD 1970 Merchich Anna 1 Astro 1965 Midway Astro 1961 ARC 1950 Minna ARC 1960 Nahrwan Masirah Island Ascension Island 1958 Narhwan United Arab Emirates SINIJA o Astro Beacon E Nahrwan Saudia Arabia Astro B4 SOR ATOLL Namibia Astro POS 71 4 Naparima BWI Astronomic Station 1952 Australian Geodetic 1966 NAD 27 Conus NAD 27 Alaska Australian Geodetic 1984 NAD 27 Bahamas Bellevue IGN NAD 27 San Salvador Island Bermuda 1957 NAD 27 Canada Bogota Observatory NAD 27 Canal Zone Campo Inchauspe NAD 27 Caribbean Canton Island 1966 NAD 27 Central America Cape NAD 27 Cuba Cape Canaveral NAD 27 Greenland Carthage NAD 27 Mexico Chatham 1971 North America 1983 Chua Astro Observatorio 1966 Corrogo Alegre Old Egyptian 1960 Djakarta Batavia Old Hawaiian DOS 1968 Oman Easter Island 1967 Ordinance Survey of Great Britain European 1950 Pi co de las
17. 4 6 3 3 Altitude DFOCESSING EE 65 46 34 POSION PINMNO EE 65 4 6 3 5 Ground track SMOOTHING EE 66 4 6 4 S olution Valdina a E alae i ia eA ana 66 4 6 4 1 Altitude measurement validity criterion eese 66 4 0 4 2 DGPS used validity CETeFIOFL EE 66 4 6 4 3 Number of satellites used validity criterion seen 66 4 6 4 4 Maximum EHPE validity criterion essent 67 4 6 4 5 Maximum EVPE validity criterion eese eene 67 46 5 Mean Sea Level MSL M 67 4 6 6 MaQmetic Varlatlon e rede 67 4T Support Tunctlons ET 67 4 7 1 Serial communication interfaces enne emen nnne nnne 67 E Re Ee c M E 67 44 1 2 The auxiliary DOME EE 68 4 72 EEPROM SE60VICES ciini brote arii teoon s Hee ue ce i ie ae aaa 68 ATS RTO SEVICE Si einem n Cae doeet te tele terere 68 4 7 4 Differential GPS EE 68 4 4 1 THE RAGM protoCol EE 69 RRE 69 4 7 4 3 Compliance with RTCM SC 104 reouirements sess 69 4 7 4 4 DGPS initialisation and configuration sese 69 4 74 5 Disabling DGPS operation sete eat deed R ENEE wae eevee 70 4 54 0 DGPS T6S6l EE 70 4 L4 7 DGPS Status request rate eret t Re cds ERE ae o eade ta sha SS tH HERE REP EEA EEEE 70 47 5 BuiltsIm Test BE EE 70 4 7 5 1 Interpreting BIT results ie A t Ee oes Alene EE EEGEN 70
18. 9 selected datum 25 nav configuration data 10 platform class 26 DR navigation parameters 11 cold start control 27 gyro temperature table 12 elevation mask angle 28 reserved 13 satellite candidate list 29 reserved 14 antenna selection 30 reserved 15 user entered altitude 31 data is being updated Table 3 19 Message 1136 EEPROM status MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 30 3 5 1 16 Message 1160 frequency standard table message will be used in conjunction with Message output data 1360 to retrieve and restore this information for This message contains parameters and table external storage The contents of the frequency data used in the receiver s frequency standard standard table output data message are described compensation model It is intended that this in Table 3 20 Message ID 1160 Rate variable Message length 270 words Word No Type Units Resolution Message header Header checksum 0 to 4294 967 295 Sequence Number Note 2 0 to 32767 Table frequency offset Note 3 0 to x51 10 0 Table frequency offset valid Note 4 i 1 valid 10 1 10 15 Reserved 11 Offset error estimate Note 5 0 to 51 Set time Note 1 10 ms ticks 12 Aging rate estimate Note 6 0 to 5 13 Last rate update week Note 7 0 to 32767 Frequency standard table Note 8 LSB 0
19. As soon as the DGPS function is enabled the most current data will be used to compute a position solution 4 7 4 6 DGPS reset The user may also reset the DGPS process at any time using the Differential GPS Control message binary Message 1214 When this is done the DGPS data currently stored in the receiver is invalidated or replaced by its default values This discontinues DGPS service until new RTCM SC 104 and ephemeris data is collected A DGPS reset is different from the type of reset initiated by power on or an initialisation message system reset During a DGPS reset DGPS disable and correction timeout are unaffected If values have been previously entered for these words these same values will be in effect both before and after the DGPS reset If new valid entries for these words are received within a DGPS control message that also contains a reset then the new values will be in effect after the reset However after a DGPS reset all other DGPS parameters will be set to their default values 4 7 4 7 DGPS status request The user may request that the status of DGPS operation be provided When requested the DGPS status message binary Message 1005 provides information on the state of each of the corrections being processed In the event that DGPS solutions are not available the status message also provides enough diagnostic data for the user to determine why they are not being computed 4 7 5 Built
20. IPRO 3 6 2 5 Standard query message Q This message is used to request a one time output of any of the approved NMEA messages from the Jupiter receiver The typical response time between receipt of a query and the transmission of the requested message is approximately one second The contents of the Q message are described in Table 3 58 Sample message LCGPQ GSV Rate as required Fields 2 Field No Symbol Field description PRWIIPRO Start of sentence and address field Note 1 Field type Example PRWIIPRO RES Reserved PRO_TYPE Protocol type RBIN Navman binary RBIN CKSUM Checksum optional lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Note 1 NMEA message prefix P Proprietary message indicator RWI Navman Systems Inc mnemonic INIT Initialisation message ID Table 3 57 IPRO message Navman proprietary protocol message Message ID Q Rate as required Fields 1 Field No Symbol Field description Start of sentence and address field Note 1 Field type Example LCGPQ requested CKSUM Checksum optional Approved sentence formatter of the data being GSV lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Note 1 The identifier of the device from which data is being requested refer to paragraph 5 4 4 of this chapter must be GP GPS device for the Jupiter
21. In Test BIT The receiver can be commanded to execute a BIT at any time while in Navman binary mode The receiver performs the test and returns the results in the corresponding output message A BIT is commanded by sending a binary perform built in test command message Message 1300 Such a command will interrupt normal receiver operations and result in a system reset Output messages that are processed by the serial I O hardware when the BIT command is received are output but subsequent output messages are suspended until after the BIT cycle is complete When the BIT is complete the receiver is reset and normal operation resumes This means that the BIT results may not be the first received output message after a BIT command 4 7 5 1 Interpreting BIT results A device failure indicator in the BIT results message is valid for all devices installed on the board The failure words defined in Message 1100 will be zero if the device is working as expected and non zero if an error was detected ROM failure The ROM Failure word in Message 1100 indicates the result of a ROM program memory checksum test A failed status means that the ROM chip may be defective RAM failure The RAM failure word in Message 1100 indicates the results of a non destructive pattern test and an address line integrity test A failed status means that the RAM chip s may be defective EEPROM failure There are no explicit tests of the EEPROM
22. Inchauspe Argentina 15 148 136 90 MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 83 Canton Astro 1966 Phoenix Islands Cape South Africa Cape Canaveral Bahamas Florida Carthage Tunisia Chatham Island Astro 1971 New Zealand Chatham Island Chua Astro Paraguay Corrego Alegre Brazil Dabola Guinea Djakarta Batavia Indonesia Sumatra DOS 1968 New Georgia Islands Gizo Island Easter Island 1967 Easter Island European 1950 MEAN FOR Austria Belgium Denmark Finland France West Germany Gibraltar Greece Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland European 1950 MEAN FOR Austria Denmark France West Germany Netherlands Switzerland European 1950 MEAN FOR Iraq Israel Jordan Lebanon Kuwait Saudi Arabia Syria European 1950 Cyprus European 1950 Egypt European 1950 England Channel Islands Ireland Scotland Shetland Islands European 1950 Finland Norway European 1950 Greece European 1950 Iran European 1950 Italy Sardinia European 1950 Italy Sicily European 1950 Malta European 1950 Portugal Spain European 1979 MEAN FOR Austria Finland Netherlands Norway Spain Sweden Switzerland Fort Thomas 1955 Nevis St Kitts Leeward Islands Ga
23. Nieves European 1979 Gandajika Base Pitcairn Astro 1967 Provisional South Chilean 1963 Geodetic Datum 1949 Provisional South American 1956 Guam 1963 Puerto Rico GUX 1 Astro Qatar National Hjorsey 1955 Qornoq Hong Kong 1963 Rome 1940 Indian Thailand Santa Braz Indian Bangladesh Santo DOS Ireland 1965 Sapper Hill ISTS 073 Astro 1969 South American 1969 Johnston Island 1962 South Asia Kandawala Southeast Base Kerguelen Island Southwest Base Kertau 1948 Timbalai 1948 La Reunion Tokyo L C 5 Astro Tristan Astro 1968 Liberia 1964 Viti Levu 1916 Luzon Wake Eniwetok 1960 Table E 1 NavCore datums maintained and selectable through the LABMON development software MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 88 APPENDIX F 2 x 10 pin field connector information This appendix contains ordering information for the 2 x 10 pin field connector Note The Pico modules have a different 2 x 10 pin field connector to the one described below Please see the appropriate data sheet for details PCB sockets 3M part number 20way 150220 6002 TB Digikey part number 3M1020 ND IDC ribbon cable sockets AMP Tyco part number 20w 111626 4 Digikey part number ASA20K ND APPENDIX G RG 142 and RG 316 Specifications T
24. Transistor Transistor Logic Two dimensional coverage hours the number of hours per day with three or more satellites visible Three visible satellites can be used to determine location if the GPS receiver is designed to accept an external altitude input Altitude Hold Two dimensional navigation Navigation mode in which a fixed value of altitude is used for one or more position calculations while horizontal 2D position can vary freely based on satellite range measurements UDRE User Differential Range Error A measure of error in range measurement to each satellite as Seen by the receiver UERE User Equivalent Range Error Update Rate the GPS receiver specification which indicates the solution rate provided by the receiver when operating normally U S Air Force Space Command the U S Air Force agency responsible for the operation of the GPS Space and Control Segments UTC Universal Time Coordinated This time System uses the second defined true angular rotation of the Earth measured as if the Earth rotated about its conventional terrestrial pole However UTC is adjusted only in increments of one second The time zone of UTC is that of Greenwich Mean Time GMT VCO Voltage Controlled Oscillator VDOP Vertical Dilution of Precision A measure of how much the geometry of the satellites affects the position estimate computed from the satellite range measurements in the vertical perpendicular to the plane of
25. U Uy U user position e Cg user clock bias Figure C 2 Range processing equations GPS system operation MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 77 One range this sphere measurement puts us somewhere on Two range measurements put us somewhere on this circle Three measurements put us at one of two points of which only one is a reasonable solution Figure C 3 Satellite ranging intersections Similar equations are then used to calculate velocity using relative velocities instead of pseudo ranges The position velocity and time data is generally computed once a second If one of these parameters such as altitude is known only three satellite pseudo range measurements are needed for the receiver to determine its position and time In this case only three satellites need to be tracked GPS accuracy GPS accuracy has a statistical distribution which is dependent on two important factors The expected accuracy will vary with the error in the range measurements as well as the geometry or relative positions of the satellites and the user Dilution of precision The Geometric Dilution of Precision GDOP indicates how much the geometric relationship of the tracked satellites affects the estimate of the receiver s position velocity and time Four other DOP components indicate how the geometry specifi
26. availability and the required frequency search range the number of Doppler bins for each satellite 4 5 3 Data collection Sub frame data collection is a continuous process once a satellite is in track This technique guarantees that current ephemeris and almanac information are always available to an operating GPS receiver making identification of unhealthy satellites easy 4 5 3 1 Ephemeris Ephemeris data is gathered and maintained on a per satellite basis For continuously tracked satellites no blockage it will take between 18 and 36 seconds to gather the data set Once gathered itis used to compute high accuracy satellite position velocity and acceleration PVA states for navigation and re acquisition processes Note that this data is only maintained in SRAM due to its limited time validity 4 5 3 2 Almanac Almanac data is gathered and maintained on a per satellite basis For continuously tracked satellites no blockage it will take a minimum of 12 5 minutes to gather the complete data set for all satellites The primary function of almanac data is to provide approximate satellite PVA states for the acquisition process Note that this data is maintained in EEPROM due to its validity over an extended time range weeks 4 5 3 3 UTC and ionospheric corrections This data is gathered and maintained independently of the satellite from which it was obtained one set is used for all For continuously tracked sat
27. called a pseudo range instead of a true range PSF Post Select Filter PVT Position velocity and time RAM Random Access Memory Receiver channels a GPS receiver specification which indicates the number of independent hardware signal processing channels included in the receiver design RF Radio Frequency RFI Radio Frequency Interference ROM Read Only Memory RTC Real Time Clock MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 74 RTCA Radio Technical Commission for Aeronautics RTCM Radio Technical Commission for Maritime Services SA Selective Availability The method used by the DoD to control access to the full accuracy achievable with the C A code Satellite elevation the angle of the satellite above the horizon SEP Spherical Error Probable The radius of a sphere centred at the user s true location that contains 50 percent of the individual three dimensional position measurements made using a particular navigation system Sequential Receiver a GPS receiver in which the number of satellite signals to be tracked exceeds the number of available hardware channels Sequential receivers periodically reassign hardware channels to particular satellite signals in a predetermined sequence SNR Signal To Noise Ratio expressed in decibels SOG Speed Over Ground SPS Standard Positioning Service A position
28. d The 32768 sum value must be treated as a special case since it cannot be negated NOTE A CURRENT BUG CAUSES CHECKSUM ERRORS FOR A VALUE OF ZERO or 32 768 3 2 6 Log request messages Figure 3 2 shows the format of the data portion of standard log request messages The ranges for words 6 7 and 8 of these messages are as follows Trigger 0 on time 1 on update Interval 0 to 65535 seconds an interval of zero produces a query as if the query bit Q in word 4 of the message header has been set Offset relative to the next even minute zero to 60 seconds An offset of zero specifies an initial output relative to the current time an offset of 60 specifies an initial output seconds into the next minute When the Trigger field is set to on time integer value 0 the first output will occur at the next offset seconds into the minute and will repeat every interval seconds thereafter When the trigger field is set to on update the specified message will be output only when the data is updated e g when satellite almanac is collected 3 3 Binary message data The data portion of a binary message if it exists can be variable in length as specified by the data word count found in the header The data checksum follows the data and is not included in the data word count The data checksum is a 16 bit word used to validate the data portion of the message It is transmitted as the last word of a
29. decimal seconds hhmm ss ss 222435 LAT Latitude 1111 11 3339 7334 LAT REF Latitude direction N 7 north S 7 south a N LON Longitude yyyyy yy 11751 7598 LON REF Longitude direction E east W west a GPS QUAL GPS quality indicator Note 2 NUM SATS Number of satellites in use 00 to 12 INIIAI l gt HDOP Horizontal dilution of precision o ALT_MSL GEOID_SEP Antenna altitude above below mean sea level geoid Note 3 Units of antenna altitude metres Geoidal separation Note 4 M Units of geoidal separation metres DGPS AGE Age of differential GPS data Note 5 STA ID Differential reference station ID 0000 to 1023 Note 6 0000 CKSUM Checksum 41 lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Note 1 When the navigation solution is invalid fields 1 to 5 and 8 to 14 are null Field 7 also has special meaning see Note 3 Note 2 GPS quality indicator 0 fix not available or invalid 1 GPS fix 2 DGPS fix Note 3 The geodetic altitude can be computed from the mean sea level altitude by adding the geoidal separation word 11 Note 4 Geoidal separation is the difference between the WGS 84 Earth ellipsoid and mean sea level geoid Note 5 Time in seconds since the last SC1 04 Type 1 or Type 9 update null field when DGPS is not used Note 6 This field is null when DG
30. differential corrections even if they are available The DGPS timeout parameter is used to specify the maximum allowable time difference between current time and the validity time of the DGPS corrections If the timeout is exceeded DGPS navigation solutions are unavailable until the correction time delta becomes less than the timeout see sections 4 6 and 4 7 4 3 5 Cold start control A simple control that enables or disables this feature and sets the timeout for automatic transition to cold start is available see section 4 4 for a description of this feature 4 3 6 Solution validity criteria This configuration feature allows the user to specify a set of conditions that must be met for a navigation solution to be reported as valid Constraints that can be imposed on solution validity include use of DGPS corrections use of altitude minimum number of satellites maximum expected position errors EHPE and EVPE See section 4 6 for a description of this feature 4 3 7 User entered altitude This configuration feature allows the user to supply a known value of altitude that can be used to improve the overall quality of the navigation solution The most common application of this feature is to provide a mean sea level value for a boat that is used exclusively on an ocean see section 4 6 4 3 8 Vehicle platform select This configuration feature allows the user to specify the type of vehicle in which the Jupiter receiver
31. header is shown in Figure 3 1 3 2 1 Message header word 1 Each input output message starts with a synchronisation word of the form 0x81FFyex with DEL 255 decimal occupying the first eight bits followed by the Start Of Header SOH 129 decimal occupying the second eight bits of the synchronisation word 3 2 2 Message header word 2 Word 2 contains the numeric message ID For example word 2 for Message ID 1000 would be High Byte Low Byte 0000 0011 1110 1000 MSB LSB MSB LSB or OxO3E8 ex 3 2 3 Message header word 3 Word 3 contains the word count for the data portion of the message The word count does not include the data checksum word A zero data word count indicates a header only message 3 2 4 Message header word 4 The fourth word of the message header is a 16 bit field allocated to protocol and message related flags These flag bits extend control over ACK NAK requests and implement message logging requests The zero s represented in the word 4 field shown in Figure 3 1 are reserved bits and should be set to zero within this word The ACK NAK control mechanism gives the user the ability to request either ACK or NAK or both independently for each message request The user sets the request R bit and either the acknowledge A bit or negative acknowledge N bit or both to select the proper acknowledge behaviour With this approach the user can configure requests only to be NAKed alerting the user
32. in seconds Table 3 16 Message 1117 power management duty cycle in use MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 26 3 5 1 13 Message 1130 serial port communication parameters in use This message contains the communication parameters for the receiver s two serial ports Message ID 1130 The contents of the serial port communication parameters in use message are described in Table 3 17 Rate Variable Message Length 21 words Word No Name Message header Header checksum Set time Note 1 Sequence number Note 2 10 ms ticks 0 to 4294967 295 0 to 32767 Port 1 commun ication parameters 9 0 1 Port 1 character width Port 1 stop bits Bit 0 7 bits 1 7 8 bits 0 21 122 Port 1 parity 0 7 no parity 1 odd parity 2 even parity Port 1 bps rate Note 3 0 custom 1 300 2 600 3 1200 4 2400 5 4800 6 9600 7 19200 8 38400 9 57600 10 76800 11 115200 Port 1 pre scale Note 3 0 to 255 Port 1 post scale Note 3 0 to 7 Table 3 17 1 of 2 Message 1130 serial port communication parameters in use MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 2f Word No Port 2 communication parame
33. may be null to indicate that the previous setting for the data item should be left unchanged For example reset may be commanded without specifying the other parameters by issuing the following command SPRWIINIT A 5555599595 lt CR gt lt LF gt When using null fields the following restrictions apply If a supplied parameter has a corresponding unit specifier or reference indicator it must also be supplied Both latitude and longitude must be provided to specify a valid horizontal position Both ground speed and heading must be provided to specify a valid horizontal velocity e If a magnetic heading is specified horizontal position lat lon and UTC time and date must also be provided UTC time and date must be provided together Table 3 56 INIT message Navman proprietary receiver initialisation MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 56 3 6 2 4 Navman proprietary protocol message IPRO This proprietary message allows the user to set the message format protocol which will be used to communicate information to and from the receiver through the host serial I O port Currently the available protocols are binary with fixed point numbers and NMEA 0183 Storage for the protocol type parameter requires EEPROM The contents of the IPRO message are described in Table 3 57 Sample message PRWIIPRO RBIN Message ID
34. navigation processing The held altitude disable bit controls the use of stored GPS based altitude to aid the receiver when the vertical geometry deteriorates The ground track smoothing bit controls the use of satellite range bias estimates to minimise the position shifts resulting from SA and constellation changes The position pinning bit controls the use of a horizontal speed test to pin the position reported by the receiver and eliminate the wander associated with SA when static Message ID 1221 Ground track smoothing and position pinning are not used when DGPS corrections are in use The contents of the nav configuration message are described in Table 3 33 3 5 2 12 Message 1300 perform built in test command This message instructs the receiver to immediately execute its Built In Test BIT Results of the BIT are available in the BIT results message The contents of the perform built in test command message are described in Table 3 34 Rate as required maximum rate is 1 Hz Message length 15 words Word No Name Message header Header checksum Sequence number Note 1 Nav configuration word 7 0 0 to 32767 Held altitude disable default enabled nt enabled Ground track smoothing disable default 0 enabled 1 7 disabled 0 enabled 1 7 disabled Bit 7 2 Position pinning disable default enabled 0 enabled 1 disabled 3 Disable low quali
35. range integrated carrier phase and Doppler measurements from the satellites and external altitude inputs if available An eight state Kalman filter estimates position velocity and clock errors The OEM has substantial control over the operation of the navigation system to customise it for a specific application 4 6 1 Geodetic datums Geodetic parameters are used in both input and output messages The receiver reports position as a set of geodetic parameters latitude longitude and altitude in the geodetic position status output message binary Message 1000 Geodetic parameters are also reported in the GPS fix data message NMEA Message GGA with the substitution of Mean Sea Level MSL altitude for geodetic altitude and in the recommended minimum specific GPS data message NMEA Message RMC as latitude longitude The receiver expects geodetic parameters as part of the geodetic position and velocity initialisation input message binary Message 1200 Whether geodetic parameters are used as input or output data they are always referenced to the currently selected geodetic datum Each geodetic datum is defined by five parameters The semi major axis Flattening of the reference ellipsoid Delta X component of the WGS 84 datum origin offset Delta Y component of the WGS 84 datum origin offset Delta Z component of the WGS 84 datum origin offset The receiver has 189 pre defined user datums selectable by the OEM
36. receiver to recognise the message otherwise the message will be ignored Table 3 58 Q message standard query MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 57 4 0 Jupiter GPS receiver operation This section presents a detailed operational description of the Jupiter series of GPS receivers An overview is provided for the navigation and receiver support functions Each of the receiver s internal storage devices are described as well as how each one is initialised and used to control operational configurations This section also provides a description of start up modes and satellite management 4 1 Internal on board data sources Internal data sources are the built in information storage capabilities of the GPS receiver The on board receiver firmware maintains these data sources for use on a continuing basis 4 1 1 Static Random Access Memory SRAM SRAM is used to store all firmware variables manipulated by the GPS receiver If external power has been supplied to SRAM when the main power is disconnected this data will be available to the initialisation functions at start up Satellite ephemeris last position and frequency standard parameters are important data that helps to minimise TTFF if the data is available in SRAM 4 1 2 Real time clock RTC Along with SRAM an on board RTC is a valuable source of data at system start
37. s C 20 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 2 Unique identification of each update This allows a different set of data to be in use while newer data are only stored to EEPROM The issue number is preserved from run to run if non volatile storage is available Note 3 Defines a cubic in T TINF Over a range of TINF 65 degrees C each term can produce from 0 002 to 60 ppm approximately Note 4 TBD These parameters will be used to compensate temperature dynamics transients Note 5 These parameters define the temperature sensor scaling according to the equation T TREF TFILT TO SO Note 6 Defines a linear equation in T TINF Over a range of TINF 65 C each term can produce from 0 002 to 60 ppm approximately Oto 2 22 0 to 22 Sa Table 3 36 Message 1310 frequency standard input parameters MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 42 3 5 2 15 Message 1317 power management control This message controls the use of power management in the receiver The contents of the power management control message are described in Table 3 37 Message ID 1317 Note Message 1317 is primarily used to input key parameters from GPS systems without
38. s ground track and altitude This smoothing is accomplished without any loss of dynamic response However this method is not required and is automatically disabled when DGPS is available Without DGPS the method is enabled by default Most users should leave it enabled One reason for disabling it would be to compare the solution with a point solution from another receiver or a solution calculated off line Ground track smoothing can be disabled using the nav configuration message binary Message 1221 The configuration word is stored in EEPROM so the setting for ground track smoothing will be retained through power off and reset cycles 4 6 4 Solution validity The validity of navigation solution outputs is determined by user defined criteria The OEM can specify which criteria to apply for the particular application There are five possible criteria used to validate a solution 1 Was an altitude measurement used 2 Was DGPS used 3 How many satellite measurements were used 4 What is the Expected Horizontal Position Error EHPE 5 What is the Expected Vertical Position Error EVPE The OEM cannot change the validity criteria in NMEA mode These criteria can be set using only the binary solution validity criteria message Message 1217 and they are retained through power off and reset cycles in EEPROM 4 6 4 1 Altitude measurement validity criterion The altitude measurement validity criterion allows
39. than position differences The worst heading error at 5 m s is 1 1 degrees when SA is off or DGPS is on All heading determination techniques using GPS velocities have large uncertainties at small velocities when the velocity approaches the magnitude of the inherent noise MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 81 APPENDIX E Reference ellipsoids and datum tables for Jupiter and NavCore receivers Reference Ellipsoids The following data is taken from DoD World Geodetic System 1984 DMA TR 8350 2 B 1 Dec 1987 Second Printing Includes 1 Sept 1991 updates REFERENCE ELLIPSOIDS Inverse Flattening No Name Semi Major Axis Airy 6377563 396000 299 324965 Modified Airy 6377340 189000 299 324965 Australian National 6378160 000000 298 250000 Bessel 1841 6377397 155000 299 152813 Clarke 1866 6378206 400000 294 978698 Clarke 1880 6378249 145000 293 465000 Everest 1830 6377276 345000 300 801700 INIIAI N Everest 1948 6377304 063000 300 801700 Fischer 1960 6378166 000000 298 300000 Modified Fischer 1960 6378155 000000 298 300000 Fischer 1968 6378150 000000 298 300000 GRS 1980 6378137 000000 298 257222 Helmert 1906 6378200 000000 298 300000 Hough International Krassovsky 6378270 00000
40. to 1023 MSB 0 to 19 05 270 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 Each value of frequency error in the table shares this common offset value Note 4 Flag to indicate that the offset has been established Note 5 Filtered estimate of accumulated error in the table offset value Note 6 Filtered estimate of the current aging rate Note 7 Whole week number of the last update of the aging rate Note 8 LSB the approximate time of last table entry update MSB the frequency error at each table temperature less the table offset 14 269 Table 3 20 Message 1160 frequency standard table output data MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 31 3 5 1 17 Message 1180 flash boot status This message is output in the Jupiter flash board receiver only at start up to control the flash download process and to report the re
41. to its customers and may be used for informational purposes only Navman assumes no responsibility for errors or omissions in these materials Navman may make changes to specifications and product descriptions at any time without notice Navman makes no commitment to update the information and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to its specifications and product descriptions No license express or implied by estoppel or otherwise to any intellectual property rights is granted by this document Except as provided in Navman s Terms and Conditions of Sale for such products Navman assumes no liability whatsoever THESE MATERIALS ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND EITHER EXPRESSED OR IMPLIED RELAT ING TO SALE AND OR USE OF NAVMAN PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FORA PARTICULAR PURPOSE CONSEQUENTIAL OR INCIDENTAL DAMAGES MERCHANTABILITY OR INFRINGEMENT OF ANY PAT ENT COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT NAVMAN FURTHER DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION TEXT GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS NAVMAN SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT INCIDENTAL OR CONSEQUENTIAL DAMAGES INCLUDING WITHOUT LIMITATION LOST REVENUES OR LOST PROFITS WHICH MAY RESULT FROM THE USE OF THESE MATERIALS Navman products are not intended for use in medical lifesaving or life sustaini
42. up If external power has been applied to the RTC when the main power is disconnected time date information will be available to the initialisation functions at start up Valid time date is a key component used to compute satellite visibility and to minimise TTFF Note A value of last known time is available in SRAM On the Jupiter board the RTC is powered whenever SRAM is powered see section 4 7 for more information about the RTC 4 1 3 Electrically Erasable Programmable Read Only Memory EEPROM On board EEPROM is useful for long term storage of data that varies somewhat over time but is in general fairly constant over short periods of time weeks Unlike SRAM and the RTC power is not required to maintain data during idle states Important data in EEPROM that helps to minimise TIFF includes satellite almanac last known position and frequency standard parameters Note EEPROM is used only if the required data is not available from SRAM see section 4 7 for more information about the EEPROM 4 1 4 Read Only Memory ROM On board ROM is only used as a data source if SRAM and EEPROM are unavailable Satellite almanac and frequency standard parameters can be obtained from ROM with limited usefulness 4 2 Initialisation 4 2 1 Definition Initialisation is defined as the set of data or actions that provide time varying information for use by the GPS receiver at start up The most common example is Position Velo
43. varying of the position estimate while the receiver is static is undesirable for users who display their position on a map or for those with similar applications The receiver s proprietary navigation software is capable of pinning the position output when the estimated velocity is low and the navigation solution is of good quality This prevents the varying behaviour of the solution in static situations but introduces some risk that actual platform motion will be mistaken for deliberate SA induced error By default the position pinning feature of the Jupiter GPS receiver is enabled The OEM can turn it off using the nav configuration message binary Message 1221 4 6 3 5 Ground track smoothing Without the use of DGPS satellite measurements are corrupted by SA and do not generate a consistent estimate for receiver position Typical range errors are on the order of 30 m The receiver processes all satellites above the mask angle to minimise the effects of the range error Changes occur in the set of satellites being processed because of blockage and the rising and setting of satellites When a change occurs the position estimate formed from averaging these errors is shifted These shifts can be substantial typically 10 m to 20 m but up to 100 m or more in bad geometry The receiver has a proprietary compensation technique for these constellation switch effects which maintains a smooth estimate of the platform
44. when a problem arises without incurring the overhead necessary to continuously process ACKs The lower six bits of the flags word can be used as an additional input identifier This identifier is not explicitly processed by the receiver it is echoed back in the same location as part of the header in ACK NAK responses This feature allows the user to uniquely distinguish which input message an acknowledgement corresponds to when multiple input messages with the same message ID were processed during a particular period of time The flags word now supports message logging requests The connect C and disconnect D bits are used to enable and disable respectively message outputs and can be used either independently or in conjunction with the log request bits A header only message with a message ID and the connect bit set enables the specified message with existing timing characteristics Likewise a header only message with message ID and the disconnect bit set disables the specified message Trigger on time on update Word 6 Interval sec Word 7 Of set sec Word 8 Data Checksum Word 9 Figure 3 2 Standard log request message format data portion A message with both connect and disconnect bits is ignored Note that enabling and disabling a message does not modify its timing characteristics trigger interval or offset A log request with the connect bit set will set up the message s timing charact
45. 0 6378388 000000 6378245 000000 297 000000 297 000000 298 300000 South American 1969 6378160 000000 298 250000 WGS 60 6378165 000000 298 300000 WGS 66 6378145 000000 298 250000 WGS72 6378135 000000 298 260000 WGS 84 6378137 000000 298 257224 Bessel 1841 Namibia 6377483 865000 299 152813 Everest 1956 6377301 243000 300 801700 Everest 1969 6377295 664000 300 801700 Everest Sabah amp Sarawak 6377298 556000 300 801700 SGS 85 6378136 000000 298 257000 MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice The following lists of datums maintained and selectable through the LABMON development software apply to Navman s Jupiter Series of GPS receivers ROM Datums Code Name EI dx dy dz 0 WGS 84 Default 21 0 0 0 Adindan MEAN FOR Ethiopia Sudan 6 166 15 204 2 Adindan Burkina Faso 6 118 14 218 3 Adindan Cameroon 6 134 2 210 4 Adindan Ethiopia 6 165 11 206 5 Adindan Mali 6 123 20 220 6 Adindan Senegal 6 128 18 224 7 Adindan Sudan 6 161 14 205 8 Afgooye Somalia 16 43 163 45 9 Ain el Abd 1970 Bahrain 15 150 251 2 10 Ain el Abd 19
46. 3 8 ASCII 0 to 255 Integer 16 32 768 to 32767 Double integer 32 2 147 483648 to 2 147 483647 Triple integer 140 737 488 355328 to 48 140737 488 355 327 0 to 65535 0 to 4294 967 295 0 to 281 474976 710656 Note 1 The term word is used throughout this document to specify a quantity which occupies 16 bits of storage Note 2 Data items using bit storage are specified with a format of wb where w is the word number and b is the bit number 0 15 0 LSB within the word Multiple bit items bit fields are indicated by a range of word bit values e g 8 4 8 7 Note 3 Although the AAMP2 processor and C compiler use 16 bit character representations this data interface will use the more common 8 bit representation The Jupiter receiver software will pack unpack the character data internally as needed Unsigned integer 1 16 Unsigned double integer UDI 2 32 Unsigned triple integer UTI 3 48 Table 3 1 Binary message data type MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 8 High Byte Low Byte 1000 0001 1111 1111 Word 1 MSB LSB MSB LSB Figure 3 1 Binary message header format 3 2 Binary message header The binary message header format has been modified slightly from the NavCore V format to accommodate message logging requests The format of the new message
47. 3 Bit 1 disabled 9 7 Jamming detection enabled Bit 1 enabled 9 8 Active antenna Bit 1 active 0 passive C No threshold 0 to 50 10 Cold start time out UI S 0 to 32767 11 DGPS correction time out UI S 0 to 32767 12 Elevation mask rad 0 to n 2 Selected cand idates 13 0 14 15 Selected candidate Note 4 Bit 1 included candidate Solution validity cri teria 15 20 15 0 15 1 Attitude not used Differential GPS Bit 1 required 1 required 15 2 DR measurement 1 required 15 3 GPS calibration 1 required 15 4 GPS only 1 required 155 15 15 Reserved 16 Number of satellites in track required 0 to 12 17 18 Minimum expected horizontal error 0 to 1000 19 20 Minimum expected vertical error 0 to 1000 Application platform 0 default 1 static 2 pedestrian 3 marine lakes 4 marine sea level 5 land auto 6 air 22 Data checksum Note 1 Set time is an internal 10 ms T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but provides sequence of events knowledge The T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count tha
48. 400 bps along with a data link protocol preamble parity and even error correction bits This would be stripped off at the receiver end and the differential correction bits would be stored in the buffer to be transferred to the receiver at will DGPS broadcasts intended for general public use require that the data link be a standard published design For non public use however the reference station data link and receivers could be part of an integrated DGPS system In such a case the data might be encrypted to limit the service to paying customers The format allows for such operation At the minimum rate of 50 bps there is considerable robustness in the data link The corrections are broadcast frequently enough so that the loss of as many as three consecutive corrections can be tolerated and still provide 5 m accuracy GPS receiver LEE ev measurement dag processor navigation data position coordinates display and output differential data processor E ul Data link MELLE LE E E data link receiver demodulator data formatter Eh ee ee ee Se Ss SS Figure C 5 User equipment block diagram MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 80 APPENDIX D Frequently Asked Questions FAQ This appendix provides answers to frequently asked questions about GPS in general and
49. 6 Sequence number Note 1 l 0 to 32767 Initialisation Control 7 0 7 15 7 0 Force time Bit E normal 1 forced 7 1 GPS time valid Bit 1 valid 7 2 UTC time valid Bit 1 valid 7 3 Lat lon valid Bit 1 valid 74 Altitude Valid Bit 1 valid K Speed course valid Bit 1 valid 7 6 Magnetic course Bit 1 magnetic 7 7 Climb rate valid Bit 1 valid 7 8 7 15 Reserved 8 GPS week number UI weeks 0 to 32767 9 10 GPS seconds into week UDI S 0 to 604799 11 UTC day UI days 1 to 31 12 UTC month UI months 1 to 12 13 UTC year UI years 1980 to 2079 14 UTC hours UI h 0 to 23 15 UTC minutes UI min 0 to 59 16 UTC seconds UI S 0 to 59 17 18 Latitude DI rad 0 to r 2 10 19 20 Longitude DI rad 0 tom 10 21 22 Altitude DI m 0 to 50000 10 23 24 Ground speed UI m s 0 to 1000 10 25 Course UI rad 0 to 2r 10 26 Climb rate i m s 300 10 27 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Table 3 23 Message 1200 geodetic position and velocity initialisation MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 33 3 5 2 2 Message 1210 user defined datum This message allows the user to define a datum to be used by the receiver to transform its position solution Up to five user defined datums may be stored Storage of these paramete
50. 70 Saudi Arabia 15 143 236 7 11 Anna 1 Astro 1965 Cocos Islands 3 491 22 435 12 Antigua Island Astro 1943 Antigua Leeward Islands 6 270 13 62 43 zc EE e Lesotho Malawi Swaziland 6 443 on 204 14 Arc 1950 Botswana 6 138 105 289 15 Arc 1950 Burundi 6 153 5 292 16 Arc 1950 Lesotho 6 125 108 295 17 Arc 1950 Malawi 6 161 73 317 18 Arc 1950 Swaziland 6 134 105 295 19 Arc 1950 Zaire 6 169 19 278 20 Arc 1950 Zambia 6 147 74 283 21 Arc 1950 Zimbabwe 6 142 96 293 22 Arc 1960 MEAN FOR Kenya Tanzania 6 160 6 302 23 Ascension Island 1958 Ascension Island 15 191 103 51 24 Astro Beacon E 1945 lwo Jima 15 145 75 272 25 Astro DOS 71 4 St Helena Island 15 320 550 494 26 Astro Tern Island FRIG 1961 Tern Island 15 114 116 333 27 Astronomical Station 1952 Marcus Island 15 124 234 25 28 Australian Geodetic 1966 Australia amp Tasmania 3 133 48 148 29 Australian Geodetic 1984 Australia amp Tasmania 3 134 48 149 30 Ayabelle Lighthouse Djibouti 6 79 129 145 31 Bellevue IGN Efate amp Erromango Islands 15 127 769 472 32 Bermuda 1957 Bermuda 5 73 213 296 33 Bissau Guinea Bissau 15 173 253 27 34 Bogota Observatory Colombia 15 307 304 318 35 Bukit Rimpah Indonesia Bangka amp Belitung Islands 4 384 664 48 36 Camp Area Astro Antarctica McMurdo Camp Area 15 104 129 239 37 Campo
51. Appendix A Acronyms abbreviations and glossary 72 Appendix B Refe rencBs isis te teas taa esas eener 76 APPENDIX C NAVSTAR GPS operation ecseseeeeeeeee 76 APPENDIX D Frequently Asked Questions FAQ 81 APPENDIX E Reference ellipsoids and datum tables for Jupiter and NavCore receiverS A 82 APPENDIX F 2 x 10 pin field connector information 89 APPENDIX G RG 142 and RG 316 Specifications 89 Typical Specification for RG 3165 ccccccseeseeeeeee eee eeeeeeeeeneeneeneaeeeseeeeeeeeaseseeneeseaneeseeseeees 89 Electrical Characteristics noreste tenente ke Exe idee ee deben qon chess Rn Ee eadein 89 ll Physical CharacteristiCS uiii irre ccn EE aevo eed aarti ahaa 89 measurement le 80 ditferentiali data PROCESSORS EE EE 80 MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice Features The Jupiter series of GPS receivers offers the following physical operational and support features OEM product development that is fully supported through application s engineering compact GPS receiver footprint 12 parallel satellite tracking channels supports NMEA 0183 data protocol
52. C periodically while the system is in its Kalman filter navigation mode 4 7 4 Differential GPS DGPS DGPS techniques can be used to eliminate errors introduced by Selective Availability SA and other error sources DGPS requires one GPS receiver to be located at a precisely surveyed location This receiver often referred to as a base station or reference station calculates corrections to the measured pseudo range and delta range measurements from each of the satellites it is tracking These corrections are then broadcast over a communications link to remote GPS receivers in the field which apply these corrections to their Navigation data last known position solution validity criteria frequency standard data user entered altitude selected datum almanac data platform class cold start control satellite elevation Mask Angle satellite candidate List differential GPS control default serial output messages user defined datums navigation control Table 4 2 Parameters and data maintained in EEPROM MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 68 measurements before computing a position solution This technique effectively eliminates much of the error due to SA as well as errors due to unmodelled satellite clock errors satellite ephemeris errors and atmospheric delays
53. Held altitude the altitude value that will be sent to the Kalman filter as a measurement when in Altitude Hold Mode It is an Auto Hold Altitude unless an Amended Altitude is supplied by the application processor HDOP Horizontal Dilution of Precision Hz Hertz IF Intermediate Frequency IGRF International Geomagnetic Reference Field 1 0 Input output IODE Issue Of Data Ephemeris JPO Joint Program Office An office within the U S Air Force Systems Command Space Systems Division The JPO is responsible for managing the development and production aspects of the GPS system and is staffed by representatives from each branch of the U S Military the U S Department of Transportation Defense Mapping Agency NATO member nations and Australia Kalman Filter Sequential estimation filter which combines measurements of satellite range and range rate to determine the position velocity and time at the GPS receiver antenna MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 73 km Kilometre L1 Band the 1575 42 MHz GPS carrier frequency which contains the C A code P code and navigation messages used by commercial GPS receivers L2 Band a secondary GPS carrier containing only P code used primarily to calculate signal delays caused by the ionosphere The L2 frequency is 1227 60 MHz LD LR Line Driver Line Receiver LED Light Emi
54. Jupiter GPS receiver module Designer s guide 11 12 T Pico Pico T series Related products Jupiter 11 low power Development kit TU10 D007 051 Jupiter 11 standard 5 V Development kit TU10 D007 061 Jupiter 11 dead reckoning Development kit TU10 D007 101 Jupiter 12 standard Development kit TU10 D007 351 Jupiter 12 dead reckoning DR Development kit TU10 D007 352 Jupiter Pico standard Development kit TU10 D007 361 Jupiter Pico timing Development kit TU10 D007 363 Related documents Jupiter T e Product brief LA010039 Data sheet LA010050 Jupiter 12 Product brief LA010040 e Data sheet LA010065 Jupiter Pico and Pico T e Product brief LA010041 Data sheet LA010066 Data sheet LA010093 Jupiter series T 12 Pico Pico T Development kit Quick start guide LA010088 Development kit Guide LA010089 DR receiver Gyro application note LA010090 MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice Contents e 5 RT e Dt d E 6 1 1 Product overvleuw 6 EN RR Tele 6 11 2 Receiver architecture oen c Eee ient eese hades oh Maen eines 6 2 0 Hardware interface me T 8 3 0 Serial data I O te E 8 3 1 Binary message format and word structure eene 8 34 1 Binary message e TT 8 SR SA o feine 8 3 2 Bina
55. Length 20 words Word No Name Message header Header checksum Sequence number Note 1 l 0 to 32767 Port control validity data Port 1 data valid Bit 1 data valid Port 2 data valid Bit 1 data valid Reserved Port 1 character width UI 0 7 bits 1 8 bits Port 1 stop bits UI 0 1 1 2 0 no parity Port 1 parity UI 1 odd parity 2 7 even parity 0 custom 1 300 2 600 3 1200 4 2400 5 4800 6 9600 7 19200 8 38400 9 57600 10 76800 11 115200 Port 1 pre scale Note 2 0 to 255 Port 1 post scale Note 2 0 to 7 Port 2 character width i 0 7 bits 1 8 bits Port 2 stop bits i 021 122 0 no parity Port 2 parity i 1 odd parity 2 even parity 0 custom 12300 2 600 3 1200 4 2400 5 4800 6 9600 7 19200 8 38400 9 57600 10 76800 11 115200 Port 2 pre scale Note 2 0 to 255 Port 2 post scale Note 2 0 to 7 Note 1 The sequence number is a count that indicates if the data in a particular binary message has been updated or changed since the last message input Note 2 Pre scale post scale parameters are used to set custom bps rates bps rate CPU clock 16 x pre scale x 2post scale Port 1 bits per second bps Rate Port 2 bps rate Table 3 38 Message 1330 serial port communication parameters MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change with
56. MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 71 Appendix A Acronyms abbreviations and glossary This appendix provides a list of all acronyms abbreviations and selected terms used in this document together with their associated meaning 2D Two Dimensional 2Drms Two Dimensional root mean square 3D Three Dimensional 3Drms Three Dimensional root mean square AAMP Advanced Architecture Micro Processor A D Analog Digital Almanac a set of orbital parameters that allows calculation of approximate GPS satellite positions and velocities The almanac is used by a GPS receiver to determine satellite visibility and as an aid during acquisition of GPS satellite signals The almanac is a subset of satellite ephemeris data and is updated weekly by GPS Control Altitude hold a technique that allows navigation using measurements from three GPS satellites plus an independent value of altitude Altitude hold enable command this message allows the application processor to enable or disable the altitude hold feature Altitude hold mode a navigation mode during which a value of altitude is processed by the Kalman filter as if it were a range measurement from a satellite at the Earth s centre WGS 84 reference ellipsoid centre AP Application Processor The processor connected to the Jupiter GPS receiver port which controls the rece
57. N002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 25 3 5 1 12 Message 1117 power management duty power management duty cycle in use message cycle in use are described in Table 3 16 This message controls the use of power management in the receiver The contents of the Message ID 1117 Rate Variable Message Length 10 words Word No Resolution Message header Header checksum Set time Note 1 10 ms ticks O to 4294967295 Sequence number Note 2 0 to 32767 0 off 1to4 on Power management on duty cycle Note 3 10 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 In power management mode the RF power may be switched off to reduce power consumption The digital circuitry may be gated off and the processor idled when not needed This field gives the measurement engine permission to turn off the RF for the minimum off time
58. Naparima BWI Trinidad amp Tobago North American 1927 MEAN FOR Antigua Barbados Barbuda Caicos Islands Cuba Dominican Republic Grand Cayman Jamaica Turks Islands North American 1927 MEAN FOR Belize Costa Rica El Salvador Guatemala Honduras Nicaragua North American 1927 MEAN FOR Canada North American 1927 MEAN FOR CONUS North American 1927 MEAN FOR CONUS East of Mississippi River including Louisiana Missouri Minnesota North American 1927 MEAN FOR CONUS West of Mississippi River North American 1927 Alaska North American 1927 Bahamas Except San Salvador Island North American 1927 Bahamas San Salvador Island MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 85 North American 1927 Canada Alberta British Columbia North American 1927 Canada Manitoba Ontario North American 1927 Canada New Brunswick Newfoundland Nova Scotia Quebec North American 1927 Canada Northwest Territories Saskatchewan North American 1927 Canada Yukon North American 1927 Canal Zone North American 1927 Cuba North American 1927 Greenland Hayes Peninsula North American 1927 Mexico North American 1983 Alaska Canada CONUS North American 1983 Central America Mexico Observatorio Metreeo 1939 Azores Corvo amp Bores Islands Old Egyptian 1907 Egypt O
59. PS is not used Table 3 47 GGA message GPS fix data MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 49 5 6 1 4 GPS satellites active and DOP GSA This message contains the Jupiter receiver s operating mode satellites used for navigation and DOP values The contents of the GSA message are described in Table 3 48 Sample message GPGSA A 3 04 16 09 24 3 33 1 96 2 70 06 3 6 1 5 GPS satellites in view GSV This message contains the number of satellites in view PRN numbers elevation azimuth Message ID GSA and Signal to Noise Ratio SNR values Each transmission identifies up to four satellites max additional satellite data is sent in a second or third message The total number of messages being transmitted and the number of the message being transmitted is indicated in the first two fields The contents of the GSV message are described in Table 3 49 Sample message GPGSV 2 1 07 24 60 216 50 20 47 135 47 12 40 020 47 16 36 319 46 75 Rate variable Fields 17 Field No GSA Field description Start of sentence and address field Field type Example GPGSA OP MODE Mode Note 1 A FIX MODE _ Mode Note 2 3 SATN PRNs of satellites used in solution null for unused fields 04 16 09 24 PDOP Position dilution of precision Note 3 3 33 HDOP
60. These datums together with their identification codes are listed in Appendix E of this document All of the pre defined datums are taken from the US Government document Department of Defense World Geodetic System 1984 4 6 1 1 User selection of geodetic datums The default datum is WGS 84 defined as datum code zero for the receiver Other datums are selected using the Map Datum Select message binary Message 1211 The selected code is reported back in the position status output message 1000 or 1001 For example if the receiver was in Navman binary mode and the OEM wanted to use a previously recorded position to initialise the receiver and then get reported positions in WGS 84 the OEM would send three messages to the receiver as follows 1 Send a map datum select message binary message 1211 with the desired datum code the new datum code is reported back in message 1000 and or 1001 if either or both messages have been enabled 2 Send a geodetic position and velocity initialisation message binary Message 1200 with the correct latitude longitude and altitude 3 Finally send another message 1211 with the datum code 0 to set the datum back to WGS 84 The selected datum is always stored in EEPROM so that it is saved during power off and reset cycles The Navman binary Map Datum Select message must be used to change the geodetic datum the datum cannot be changed when in NMEA mode NMEA outputs will use t
61. This improved solution is present in all output messages With a few minor exceptions outlined below DGPS is enabled by default but may be disabled by the OEM Because SA changes with time the corrections deteriorate with time as well Therefore DGPS operation will only occur when enough current DGPS corrections are available The Jupiter receiver accepts RTCM SC 104 format DGPS correction messages directly on the auxiliary serial port The receiver also accepts DGPS corrections data formatted as a binary data input message Message 1351 over its primary serial port Detailed information on the format of this message is provided in Section 3 5 2 19 4 7 4 1 The RTCM protocol The Jupiter will accept 6 of 8 RTCM SC 104 data directly from the auxiliary serial port No external formatting is required and the receiver handles all parsing and verification of the data The user needs only to verify the integrity of the data sent to the receiver to ensure that high bit errors are not present in the detected RTCM raw data stream The user should be aware that RTCM SC 104 data will be used only if for every 30 bit word the syndrome 6 bit parity exactly matches the one which should occur on the basis of the 24 bit data seen in each word No attempt will be made to correct single bit errors any syndrome mismatch will cause rejection of that data word and rejection of the message in which it exists The receiver will parse the
62. a over the air availability means that the user does not normally have to supply almanac data 4 2 5 Universal Time Coordinated UTC and ionospheric parameters UTC and ionospheric correction parameters are available from every tracked satellite broadcast once every 12 5 minutes and are maintained in the on board EEPROM and SRAM Like almanac and ephemeris data over the air availability means that the user does not normally have to supply UTC and ionospheric data MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 58 4 3 Configuration 4 3 1 Definition Configuration is defined as the set of data or actions that provide information that is fairly constant and usually connected with installation environmental or user preferences Common examples are map datums or satellite elevation mask angle Configuration data customises or optimises the GPS receiver for use in a particular situation In general this data is held constant until the user decides to change it Table 4 1 provides a brief description of all default configuration parameters Configuration data controls how the receiver works on a daily basis Typically this information is stored in EEPROM accessed at the time of initialisation and updated whenever the user dictates a change The obvious benefit of this feature is that the board can be configured to work in a customised wa
63. about the Jupiter series of GPS receivers it is intended to supplement the operational description provided in section 4 0 of this document 1 How far and under what conditions can a passive antenna track before it is necessary to change it to an active antenna There is no simple answer to this question Navman generally recommends limiting cable loss to 3 dB between the antenna and the receiver board If attenuation exceeds this value there may be degraded signal acquisition and navigation accuracy performance GPS satellites transmit more power than their specification requires but that margin is allocated to the 3 dB cable loss The safest approach is to use an active antenna unless the antenna and receiver engine are co located 2 Can the Jupiter receiver operate efficiently in an urban location with tall structures and buildings Yes By using 12 parallel channels Jupiter receivers maintain continuous tracking of all visible satellites and produce an over determined solution minimising the effects of signal blockage and giving optimal performance in dense urban environments 3 Is there any danger to the receiver when switching is done between active and passive antennas Yes If pre amp power is supplied to an active antenna and then connected to a passive antenna there is a high probability of damage since the passive antenna often presents a short circuit to ground at DC This then shorts out the pre amp power line and d
64. andard table input data This message allows the user to input the parameters and table data used in the receiver s frequency standard compensation model It is intended that this message will be used in conjunction with message 1160 to retrieve and restore this information for external storage The Message ID 1360 contents of the frequency standard table input data message are described in Table 3 42 3 5 2 21 Message 1380 flash reprogram This message is used only in the Jupiter flash board to force the receiver into the re program flash mode The contents of the flash re program message are described in Table 3 43 Rate As required maximum rate 1 Hz Message Length 268 words Word No Name Resolution Message header Header checksum Sequence number Note 1 0 to 32767 Table frequency offset Note 2 0 to 51 Table frequency offset valid Note 3 1 valid Reserved 9 Offset error estimate Note 4 ppm 0 to 51 10 Aging rate estimate Note 5 ppm yr 0 to 5 11 last rate update week Note 6 weeks 0 to 32767 Frequency standard table Note 7 12 267 LSB MSB weeks 0 to 1023 ppm 0 to 19 05 0 15 268 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 2 Each value of frequenc
65. ata This navigation data which is computed and controlled by the GPS Control Segment includes the satellite s time its clock correction and ephemeris parameters almanacs and health status for all GPS satellites From this information the user computes the satellite s precise position and clock offset Currently the DoD encrypts the P code ranging signal and thus denies access to the Precise Positioning Service PPS by unauthorised users The Standard Positioning Service SPS uses the C A code ranging signal and is intended for general public use The control segment This segment consists of a master control station located in Colorado Springs and a number of monitor stations at various locations around the world Each monitor station tracks all the GPS satellites in view and passes the signal measurement data back to the master control station where computations are performed to determine precise satellite ephemeris and satellite clock errors The master control station generates the upload of user navigation data for each satellite This data is subsequently re broadcast by the satellite as part of its navigation data message The user segment This segment is the collection of all GPS receivers and their application support equipment such MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 76 as antennas and processors This equipm
66. avman binary operation 9600 8 N 1 When de asserted the normal operational state configuration and initialisation data are obtained from all valid sources SRAM EEPROM RTC etc 4 4 Start up modes Jupiter GPS receivers have four types of start up modes warm initialised cold and frozen based on the availability and source of initialisation data Each of these modes are briefly described in the following paragraphs 4 4 1 Warm start This state is present when all key data PVT ephemeris and frequency standard parameters is valid and available in SRAM Two common conditions that result in this state are a software reset hot start after continuous navigation or a return from an idle period power cycle of a few minutes that was preceded by a period of continuous navigation 4 4 2 Initialised start This state is similar to warm start except that ephemeris data is not available at start up implying that SRAM was not powered during the idle state or that the data time validity has expired Common conditions that result in this state are user supplied PVT initialisation or continuous RTC operation with an accurate last known position available from EEPROM 4 4 3 Cold start This state occurs as a result of unknown position and or time either of which causes an unreliable satellite visibility list Almanac information is MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary infor
67. c hh hhmmss ss 1111 11 x and yyyyy yy Numeric value fields Variable numbers Variable length integer or floating point numeric field optional leading and trailing zeros Note The decimal point and associated decimal fraction are optional if full resolution is not required eg 73 10 73 1 073 1 73 Fixed HEX field Variable text Fixed length HEX numbers only most significant bit on the left Variable length valid character field Fixed alpha field Fixed length field of uppercase or lowercase alpha characters Fixed number field Fixed length field of numeric characters Fixed text field Fixed length field of valid characters Note 1 Spaces may only be used in variable text fields Note 2 A negative sign or 2DHEX is the first character in a field if the value is negative The sign is omitted if the value is positive Note 3 All data fields are delimited by a comma Note 4 Null fields are indicated by no data between two delimiters Table 3 3 NMEA field type summary MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 12 Output message name Message ID Input message name Message ID Geodetic position status output Geodetic position and velocity initialisation Channel summary User defined datum definition
68. cally affects errors in horizontal position HDOP vertical position VDOP position PDOP and time TDOP DOPs are computed based on the spatial relationships of the lines of sight between the satellites and the user The motion of the satellites relative to each other and the user causes the DOPs to vary constantly For the same range measurement errors lower DOPs relate to more accurate estimates The errors in the range measurements used to solve for position may be magnified by poor geometry The least amount of error results when the lines of sight have the greatest angular separation between them see Figure C 4 For example if two lines of sight are necessary to establish a user position the least amount of error is present when the lines cross at right angles of of M d p B M A Good DOP Figure C 4 Geometric dilution of precision Range Measurement Error The error in the range measurement is dependent on one of two levels of GPS accuracy to which the user has access PPS is the most accurate but is MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 78 reserved for use by the DoD and certain authorised users SPS is less accurate and intended for general public use This is the level of accuracy used by the Jupiter family of GPS receivers The SPS signal can be intentionally degraded to a certain extent by a process
69. city and Time PVT initialisation For a GPS receiver installed in an automobile this information is constantly changing as time progresses and the vehicle moves from location to location Initialisation data is required when the on board data sources are old or invalid Serial input messages are prepared by the user and transmitted to the GPS receiver In general the GPS receiver is capable of bootstrapping itself without any valid data sources but TTFF times are extended 4 2 2 Position Velocity Time PVT data The most common form of user supplied initialisation data is position and time velocity is normally included in this group but it is only required for higher dynamic operations Accurate PVT and valid almanac ephemeris data are required to generate the current satellite visibility list and appropriate acquisition uncertainties resulting in optimal TTFF performance 4 2 3 Satellite ephemeris Unlike user PVT information satellite ephemeris data is available from every satellite that is continuously tracked 18 seconds minimum collection time The ephemeris is maintained in SRAM This over the air availability means that the user does not normally have to supply ephemeris data 4 2 4 Satellite almanac Almanac information for all satellites is available from each tracked satellite 12 5 minute collection time for the complete set and is maintained in the on board EEPROM and SRAM Like ephemeris dat
70. d Note 2 Approved sentence formatter of the data being RMC ENABLE Output enable flag A enable V disable Note 3 TRIG Output trigger t on time u on update Note 4 INTERVAL CKSUM Checksum optional Output interval Seconds 0 once Note 4 OFFSET Initial output offset seconds from minute mark Note 4 X X hh lt CR gt lt IF gt Sentence terminator lt CR gt lt IF gt Note 1 NMEA message prefix P proprietary message indicator RWI Navman Systems Inc mnemonic ILOG log control message ID Note 2 A special form of this field disables all output messages Use as the message ID as in the following example PRWIILOG V Note 3 This field may be null to indicate that the previous setting should be left unchanged Note 4 The TRIG INTERVAL and OFFSET fields may be null to indicate that the previous setting should be left unchanged Table 3 55 ILOG message Navman proprietary log control MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 55 3 6 2 3 Navman proprietary receiver initialisation message INIT This proprietary message commands the Jupiter receiver to perform a reset modify its operating are described in Table 3 56 Sample message PRWIINIT V 3339 650 N 11751 680 W 64 131 mode or reinitialise itself using specified paramete
71. d digits of degrees two fixed digits of minutes and a variable number of digits for decimal fraction of minutes Note Leading zeros always included for degrees and minutes to maintain fixed length the decimal point and associated decimal fraction are optional if full resolution is not required Longitude yyyyy yy Fixed variable length field degrees minutes decimal three fixed digits of degrees two fixed digits of minutes and a variable number of digits for decimal fraction of minutes Note Leading zeros always included for degrees and minutes to maintain fixed length the decimal point and associated decimal fraction are optional if full resolution is not required Time hhmmss ss Fixed variable length field hours minutes seconds decimal two fixed digits of hours two fixed digits of minutes two fixed digits of seconds and a variable number of digits for decimal fraction of seconds Note Leading zeros always included for hours minutes and seconds to maintain fixed length the decimal point and associated decimal fraction are optional if full resolution is not required Defined field Some fields are specified to contain pre defined constants most often alpha characters Such a field is indicated in the NMEA 0183 standard by the presence of one or more valid characters The following characters and character strings used to indicate field types are excluded from the list of allowable characters A a
72. d the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 The satellite measurement sequence number relates the position solution data to a particular set of satellite measurements found in binary Messages 1002 and 1007 channel summary message and channel measurement message respectively Note 4 The value of this data item was initially set using the solution validity criteria message Message 1217 Note 5 Either no DR messages are being received or data has been detected as inconsistent with GPS Note 6 No calibration is available for DR measurements from concurrent GPS or from stored values Note 7 No calibration is available for DR measurements from concurrent GPS Note 8 It should be noted that bit zero of word 11 does not refer to a solution propagated by the navigation software This bit is used to indicate if the solution was propagated by the serial I O manager to generate a 1 Hz output message when no new navigation state data was available This is an error condition potentially caused by a shortage of throughput in one cycle It is unlikely to occur and is s
73. device in response to message 1100 However the receiver maintains and reports a status of what parameters have been written to EEPROM When a data block has been written and cannot be successfully read back from the device a failure will be reported A failure will also be reported if the device does not respond to an attempt to MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 70 access it A failed status means that the EEPROM chip may be defective Digital Signal Processor DSP The DSP failure word in message 1100 indicates the results of the DSP tests A failed status indicates that one or more of the DSP tests failed and that the DSP chip may be defective RTC The RTC failure word in message 1100 indicates the results of a time rollover test of the RTC A failed status indicates that the RTC test failed and that the RTC chip may be defective PORT 1 host port and PORT 2 aux port error and received byte counts There are no explicit tests for the two serial communications ports However a count of bytes received with error and a count of bytes received without error for each port are maintained and reported in Message 1100 These words provide a measure of the reliability of the communications interface If the count of bytes received with error is large the interface may be defective or the port configuration may be incorrect
74. e Note 1 10 ms ticks 0 to 4294 967 295 Sequence number Note 2 0 to 32767 Satellite measurement sequence number Note 3 0 to 32767 Channel measurement data 10 12 j Pseudo range Note 4 TI 1 4 13 12 j Pseudo range rate DI 21 474 836 15 12 j Carrier phase TI 1 4 18 12 j Carrier phase bias TI 1 4 21 12 j Phase bias count 0 to 65535 154 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 The satellite measurement sequence number relates the position solution data to a particular set of satellite measurements found in binary Messages 1002 and 1007 channel summary message and channel measurement message respectively Note 4 j 0 to 11 Table 3 9 Message 1007 channel measurement MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 19 3 5 1 6 Message 1009 reduced ECEF position 12 channels The content
75. e 1108 UTC time mark pulse output MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 24 3 5 1 11 Message 1110 frequency standard Note Message 1110 is primarily used to output key parameters in use parameters to GPS systems without non volatile This message outputs the parameters used to storage This is why the format of input Message support the receiver s uncompensated crystal 1310 is exactly the same the output message is oscillator The contents of the frequency standard used to capture data while the input message is parameters in use message are described in used to restore data Table 3 15 Message ID 1110 Rate variable Message length 22 words Word No i Resolution Message header Header checksum Set time Note 1 10 ms ticks 0 to 4294967295 Sequence number Note 2 l 0 to 32767 Frequency standard issue number Note 3 UI 0 to 65535 Temperature characteristic CO aging and calibration offset Note 4 s s 0 to 24 C1 linear term Note 4 s s C 0 to 2 C2 second order term Note 4 s s C 0 to 275 l l C3 third order term Note 4 s s C 0 to 2 TINF inflection point Note 4 C 0 to 100 Temperature dynamics DO Note 5 l D1 Note 5 Temperature sensor calibration TREF calibration reference temperature Note 6 0 to 100 TO temperature
76. e 2 0 to 32767 Satellite measurement sequence number Note 3 GPS week number 0 to 32767 GPS seconds into week 0 to 604 799 13 14 GPS nanoseconds from epoch UDI 0 to 999999 999 Channel summary data Measurement used Note 4 Bit 1 used 0 to 32767 15 0 3 n 15 1 3 n 15 2 3 15 3 3 DGPS corrections available Bit 1 available 16 3 n Satellite PRN UI 0 to 32 17 3 n C No UI dBHz 0 to 60 51 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 The satellite measurement sequence number relates the position solution data to a particular set of satellite measurements found in binary Messages 1002 and 1007 channel summary message and channel measurement message respectively Note 4 n 0 to 11 Ephemeris available Bit 1 available Measurement valid Bit 1 valid n n Table 3 6 Message 1002 channel summary MN002000A 2004 Navman NZ Ltd All rights reserved Prop
77. e 35 3 5 2 5 Message 1213 satellite candidate select eene 35 3 5 2 6 Message 1214 DGPS control c iere cre UR Ree Leu eoe sonne Vua EUROS 36 3 5 2 7 Message 1216 Cold Start control J iret iot s eo ain d esta odd 36 3 5 2 8 Message 1217 solution validity Input 37 3 5 2 9 Message 1219 user entered altitude input sene 38 3 5 2 10 Message 1220 application platform control eene 39 3 5 2 11 Message 1221 nav tee EE 40 3 5 2 12 Message 1300 perform built in test command see 40 MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 3 5 2 13 Message 1303 restart command cc sccccscescserscccecensontccendesntenssedestueesesenaetteseberteeensense 41 3 5 2 14 Message 1310 frequency standard input parameters sene 42 3 5 2 15 Message 1317 power management control sse 43 3 5 2 16 Message 1330 serial port communication parameters seen 44 3 5 2 17 Message 1331 message protocol control s irae 45 3 5 2 18 Message 1350 factory calibration mput eene 45 3 5 2 19 Message 1351 raw DGPS RTCM SC 104 data 46 3 5 2 20 Message 1360 frequency standard table input data sess 47 3 5 2 21 Message 1380 flash reprogram 11er tier oret destina task ege 47 3 6 Jupiter NMEA data messag
78. e U S Government document which contains the official policy on the commercial use of GPS GaAs Gallium Arsenide GDOP Geometric Dilution of Precision A factor used to describe the effect of the satellite geometry on the position and time accuracy of the GPS receiver solution The lower the value of the GDOP parameter the less the error in the position solution Related indicators include PDOP HDOP TDOP and VDOP GMT Greenwich Mean Time GPS Global Positioning System A space based radio positioning system which provides suitably equipped users with accurate position velocity and time data When fully operational GPS will provide this data free of direct user charge worldwide continuously and under all weather conditions The GPS constellation will consist of 24 orbiting satellites four equally spaced around each of six different orbital planes GPSRE GPS Receiver Engine GPS Time the number of seconds since Saturday Sunday midnight UTC with time zero being this midnight Used with GPS week to determine a specific point in GPS time GPS Week the number of weeks since January 6 1980 with week zero being the week of January 6 1980 Used with GPS Time to determine a specific point in GPS time HDOP Horizontal Dilution of Precision A measure of how much the geometry of the satellites affects the position estimate computed from the satellite range measurements in the horizontal East North plane
79. e is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 0 user mode exception 1 exec mode exception 2 trap 3 executive error 4 executive Service Routine error 5 user error Table 3 22 Message 1190 error status MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 32 3 5 2 Binary input message descriptions This section provides details for each of the input binary messages 3 5 2 1 Message 1200 geodetic position and velocity initialisation This message allows the user to initialise the receiver with the specified geodetic position ground speed course over ground and climb Message ID 1200 rate The course may be either true or magnetic as indicated by the magnetic course field The GPS UTC time represents the time at which the solution was computed and if present will be used to propagate the solution to the current time The contents of the geodetic position and velocity initialisation message are described in Table 3 23 Rate as required maximum rate is 1 Hz Message length 27 words Word No Name Type Units Range Resolution 1 4 Message header 5 Header checksum
80. e mark output event 3 4 1 NMEA output messages The following supported NMEA output messages comply with the NMEA 0183 version 2 01 standard GGA GPS fix data GSA GPS DOP and active satellites GSV GPS satellites in view MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 10 RMC recommended minimum specific GPS data The Jupiter receiver also supports the following Navman proprietary output messages BIT built In test results ERR error status RID receiver ID ZCH Jupiter channel status These Navman proprietary messages conform to the message format described below 3 4 2 NMEA input messages The Jupiter receiver supports the following proprietary input messages IBIT built in test command Navman proprietary ILOG log control Navman proprietary INIT receiver initialisation Navman proprietary IPRO protocol Navman proprietary The INIT message is used to command initialisation of the receiver and the IPRO message is used to change the message protocol The first character of the message sentence is P followed by a three character mnemonic code for Navman Systems Inc RWI according to Appendix III of the NMEA 0183 standard 3 4 3 NMEA message format All NMEA 0183 data messages are in ASCII form Each message begins with ASCII 24 2 and ends with ASCII CR lt LF gt ODyex and OAyex The valid character se
81. e platform class is stored in EEPROM so it is retained when power is turned off 4 6 2 1 Pedestrian This platform class is used when the receiver is mobile in a low dynamic environment An example would be a hand held GPS receiver used for hiking 4 6 2 2 Automotive This platform class is for moderate dynamic environments where altitude is not constant A common example would be a car truck or motorcycle 4 6 2 3 Aircraft This platform class is for high dynamic environments where altitude may change rapidly 4 6 3 Navigation cycle The navigation software nominally executes once per second During each execution the navigation state is propagated forward to the current time and updated with any available measurements The navigation solution is then provided to the serial interface for output in the selected message set either Navman binary or NMEA Note NMEA may be slightly delayed compared to the binary data 4 6 3 1 State propagation User state propagation over the measurement update interval nominally one second is by dead reckoning with constant tangent plane velocity The tangent plane is defined by the current position and the selected datum This means that if the vertical velocity is zero the state propagation will be at constant altitude in the user selected datum For Pedestrian Automotive and Aircraft platforms user state propagation is in three dimensions Once the receiver has been navigating a
82. e using a particular navigation system Clock error the uncompensated difference between synchronous GPS system time and time best known within the GPS receiver CMOS Complimentary Metal Oxide Semiconductor C No Carrier to Noise density ratio Also Channel Signal To Noise COG Course Over Ground Cold start a condition in which the GPS receiver can arrive at a navigation solution without initial position time current ephemeris and almanac data Control segment the master control station and the globally dispersed monitor stations used to manage the GPS satellites determine their precise orbital parameters and synchronise their clocks dB Decibel DB 9 9 pin D subminiature connector DB 25 25 pin D subminiature connector dBiC Decibel isotropic Circular measure of power relative to an isotropic antenna with circular polarisation dBm Decibel milliwatt measure of power relative to one milliwatt dBW Decibel Watt measure of power relative to one watt DC Direct Current DGPS Differential GPS A technique to improve MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 72 GPS accuracy that uses pseudo range errors recorded at a known location to improve the measurements made by other GPS receivers within the same general geographic area DI Double Precision Integer Doppler aiding a signal processing strate
83. ect to change without notice 6 2 The Scorpio device which contains an architecture that might be used to integrate a integral microprocessor and all GPS specific particular Jupiter receiver with an application signal processing hardware processor that drives peripheral devices such as a In addition memory and other supporting display and keyboard The interface between the components configure the receiver into a complete application s processor and the Jupiter receiver is navigation system Figure 1 3 illustrates an through the serial data interface CX74051 CX11577 receiver front end baseband processor RF connector signal samples serial port 2 GDGPS data i RTCMSC 104 OEM host interface clock signals serial port 1 down converter A D control pre select L timing reference filter 12 channel GPS 10 949 MHz correlator post select Xtal filter serial SRAM EEPROM row e r iid contains 0 software 32 kHz Xtal regulated DC power 3 3 or 5 0 VDC input EMI filtering amp power supply bat backup to SRAM amp RTC 3 3 or 5 0 VDC bat backup Figure 1 2 Internal Jupiter architecture GPS antenna pre amplifier optional Jupiter GPS receiver DGPS optional power gh F power communications interface supp OEM display application processor Figure 1 3 Possible Jupiter OEM architecture MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary infor
84. ection user defined datums platform class communication parameters etc simply receiving new inputs is all that is required for the data to be refreshed in the EEPROM In the case of slowly changing data position almanac frequency standard data etc additional constraints of distance moved change in value and or elapsed time are imposed on the EEPROM Configuration data Serial port configuration both ports Satellite management parameters UTC and ionosphere model parameters update The various parameters and data maintained in the Jupiter receivers EEPROM are listed in Table 4 2 4 7 3 RTC services The RTC services provide for the storage of time date data maintained while the system is in an idle state As long as external power is provided to the RTC device it will keep the time date data current providing the system with accurate time initialisation as needed The time date data is only read from the RTC during system initialisation When the time date data is stored in the RTC a snapshot of the data is stored with a checksum in the RAM space of the RTC device RTC RAM The snapshot data in the RTC RAM is used to determine if the RTC was kept alive and therefore if the time date data is valid If the clock data is not valid at system initialisation the last known time stored in SRAM will be used if it is available otherwise time will be invalid The time date data is updated in the RT
85. eie Prae eT datu testae ero ga 18 3 5 1 5 Message 1007 channel measurement seien ette tht nene eiie Ea euis 19 3 5 1 6 Message 1009 reduced ECEF position status output seee 20 3 5 1 7 Message 1011 receiver 1D orienter intento re Eo RE nue S nS SEE NUR ERR eae coated 21 3 5 1 8 Message 1012 user settings outpult esee enin tiana ariaa 22 3 5 1 9 Message 1100 built in test results cec ntt tea tritt nnno 23 3 5 1 10 Message 1108 UTC time mark pulse output sse 24 3 5 1 11 Message 1110 frequency standard parameters in Usel 25 3 5 1 12 Message 1117 power management duty cycle in use see 26 3 5 1 13 Message 1130 serial port communication parameters in use 27 3 5 1 14 Message 1135 EEPROM Update gd ce eei EE deg 29 3 5 1 15 Message 1136 EEPROM status 30 3 5 1 16 Message 1160 frequency standard table output data sss 31 3 5 1 17 Message 1180 flash boot status isiin 32 3 0 1 18 Message 1190 eeler 32 3 5 2 Binary input message descriptions sss eme emen 33 3 5 2 1 Message 1200 geodetic position and velocity initialisation ssssssssss 33 3 5 2 2 Message 1210 user defined datum erret ieee teed ien neun 34 3 5 2 3 Message 1211 map datum select norisei aA uneven th seb aka dna 34 3 5 2 4 Message 1212 satellite elevation mask control se
86. elf correcting Normal state propagation which occurs within the navigation software with or without measurements available for processing does not cause this bit to be set Note 9 Navigation is based on GPS alone Current system or GPS DR with no DR measurements available Note 10 DR is running with concurrent calibration by GPS Note 11 DR is running with calibration from stored values from prior operating session Note 12 An uncertainty value of Ox7FFF indicates unknown heading A message value 0x000D indicates Polar navigation equals true and heading uncertainty SD equals 0 06 hex value 0x000C Note 13 Appendix B contains map datum codes from 0 to 188 Codes 300 to 304 are user defined Note 14 The data displayed by this field is not valid until the receiver is in navigation mode Table 3 5 2 of 2 Message 1000 geodetic position status output MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 15 3 5 1 2 Message 1002 channel summary information on a per channel basis The contents This message provides a summary form of the of the channel summary message are described satellite range measurements and signal tracking in Table 3 6 Message ID 1002 Rate Variable defaults to 1 Hz Message Length 51 words Word No Message header Header checksum Set time Note 1 10 ms ticks 0 to 4294967 295 Sequence number Not
87. ellites no blockage it will take a minimum of 12 5 minutes to gather an updated data set UTC corrections are used to compute the exact time offset between GPS and UTC time lonospheric corrections are used by the navigation process to compensate for the effects of the satellite signal passing through the Earth s ionosphere Note that this data is maintained in EEPROM due to its validity over an extended time range a few weeks MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 62 Compute Visible Satellite List Ordered From Highest to Lowest Elevation Angle SVO SV n Determine Required Doppler Bins For SV i E Hardware Channel Available Assign Hardware Channel to Search Specific Doppler Bin SVO Doppler Bins Fully Assigned All Visible Satellites In Track End Search Process Figure 4 1 Jupiter search process MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 63 4 6 Navigation This section describes the operation of the navigation software in the GPS receiver It defines many of the features of the navigation system with emphasis on those that the OEM can control The navigation software initialises and maintains a state vector which is used to report time position and velocity to the user The navigation software uses pseudo
88. ent allows users to receive decode and process the information necessary to obtain accurate position velocity and timing measurements This data is used by the receiver s support equipment for specific application requirements GPS supports a wide variety of applications including navigation surveying and time transfer Receivers may be used in a stand alone mode or integrated with other systems to enhance the overall system performance GPS System operation How A GPS Receiver Determines Position A GPS receiver determines its geographic position by measuring the ranges the distance between a satellite with known coordinates in space and the receiver s antenna of several satellites and computing the geometric intersection of these ranges To determine a range the receiver measures the time required for the GPS signal to travel from the satellite to the receiver antenna The timing code generated by each satellite is compared to an identical code generated by the receiver The receiver s code is shifted until it matches the satellite Ss code The resulting time shift is multiplied DT1 Time signals Pseudo ranges Jon R CDt R cot R cot R pseudo range i 1 2 3 4 C speed of light by the speed of light to arrive at the apparent range measurement Since the resulting range measurement contains propagation delays due to atmospheric effects and satellite and receiver clock errors it i
89. equired maximum rate is 1 Hz Message length 13 words Word No Name Resolution Message header Header checksum Sequence number Note 1 0 to 32767 Altitude not used i 1 required 7 1 Differential GPS i 1 required 7 2 DR measurements required Note 2 i 1 required Concurrent GPS calibration of DR required Note 3 74 GPS only solution required Note 4 i 1 required 7 5 7 15 Reserved 8 Minimum number of satellites used UI 0 to 12 7 3 1 required 9 10 Maximum expected horizontal position error UDI 0 to 1000 10 11 12 Maximum expected vertical position error UDI 0 to 1000 10 13 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 2 Must operate with DR stand alone GPS not acceptable Note 3 DR must be calibrated by concurrent GPS Stored calibration from past sessions not acceptable Note 4 DR must NOT be used even if available Table 3 30 Message 1217 solution validity input MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 37 3 5 2 9 Message 1219 user entered altitude input entry of mean sea level altitude A standard This message allows the user to enter an altitude deviation can be specified to indicate the to be used for altitude
90. eristics and then enable the message Similarly for a combined log and disable request the message will be disabled after the timing characteristics are set To disable all messages set the message ID to FFFFuex all bits set and set the disconnect D bit Setting the query Q request bit will output the message specified by the message ID one time MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 9 during the next output interval Standard log requests will be accepted if the log L bit is set and if the required data parameters are present in the data portion of the request message 3 2 5 Message header word 5 Word 5 of the message header is the data checksum used to validate the header portion of the message It is computed by summing modulo 216 all words including the word containing DEL and SOH contained in the header and then performing a two s complement on the sum SUM Mod 2195 word i The computation of the header checksum may be expressed mathematically as if sum 32768 header checksum SUM else header checksum SUM where a Unary negation is computed as the two s complement of a 16 bit data word b Mod 216 indicates the least 16 bits of an arithmetic process That is carry bits from bit position 16 are ignored c The summation is the algebraic binary sum of the words indicated by the subscript i
91. erto Rico Virgin Islands Qatar National Qatar Qornoq Greenland South Reunion Mascarene Islands Rome 1940 Italy Sardinia Santo DOS 1965 Espirito Santo Island Sao Braz Azores Sao Miguel Santa Maria Islands Sapper Hill 1943 East Falkland Island Schwarzeck Namibia Selvagem Grande Salvage Islands SGS 85 Soviet Geodetic System 1985 South American 1969 MEAN FOR Argentina Bolivia Brazil Chile Colombia Ecuador Guyana Paraguay Peru Trinidad amp Tobago Venezuela South American 1969 Argentina South American 1969 Bolivia South American 1969 Brazil South American 1969 Chile South American 1969 Colombia South American 1969 Ecuador South American 1969 Ecuador Baltra Galapagos South American 1969 Guyana South American 1969 Paraguay South American 1969 Peru South American 1969 Trinidad amp Tobago South American 1969 Venezuela South Asia Singapore Tananarive Observatory 1925 Madagascar Timbalai 1948 Brunei East Malaysia Sabah Sarawak Tokyo MEAN FOR Japan Korea Okinawa Tokyo Japan Tokyo Korea Tokyo Okinawa 182 Tristan Astro 1968 Tristan da Cunha 15 632 438 609 183 Viti Levu 1916 Fiji Viti Levu Island 6 51 391 36 184 Wake Eniwetok 1960 Marshall Islands 14 102 52 38
92. es esee nnne nennen nnne nn nennen nnn nennen 48 3 6 1 NMEA output message descriptions eee nnns 48 3 6 1 1 Navman proprietary Built In Test BIT results sse 48 3 6 1 2 Navman proprietary error status ERR 49 3 6 1 3 GPS EE EE 49 5 6 1 4 GPS satellites active and DOP GSA ssis siusis inian 50 3 6 1 5 GPS satellites in VIOW GSV EEN 50 3 6 1 6 Navman proprietary receiver ID ID 51 3 6 1 7 Recommended minimum specific GPS data RMO seen 52 3 6 1 8 Course over ground and ground speed VTG sss eene 53 3 6 1 9 Navman proprietary Jupiter channel status ZCH seen 54 3 6 2 NMEA input message descriptions ssssssese eene eene nnns 55 3 6 2 1 Navman proprietary built in test command message IBIT esses 55 3 6 2 2 Navman proprietary log control essage ILOG se enne 55 3 6 2 3 Navman proprietary receiver initialisation message INIT sess 56 3 6 2 4 Navman proprietary protocol message IPRO senes 57 3 6 2 5 Standard Query message Q oiii ete ede iex ud ders edad do aa dae 57 4 0 Jupiter GPS receiver operation eeeeeeeeeeeeeeeerreeeee 58 4 1 Internal on board data sources eeeeeeeeeeeeeeneen nennen nnne nnn nnns 58 4 1 1 Static Random Access Memory GRAM eee eene enne nnne nnne 58 4 1 2 Real time clock R IG
93. escriptions This section provides details for each of the input NMEA messages 3 6 2 1 Navman proprietary built in test command message IBIT This proprietary message instructs the receiver to immediately execute its BIT Results of the BIT are available in the Navman proprietary BIT results message The data field is reserved and should be left null The contents of the IBIT message are described in Table 3 54 Sample message PRWIIBIT 3 6 2 2 Navman proprietary log control essage ILOG This proprietary message controls the output of the Jupiter receiver s NMEA messages The contents of the ILOG message are described in Table 3 55 Sample message PRWIILOG RMC A T 5 0 Message ID IBIT Rate as required Fields 1 Field No Symbol PRWIIBIT RES Reserved Field description Start of sentence and address field Note 1 Field type Example PRWIIBIT CKSUM Checksum optional hh lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Note 1 NMEA message prefix P Proprietary message indicator RWI Navman Systems Inc mnemonic ILOG BIT command message ID Table 3 54 IBIT message Navman proprietary BIT command Message ID ILOG Rate as required Fields 5 Field No Symbol Field description Field type Example PRWILOG Start of sentence and address field Note 1 PRWILOG MSGJD requeste
94. estart each time it are described in Table 3 35 is received Message ID 1303 Rate as required maximum rate approximately 0 2 Hz Message length 8 words Word No Name Resolution Message header Header checksum Sequence number Note 1 0 to 32767 Invalidation control 7 0 7 15 7 0 Invalidate RAM Note 2 Bit 0 to 1 TA Invalidate EEPROM Note 3 Bit 0 to 1 7 2 Invalidate RTC Note 4 Bit 0 to 1 7 3 7 14 Reserved 7 15 Force cold start Note 5 Bit 0 to 1 8 Data checksum Note 1 the sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 2 1 invalidate all RAM address space before restart Note 3 1 invalidate all data in the EEPROM device if present before restart Note 4 1 invalidate all data in the RTC device if present before restart Note 5 1 force a cold start reset by clearing RAM and ignoring but not clearing the stored position in EEPROM This provides cold start testing with the valid time If cold start testing without time is desired then the invalidate RTC bit 7 2 should also be set Table 3 35 Message 1303 restart command MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 41 3 5 2 14 Message 1310 frequency standard input parameters This message defines the
95. estroys the bias tee network on the receiver 4 What is the criteria for choosing satellites for navigation if more than four are visible The Jupiter receiver continuously tracks all visible satellites The measurements from these satellites are used in an over determined solution to provide the most robust performance that is possible 5 What is the accuracy of GPS with selective availability turned on How is the accuracy affected by DGPS The U S Government guarantees that horizontal accuracy will be less than 100 m 95 of the time and less than 300 m 99 99 of the time Accuracy with DGPS is primarily a function of the quality and latency of the corrections used 6 What is the difference between the two models for position determination used in GPS WGS 84 and Earth Centred Earth Fixed ECEF ECEF refers to a Cartesian rectangular coordinate system X y Z whose centre is at the middle of the Earth one axis goes through the North Pole one through the Greenwich meridian at the equator and the third passes through the equator 90 degrees offset from the second This System rotates with the Earth GPS satellites broadcast their location in this coordinate system WGS 84 contains a mathematical model of the Earth s surface spheroid which is accepted worldwide However the model does have some limitations For example 0 m altitude may differ from mean sea level in this model by up to 100 m Position in WGS 84 is s
96. format as Type 1 messages but usually only contain corrections for a subset of the visible constellation These messages are typically transmitted at a higher rate than the Type 1 messages Beacons such as those operated by the U S Coast Guard are currently the primary source for these corrections but they are also available from some commercial service providers and base stations 4 7 4 3 Compliance with RTCM SC 104 requirements The Radio Technical Commission for Maritime Services RTCM has a special committee numbered 104 SC 104 Its charter is to create recommended standards for the transmission of DGPS correction data 4 7 4 4 DGPS initialisation and configuration At power on the receiver initialises its internal DGPS database to indicate that no valid DGPS data is available If the user requests the Differential GPS Status message binary Message 1005 the message will indicate that no corrections have been processed Some of the position status messages binary messages 1000 and 1001 and NMEA message GGA will also indicate that the receiver is not computing a DGPS solution As sufficient valid RTCM data is passed to the receiver it will automatically produce DGPS solutions Other than supplying RTCM data and ensuring that DGPS operation is not disabled no action is required on the part of the user to cause DGPS operation The receiver will compute DGPS solutions whenever all of the following conditions are sati
97. gy which uses a measured doppler shift to help a receiver smoothly track the GPS signal to allow a more precise velocity and position measurement DoD Department of Defense DOP Dilution of Precision see GDOP HDOP PDOP TDOP and VDOP DOS Disk Operating System DSP Digital Signal Processor DTR Data Terminal Ready ECEF Earth Centred Earth Fixed A Cartesian coordinate system with its origin located at the centre of the Earth The coordinate system used by GPS to describe three dimensional location For the WGS 84 reference ellipsoid ECEF coordinates have the Z axis aligned with the Earth s spin axis the X axis through the intersection of the prime meridian and the equator and the Y axis is rotated 90 degrees east of the X axis about the Z axis EEPROM Electrically Erasable Programmable Read Only Memory EFP Extended Floating Point EHPE Expected Horizontal Position Error EMC Electromagnetic Compatibility EMI Electromagnetic Interference Ephemeris a set of satellite orbital parameters that is used by a GPS receiver to calculate precise GPS satellite positions and velocities The ephemeris is used to determine the navigation solution and is updated frequently to maintain the accuracy of GPS receivers EPROM Erasable Programmable Read Only Memory ESD Electrostatic Discharge EVPE Expected Vertical Position Error FOM Figure Of Merit FP Floating Point FRP Federal Radio navigation Plan Th
98. h as dense urban centres By continuously tracking all visible GPS satellites and using all of the measurements to produce an over determined and smoothed navigation solution the Jupiter receiver provides a solution that is relatively immune to blockage induced position jumps that can occur in other receivers with fewer channels The 12 channel architecture provides rapid Time To First Fix TTFF under all start up conditions The best TTFF performance is normally achieved when time of day and current position estimates are provided to the receiver However the flexible Jupiter signal acquisition system takes advantage of all available information to provide a rapid TTFF Acquisition is guaranteed under all initialisation conditions as long as available satellites are not obscured To minimise TTFF following a power interruption each of the Jupiter receivers can accept external voltage to maintain power to the Static Random Access Memory SRAM and Real Time Clock RTC for periods following the loss of primary power The use of external voltage assures the shortest possible TTFF following a short power interruption The OEM may extend the operation of the RTC by providing stand by power on a connector pin in which case a short TTFF is achieved by using the RTC time data and prior position data from the receiver s Electrical Eraseable Programmable Read Only Memory EEPROM The Jupiter series supports two dimensional 2D ope
99. has been installed see section 4 6 4 3 9 Navigation control Several navigation control features are provided by the Jupiter GPS receivers These features are groundtrack smoothing position pinning validity criteria See section 4 6 for more details 4 3 10 Configuration straps Configuration straps control the use of available configuration data at the time of initialisation These straps act as metacommands that can override or complement an existing set of configuration data Note These straps are only read once at initialisation time so a power cycle or hardware or software reset must be executed after any strap changes are made 4 3 10 1 National Marine Electronics Association NMEA Select When asserted the host serial communication interface is configured for NMEA operation 4800 8 N l Configuration data related to the host port that may be available from other sources is not used When de asserted operation of the host port is controlled by any available configuration data sources SRAM EEPROM etc Details of the NMEA guarantee that the receiver is started in a known message set are contained in Section 5 0 of this document 4 3 10 2 ROM defaults When asserted all configuration and initialisation data are obtained from ROM defaults In addition SRAM is cleared to guarantee that the receiver is started in a known operational state The host serial communication interface is configured for N
100. hat indicates whether the data in a particular binary message has been updated or changed since the last message input Table 3 28 Message 1214 differential GPS control Message ID 1216 Rate as required maximum rate 1 Hz Message length 9 words Word No Name 1 4 Message header Resolution 5 Header checksum Reserved sequence number 0 to 32767 Cold start disable 1 7 disable Reserved Cold start timeout UI 0 to 32767 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Table 3 29 Message 1216 cold start control MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 36 3 5 2 8 Message 1217 solution validity input status specified in the position output messages The receiver will always output the best position The status will be set to invalid if any of the solution it can attain depending on the number specified requirements are not met Storage of this and quality of available measurements The message s parameters requires EEPROM The Solution Validity Input Message allows the user to contents of the solution validity input message are define the criteria for setting the position validity described in Table 3 30 Message ID 1217 Rate as r
101. he last datum selected in binary mode or WGS 84 if a datum selection has never been made 4 6 1 2 User defined datums Besides the 189 pre defined datums the OEM can define five custom datums for a specific application Each datum is defined by the five parameters described in section 4 6 1 and the new datum definition is sent to the receiver using the User Defined Datum Definition message binary Message 1210 There are five custom datum codes to choose from 300 to 304 All user defined datums are stored in EEPROM Once the datum is stored it is selected using the Navman binary Map Datum Select message in the same manner as the pre defined datums If a custom datum is stored and later re defined the existing datum will be overwritten MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 64 4 6 2 Platform class The Jupiter GPS receiver supports three platform classes pedestrian low dynamics automotive medium dynamics aircraft high dynamics The platform class is set by the OEM to optimise navigation processing for the dynamics of the specific platform that is carrying the receiver The class is used to set process noise parameters velocity decay time constants and speed and altitude limits The default platform class is automotive The OEM sets the platform class using the Application Platform Control message binary Message 1220 Th
102. his appendix provides technical specifications for the RG 316 antenna cable used with the Jupiter GPS receiver Typical Specification for RG 316 L Electrical Characteristics Nominal impedance 50 Q Nominal inductance 0 065 micro h ft Nominal capacitance conductor to shield 29 0 pf ft Nominal velocity of propagation 69 5 Nominal delay 1 48 pf ft Nominal attenuation 1500 Mhz 57 9 dB 100 ft Nominal shield dc resistance at 20 C 6 5 0 1000 ft Nominal conductor dc resistance at 20 C 33 0 0 1000 ft Continuous working voltage 900 V RMS Il Physical Characteristics Nominal weight 10 Ibs 1000 ft Minimum bending radius 1 0 inch Temperature rating 70 to 200 C Type shield and percent coverage silver coated copper Inner braid 9696 Outer braid 9696 Maximum pulling tension 2lbs Insulation material TFE Teflon Jacket material brown tint FEP Teflon Conductor diameter 0 020 inches nominal Core diameter 0 58 inches nominal Outside dimensions 0 96 inches nominal Applicable specifications MIL C 17F M17 113 RG316 Teflon is a trademark of DuPont MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 89 Teflon is a trademark of DuPont 2004 Navman NZ Ltd All Rights Reserved Information in this document is provided in connection with Navman NZ Ltd Navman products These materials are provided by Navman as a service
103. hold during 2D navigation uncertainty associated with the entered altitude If the force use field is not set the receiver may ignore the altitude input if it thinks it has a better The receiver will weight the altitude measurement estimate according to this uncertainty As a special case a zero standard deviation indicates that the quality of Setting the clear field will clear out the last the altitude is not known The contents of the user estimate of altitude which the receiver uses for entered altitude input message are described in altitude hold Setting the MSL select field allows Table 3 31 Message ID 1219 Rate as required maximum rate is 1 Hz Message length 12 words Word No Name Resolution Message header Header checksum Sequence Number Note 1 l 0 to 32767 Altitude input control 7 0 7 Force use Bit 1 force MSL select Bit 1 MSL Store RAM Note 2 Bit 1 store Store EEPROM Note 2 Bit 1 store Clear RAM Bit 1 clear Clear EEPROM Bit 1 clear 8 9 Altitude DI 0 to 50000 10 10 Altitude standard deviation UDI 0 to 10000 10 11 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 2 For an altitude sensor that is supplying data in real time the OEM must ensure that bits 7 2 and 7 3 are set to zero so the attitude value will not be
104. ice 23 3 5 1 10 Message 1108 UTC time mark pulse output 400 milliseconds before the time mark pulse strobe This message provides the UTC seconds into signal The contents of the UTC time mark pulse week associated with the UTC synchronised time output message are described in Table 3 14 mark pulse This message is output approximately Message ID 1108 Rate 1 Hz Message length 20 words Word No Resolution Message header Header checksum Set time Note 1 10 ms ticks 0 to 4294967295 Sequence number Note 2 0 to 32767 UTC time Reserved UTC Seconds Of Week UDI 0 to 604799 GPS to UTC time offset integer 32768 to 32767 part GPS to UTC time offset fractional part UDI ns 0 to 999999999 UTC time validity 19 0 19 15 19 0 Time mark validity Bit 19 1 GPS UTC sync Bit 19 2 19 15 Reserved 20 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Table 3 14 Messag
105. ifications subject to change without notice 79 Occasionally a type 2 message is sent interspersed among the correction messages which provides a secondary correction This is done to allow a user to operate with old up to two hours satellite ephemeris and satellite clock data while the reference station is operating with most recent data This correction called the delta correction is added to the normal correction for that satellite The reference station will usually decode the satellite data before the user does since it is constantly monitoring the data Data Link The data link which communicates the corrections from the reference station to the user receiver can take a number of forms and operate at any of several frequencies The chief requirement is that the messages be communicated reliably at a data rate of at least 50 bps continuous transmission Figure C 5 shows the user data link functions In its simplest form the data link continuously carries the DGPS data message without interruption at a constant data rate of at least 50 bps However it is transparent to the GPS receiver whether the data GPS satellite Krass P e e ee e Ze vg LEM satellite data a uw LL X DGPS data x link v p 99 9 eg mm md is transmitted continuously or in bursts or whether protocol overhead is added For example each message or multiple messages or any fraction of a message could be transmitted as a short burst at 2
106. incoming data bits and decode all of the RTCM SC 104 messages Those messages required for DGPS operation will be used to fill in the DGPS database within the receiver Those messages which are not used will be discarded 4 7 4 2 The RTCM message types The receiver accepts DGPS correction data as a subset of the 64 RTCM SC 104 messages found in Table 4 2 of the RTCM SC 1 04 Version 2 1 standard Though the receiver will accept and decode all RTCM messages not all messages are necessary for DGPS operation The Data Sheet for each of the Jupiter GPS receivers shows which of the messages defined in the RTCM standard are used by the receiver to form a DGPS position solution Refer to the standard for more detailed descriptions of these and other RTCM SC 104 messages Type 1 message Type 1 messages contain pseudo range and pseudo range rate corrections for a complete set of visible satellites Currently this is the most common type of message transmitted by commercial RTCM providers and base stations Type 2 message Type 2 messages contain delta corrections and are transmitted by reference stations to help receivers during ephemeris cutovers These Table 4 2 Parameters And Data Maintained In EEPROM messages are used by the field receiver in conjunction with Type 1 or Type 9 messages until both the reference station and field receiver are operating with the same set of ephemeris Type 9 message Type 9 messages have the same
107. ing service available to all GPS users on a continuous worldwide basis with no direct charge SPS uses the C A code to provide a minimum dynamic and static positioning capability SRAM Static Random Access Memory Stand by SRAM portion of the SRAM that is powered by a keep alive power supply when prime power is removed to preserve important data and allow faster entry into the Navigation Mode when prime power is restored All of the SRAM in the receiver is keep alive SRAM SV Space Vehicle Also Satellite Vehicle TDOP Time Dilution of Precision A measure of how much the geometry of the satellites affects the time estimate computed from the satellite range measurements Three dimensional coverage hours the number of hours per day with four or more satellites visible Four visible satellites are required to determine location and altitude Three dimensional navigation Navigation mode in which altitude and horizontal position are determined from satellite range measurements Time mark pulse a one pulse per second IPPS output synchronised to UTC when the receiver is in its Navigation Mode TOW Time Of Week see GPS time TTFF Time To First Fix The actual time required by a GPS receiver to achieve a position solution This specification will vary with the operating state of the receiver the length of time since the last position fix the location of the last fix and the specific receiver design TTL
108. ing the log control messages supported in both Navman binary and NMEA message protocols Changes to the port configuration settings MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 67 communications protocol and message controls are stored in non volatile EEPROM 4 7 1 2 The auxiliary port The auxiliary port is used exclusively for the receipt of differential corrections in RTCM SC 104 serial message format By default the auxiliary port is configured for 9600 baud no parity 8 data bits and 1 stop bit There is no data output from this port 4 7 2 EEPROM services The EEPROM services provide for the non volatile storage and retrieval of system configuration parameters and data that vary but are generally fairly constant for short periods of time a few weeks The configuration and operational data stored in EEPROM is only read during system initialisation if the complimentary SRAM data is invalid When data is stored in EEPROM a checksum is stored with it to validate the data when it is read If the data read from EEPROM during initialisation is invalid default values from ROM will be used to initialise the system EEPROM data blocks are updated refreshed when the corresponding system data changes significantly The qualification of a significant change varies for each data block In the case of user configurable data items datum sel
109. ion each with its own checksum Each message will have a header but some messages may not have data Message acknowledgements are in the form of a header and message requests are also made using headers Table 3 1 shows the data types used to define the elements of the binary interface messages 3 1 2 Word structure An integer is defined as 16 bits While offsets are incorporated in the message description tables the most convenient specification of memory layout in application implementation is likely to be a structure definition If the item is a fixed point quantity the value of the LSB of the integer is given To convert a fixed point item to a floating point variable the integer representation is floated and multiplied by the resolution When converting to float consideration must be given to the range and resolution of the item to ensure that the type of float selected for the conversion has an adequate mantissa length to preserve the accuracy of the data item Triple word items may require scaling portions of the variable separately and then adding them in floating point form Composite words may have independent definitions for each bit field in the word Flag bits are either zero false or one true All bits that are designated as reserved within the bit descriptions of binary data have undefined values for outputs and must be set to zero for inputs Maximum range Bit Note 2 0 to 1 Character Note
110. ite list is output in the Visible Satellites message binary Message 1003 4 5 1 1 Dilution Of Precision DOP Geometric Dilution of Precision GDOP is a measure of the quality of a satellite constellation geometry GDOP reflects the influence of satellite geometry on the accuracy of user position and time estimates The best geometry is that which produces the lowest GDOP value GDOP acts as a multiplier of the error in position and time estimates due to other sources GDOP is a composite measure It can be separated into Position Dilution of Precision PDOP PDOP reflects the effects of geometry on three dimensional position estimates Time Dilution of Precision TDOP TDOP reflects geometric effects on time estimates The relationship can be expressed as GDOP PDOP TDOP In turn PDOP can be separated into horizontal and vertical components Horizontal Dilution of Precision HDOP Vertical Dilution of Precision VDOP These components represent the effects of satellite geometry on two dimensional horizontal position and on vertical position altitude estimates respectively This relationship can be expressed as PDOP 1 HDOP VDOP The receiver computes the best available GDOP and each of its components in the Visible Satellites message binary Message 1003 The best available GDOP is that associated with the satellite constellation consisting of all visible satellites above the ma
111. iver with command messages and uses data from output messages ASCII American Standard Code for Information Interchange ATO Acquisition Time Out Auto hold The receiver will use the last altitude calculated in 3D navigation as the current value of held altitude when entering altitude hold 2D navigation It will continue to use this value throughout this altitude hold event unless an amended altitude command is received from the application processor The 3D calculated altitude used in this way is called an auto hold altitude B Boolean Baud See bps BIT Built In Test Block satellite satellites designed and built to support GPS development and testing A total of 10 Block satellites were successfully launched between February 1978 and October 1989 Block II satellite satellites designed and built to support GPS Space Segment operation A total of 28 Block II satellites had been built and launched as of August 1995 Block IIR satellite satellites designed to replace Block II satellites bps bits per second sometimes referred to as baud rate C Celsius C A Code Coarse Acquisition Code A spread spectrum direct sequence code that is used primarily by commercial GPS receivers to determine the range to the transmitting GPS satellite CEP Circular Error Probable The radius of a circle centred at the user s true location that contains 50 of the individual position measurements mad
112. known as Selective Availability SA SA is used to limit access to the full accuracy of SPS in the interest of D S national security Differential GPS DGPS Description The following general description of DGPS is from the document RTCM Recommended Standards For Differential NAVSTAR GPS Service Refer to that document for more specific details of DGPS operations see Appendix B Differential operation of the GPS offers the possibility of accuracies from 1 m to 10 m for dynamic navigation applications DGPS operation requires a reference receiver to be placed at a known surveyed in point By comparing the known location with that predicted by the GPS corrections are determined These corrections are then broadcast to nearby users who use them to improve their position solutions Sources of bias error The differential technique works if the main errors are bias errors due to causes outside the receiver This is the case for GPS The major sources of error are the following SA errors artificial errors introduced at the satellites for security reasons Pseudorange errors of this type are about 30 m 1 sigma PPS users have the capability to eliminate them entirely lonospheric delays signal propagation group delay which is typically 20 to 30 m during the day and 3 to 6 m at night Tropospheric delays signal propagation delays caused by the lower atmosphere While the delays are as much as 30 m at low satellite elevati
113. ld Hawaiian MEAN FOR Hawaii Kauai Maui Oahu Old Hawaiian Hawaii 279 183 Old Hawaiian Kauai 5 290 172 Old Hawaiian Maui Old Hawaiian Oahu Oman Oman Ord Survey G Britain 1936 MEAN FOR England Isle of Man Scotland Shetland Islands Wales Ord Survey G Britain 1936 England Ord Survey G Britain 1936 England Isle of Man Wales Ord Survey G Britain 1936 Scotland Shetland Islands Ord Survey G Britain 1936 Wales Pico de las Nieves Canary Islands Pitcairn Astro 1967 Pitcairn Island Point 58 MEAN FOR Burkina Faso amp Niger Pointe Noire 1948 Congo Porto Santo 1936 Porto Santo Madeira Islands Provisional S American 1956 MEAN FOR Bolivia Chile Colombia Ecuador Guyana Peru V Venezuela Provisional S American 1956 Bolivia Provisional S American 1956 Chile Northern Near 19 S Provisional S American 1956 Chile Southern Near 43 S MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 86 Provisional S American 1956 Colombia Provisional S American 1956 Ecuador Provisional S American 1956 Guyana Provisional S American 1956 Peru Provisional S American 1956 Venezuela Provisional S Chilean 1963 Chile South Near 53 S Hito XVIII Puerto Rico Pu
114. lid until cleared from EEPROM Instantaneous altitude is valid for one navigation cycle only This altitude input type is used when there is a continuous source of external altitude data Held altitude Held altitude is stored in the receiver when the navigation solution is valid The held altitude is stored with a variance that grows from the last time it was updated to reflect the age and growing uncertainty of the altitude estimate Use of held altitude is normally a significant performance boost in an urban environment with heavy blockage and it is enabled by default A held altitude value is discarded if the estimated climb rate magnitude exceeds 1 m s The OEM can disable the use of held altitude using the nav configuration message binary Message 1221 4 6 3 4 Position pinning When the receiver is not using DGPS satellite measurements include time varying range errors MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 65 These errors induce velocities in the receiver s state estimate even if the receiver is motionless The magnitude of these velocities depends on the geometry and number of satellites in track Typical values are between one half and two metres per second The position estimate of the receiver will vary within a circle of approximately 100 m the 2Drms position error specified in the GPS SPS Signal Specification This
115. ll grow until they surpass their thresholds and the solution fails the validity test for that reason Some applications require a solution to be marked invalid unless it uses three four or more satellites The OEM can set any of these thresholds by sending a binary solution validity criteria message Message 1217 with the number of satellites required 4 6 4 4 Maximum EHPE validity criterion The EHPE is the one sigma horizontal position error estimate for the solution The validity criterion default is 10 m The meaning of the reported EHPE depends on whether or not DGPS is in use If DGPS is in use the EHPE is the estimated one sigma error in absolute position accuracy When DGPS is not in use the EHPE and EVPE are reported with the effects of the satellite User Equivalent Range Error UERE excluded This excludes SA induced error from the EHPE and EVPE So in SPS navigation the EHPE and EVPE serve as convergence indicators for the Kalman filter not as absolute accuracy limits for the reported position The EHPE validity threshold can be set by the OEM in the binary solution validity criteria message message 1217 4 6 4 5 Maximum EVPE validity criterion The EVPE is the one sigma vertical position error estimate for the solution The default is 25 m The operation and meaning of this criterion is analogous to the EHPE criterion in section 4 6 4 4 The threshold can be set in the binary solution validity criteria
116. llite PRN number and status indication Channel 6 satellite PRN number and status indication Channel 7 satellite PRN number and status indication Channel 8 satellite PRN number and status indication Channel 9 satellite PRN number and status indication Channel 10 satellite PRN number and status indication Channel 11 satellite PRN number and status indication ET Channel 12 satellite PRN number and status indication E CKSUM Checksum hh 37 lt CR gt lt LF gt Sentence terminator Note 1 Channel number xx is implied by position in message Data for all 12 channels is always provided in this message If a channel is unused a value of 0 will appear for both channel fields The status indication hh is a one digit hexadecimal value which represents four bits as follows y O Measurement of the satellite on this channel used in navigation solution lt y 1 gt Ephemeris available for the satellite on this channel lt y 2 gt Satellite on this channel is in track lt y 3 gt DGPS corrections available for the satellite on this channel Note This bit will never be set whenever the configuration of a particular Jupiter GPS receiver does not support DGPS Table 3 53 ZCH message Navman proprietary Jupiter channel status MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 54 3 6 2 NMEA input message d
117. lth j SS RTCM satellite health 1 RTCM source declares satellite bad j 11 Corrections stale 1 received stale corrections j 12 IODE mismatch 1 IODE mismatch j 15 Reserved Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 Only the correction status words for the number of available corrections reported in word 12 of this message are valid Note 4 The word number j ranges from 13 to 24 Table 5 8 Message 1005 DGPS status MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 18 3 5 1 5 Message 1007 channel measurement 12 channels The contents of the channel This message provides measurement and measurement message are described in associated data for each of the receiver s Table 3 9 Message ID 1007 Rate Variable Message Length 154 words Word No Resolution Message header Header checksum Set tim
118. magnetic 271 3 M Magnetic course indicator M SPD_N Speed over the ground knots 0 784 N Nautical speed indicator N knots N SPD_K Speed km 1 452 K Speed indicator K km hr K CKSUM Checksum hh AF lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt INIIAI 055 gt Note 1 Output of this message is temporarily suppressed while the receiver is in acquisition mode Table 3 52 VTG message course over ground and ground speed MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 53 3 6 1 9 Navman proprietary Jupiter channel status ZCH message are described in Table 3 53 ZCH This message complements the GSV message by Sample message providing satellite to channel mapping and a status PRWIZCH 05 F 20 F 04 F 09 F 16 F 06 F 07 6 indication for each channel The contents of the 00 0 24 F 00 0 00 0 00 0 37 Message ID ZCH Rate variable defaults to 1 Hz Fields 24 Field No Symbol Field description Field type Example ZCH Start of sentence and address field PRWIZCH SAT PRN Channel 1 satellite PRN number Note 1 05 STATUS Channel 1 status indication Note 1 F Channel 2 satellite PRN number and status indication Channel 3 satellite PRN number and status indication Channel 4 satellite PRN number and status indication Channel 5 sate
119. mation and specifications subject to change without notice 60 used to identify previously healthy satellites and to generate working visible satellite lists while frequency standard data minimises satellite acquisition uncertainties 4 4 4 Frozen start This state is entered if there are no valid data sources available SRAM RTC EEPROM This is considered to be a recovery mode because EEPROM should always contain valid information An out of the box board or a unit that has not operated for a significant amount of time months may approximate this state because the data in EEPROM may be valid but expired or partially complete 4 5 Satellite management This section describes the satellite management functions of the Jupiter family of GPS receivers 4 5 1 Visible list generation A list of satellites visible to the receiver antenna is maintained whenever possible A satellite is considered visible if its elevation in the sky is known to be above the horizon if its almanac and ephemeris data indicate it is healthy and if it has not been excluded by manual candidate satellite specification Note that although a satellite is visible its measurement is only available for use if the satellite is above the elevation mask angle The receiver s channel resources are directed toward acquiring only those satellites which appear in this list except when the receiver is in cold start mode Satellites within the list are orde
120. mation and specifications subject to change without notice 7 2 0 Hardware interface Details of the specific Jupiter GPS receiver s electrical interface are contained in the applicable data sheet for the receiver the latest Jupiter series data sheets and product briefs can be downloaded from the Navman OEM website at www navman com oem For information about the 2 x I0 pin field connector see Appendix F 3 0 Serial data I O interface This section describes the formats of the two types of messages that can be communicated across the serial data interface for the Jupiter GPS receivers The structure and contents of each binary message are described in section 3 2 The structure and contents of each National Marine Electronics Association NMEA message is described in section 3 3 3 1 Binary message format and word structure 3 1 1 Binary message format The input output binary data stream format is a low byte high byte pattern Each byte is output with its Least Significant Bit LSB first followed by its higher order bits ending with the Most Significant Bit MSB of the data byte The binary message format is almost identical to that used by the previous NavCore MicroTracker series of receivers except that all floating point values are now represented as fixed point integer numbers with explicit or implied scale factors Abbreviation Words Note 1 Each binary message consists of a header portion and a data port
121. n 1970 Republic of Maldives Geodetic Datum 1949 New Zealand Graciosa Base SW 1948 Azores Faial Graciosa Pico Sao Jorge Terceira Guam 1963 Guam Gunung Segara Indonesia Kalimantan GUX 1 Astro Guadalcanal Island Herat North Afghanistan Hjorsey 1955 Iceland Hong Kong 1963 Hong Kong Hu Tzu Shan Taiwan MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 84 Indian Bangladesh Indian India Nepal Indian 1954 Thailand Vietnam Indian 1975 Thailand Ireland 1965 Ireland ISTS 061 Astro 1968 South Georgia Islands ISTS 073 Astro 1969 Diego Garcia Johnston Island 1961 Johnston Island Kandawala Sri Lanka Kerguelen Island 1949 Kerguelen Island Kertau 1948 West Malaysia amp Singapore Kusaie Astro 1951 Caroline Islands L C 5 Astro 1961 Cayman Brac Island Leigon Ghana Liberia 1964 Liberia Luzon Philippines Excluding Mindanao Luzon Philippines Mindanao Mahe 1971 Mahe Island Massawa Ethiopia Eritrea Merchich Morocco Midway Astro 1961 Midway Islands Minna Cameroon Minna Nigeria Montserrat Island Astro 1958 Montserrat Leeward Islands Nahrwan Oman Masirah Island Nahrwan Saudi Arabia Nahrwan United Arab Emirates
122. n link Bit 1 true 5 Bit 15 to e E ee Standard Bit degrees 1 true Geh deviation Note 12 UI 0 to 300 14 GPS week number UI weeks 0 to 32767 15 16 GPS seconds from epoch UDI S 0 to 604799 17 18 GPS nanoseconds from epoch UDI ns 0 to 999999999 19 UTC day UI day 1 to 31 20 UTC month UI month 1 to 12 21 UTC year UI year 1980 to 2079 22 UTC hours UI h 0 to 23 23 UTC minutes UI min 0 to 59 24 UTC seconds UI S 0 to 59 25 26 UTC nanoseconds from epoch UDI ns 0 to 999 999999 27 28 Latitude DI rad 0 to r 2 10 29 30 Longitude DI rad X0 to rr 10 31 32 Height DI m 0 to 50000 10 33 Geoidal separation 1 m 0 to 200 10 34 35 Ground speed UDI m s 0 to 1000 10 36 True course UI rad 0 to 21 10 37 Magnetic variation 1 rad 0 to 11 4 10 38 Climb rate 1 m s 300 10 39 Map datum Note 13 UI 0 to 188 and 300 to 304 40 41 Expected horizontal position error Note 14 UDI m 0 to 320000000 10 42 43 Expected vertical position error Note 14 UDI m 0 to 250000 10 44 45 Expected time error Note 14 UDI m 0 to 300000000 10 46 Expected horizontal velocity error Note 14 UI m s O to 10000 10 47 48 Clock bias Note 14 DI m 0 to 9000000 10 49 50 Clock bias standard deviation Note 14 DI m 0 to 9000000 10 51 52 Clock drift Note 14 DI m s 0 to 1000 10 53 54 Clock drift standard deviation Note 14 DI m s 0 to 1000 10 55 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enable
123. navigation solution passes all validity criteria set using the binary solution validity criteria message a GGA message is generated automatically If any of the validity criteria are invalid for the solution a GGA message is not generated The contents of the GGA message are Sample message described in Table 3 47 PRWIERR 0 0 005BC9 0I 3 6 1 3 GPS fix data GGA This message contains time position and fix Sample message related data for the Jupiter receiver When a Message ID ERR GPGGA 222435 3339 7334 N 11751 7598 W 2 06 1 33 27 0 M 34 4 M 7 0000 41 Rate variable Fields 3 Field No Symbol Field description Field type Example Start of sentence and address field PRWIERR Class 0 user mode exception 1 executive mode exception 2 trap 3 executive error 4 ESR error 5 user error X X 0 Exception trap or error number X X 0 Word address of condition hhhhhh 005BC9 CKSUM Checksum hh 01 lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Table 3 46 ERR message Navman proprietary error status Message ID GGA while receiver is in navigation mode see Note 1 Rate variable defaults to 1 Hz Fields 14 Field No Symbol Field description Field type Example GGA Start of sentence and address field GPGGA POS UTC UTC of position hours minutes seconds
124. nd 4 7 for more details Parameter Value Description datum WGS 84 mask angle 10 degrees cold start control enabled timeout 300 ns platform class automotive altitude measurement validity mark altitude solutions valid maximum EHPE 100 m maximum expected EVPE 150 m criterion for minimum number of satellites used for a solution zero DGPS validity not required for a valid solution held altitude enabled position pinning enabled enabled automatically disabled when DGPS corrections are available ground track smoothing enabled only when DGPS is not available DGPS disable false i e DGPS is active if corrections are available host port communication parameters Navman binary 9600 N 8 1 host port communication parameters NMEA 4800 N 8 1 host port communication parameters RTCM inout only 9600 N 8 1 solution validity criteria after a fully determined or successful transition to navigation Table 4 1 Default configuration data MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 59 4 3 4 Differential GPS DGPS control Jupiter GPS DGPS operation disable and correction timeout When DGPS disable is asserted the navigation solution is computed without the benefit of
125. nd a velocity has been established by the Kalman filter it will be used to propagate the state forward in the absence of further measurements for a limited time period until the estimated errors in the propagated velocity have reached certain limits Once these limits are reached Pedestrian low dynamics Automotive medium dynamics Aircraft high dynamics the velocity estimate is considered less reliable and is decayed exponentially with platform class dependent time constants 4 6 3 2 Measurement processing Once four satellites are available above the elevation mask angle with ephemeris data and sufficiently good geometry the Kalman filter begins to process the measurements The Kalman filter processes two measurements for each satellite the integrated carrier phase measurement also known as carrier smoothed pseudo range and the Doppler or range rate measurement 4 6 3 3 Altitude processing The receiver uses altitude aiding if a source is available and the Expected Vertical Position Error EVPE exceeds a threshold The sources available for aiding in the order of preference for use are 1 user entered altitude 2 held altitude ROM altitude acquisition only 3 ROM altitude acquisition only User entered altitude The user entered altitude input message binary Message 1219 is used to supply an altitude to the receiver The altitude can be specified as instantaneous valid until cleared from RAM or va
126. ng applications Navman customers using or selling Navman products for use in such applications do so at their own risk and agree to fully indemnify Navman for any damages resulting from such improper use or sale Product names or services listed in this publication are for identification purposes only and may be trademarks of third parties Third party brands and names are the property of their respective owners Additional information posted at www navman com is incorporated by reference Reader response Navman strives to produce quality documentation and welcomes your feedback Please send comments and suggestions to tech pubs navman com For technical questions contact your local Navman sales office or field applications engineer MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 90
127. non volatile storage This is why the format of output message 1117 is exactly the same In other words the output message is used to capture data while the input message is used to restore data Rate As required maximum rate 1 Hz Message Length 8 words Word No Name 1 4 Message header 5 Header checksum Sequence number Note 1 0 to 32767 0 off 1to4 on 6 7 Power management on duty cycle Note 2 8 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 2 In power management mode the RF power may be switched off to reduce power consumption The digital circuitry may be gated off and the processor idled when not needed This field gives the measurement engine permission to turn off the RF for the minimum off time in seconds Table 3 37 Message 1317 power management control MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 43 3 5 2 16 Message 1330 serial port communication two serial ports The contents of the serial parameters port communication parameters message are This message allows the user to set the described in Table 3 38 communication parameters for the receiver s Message ID 1330 Rate As required maximum rate 1 Hz Message
128. number Bit 0 minimises ROM usage bit 1 minimises RAM usage bits 2 15 are reserved Table 3 50 RID message Navman proprietary receiver ID MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 51 3 6 1 7 Recommended minimum specific GPS data RMC This message contains time date position course and speed data The fields in this message always contain data even when the receiver is not navigating This allows user initialised stored or default values to be displayed before a solution is Message ID RMC obtained The contents of the RMC message are described in Table 3 51 Sample message GPRMC 185203 A 3339 7332 N 11751 7598 W 0 000 121 7 160496 13 8 E 55 Rate variable defaults to 1 Hz Fields 11 Field No Symbol BMC Field description Start of sentence and address field Example GPRMC Field type POS_UTC seconds UTC of position hours minutes seconds decimal hhmmss ss 185203 PAS STAT Position status A Data valid V Data invalid Note 1 a A LAT Latitude 1111 11 3339 7332 LAT REF Latitude direction N 7 north S 7 south a N LON Longitude yyyyy yy 11751 7598 LON REF Longitude direction E east W west a W SPD Speed over ground knots X X 0 000 HDG Heading track made good degrees true X X
129. ny message containing data see Figure 3 2 When the word count field is zero the data checksum does not exist It is computed by summing modulo 216 all words in the data portion of the message and then complementing that sum The mathematical expression for the data checksum is 5 n SUM Mod2 62 word i If sum 32768 data checksum SUM else data checksum SUM where a Unary negation is computed as the two s complement of a 16 bit data word b Mod 216 indicates the least 16 bits of an arithmetic process That is carry bits from bit position 16 are ignored c The summation is the algebraic binary sum of the words indicated by the subscript i d The 32 768 sum value must be treated as a special case since it cannot be negated NOTE A CURRENT BUG CAUSES CHECKSUM ERRORS FOR A VALUE OF ZERO or 32 768 Data elements identified as reserved must be set to 5 N zero for input messages and are undefined for output messages All data storage that is not explicitly 1 6 defined should be handled as if marked reserved Unless otherwise stated the resolution of each numeric data item is one integer unit as specified by that item in the units field 3 4 NMEA messages format and sentence structure NMEA messages are output in response to standard Query Q or proprietary Log Control ILOG messages as described in Section 3 6 The timing of output messages is synchronised with the tim
130. omag html APPENDIX C NAVSTAR GPS operation NAVSTAR GPS is a space based satellite radio navigation system developed by the U S Department of Defense DoD GPS receivers provide land marine and airborne users with continuous 3D position velocity and time data This information is available free of direct charge to an unlimited number of users The system operates under all weather conditions 24 hours a day anywhere on Earth There are three major segments space segment control segment user segment The space segment This segment consists of a nominal constellation of 24 operational satellites including 3 spares These satellites have been placed in 6 orbital planes see Figure C 1 about 20200 km 10900 miles above the Earth s surface The satellites are in circular orbits with a 12 hour orbital period and inclination angle of 55 degrees This orientation normally provides a GPS user with a Figure C 1 NAVSTAR GPS operational satellite constellation minimum of 5 satellites in view from any point on Earth at any time Each satellite continuously broadcasts an RF signal at a centre frequency of 1575 42 MHz LI band This signal is modulated by a 10 23 MHz clock rate precise ranging signal and by a 1 023 MHz clock rate coarse acquisition C A code ranging signal Each of these two binary signals has been formed by a precision code p code or a C A code which is modulo 2 added to 50 bps navigation d
131. on angles they are quite consistent and modellable Variations in the index of refraction can cause differences between reference station and user in signal delays from 1 to 3 m for low lying satellites Ephemeris error differences between the actual satellite location and the location predicted by the satellite orbital data Normally these are quite small less than 3 m but they could be more than 30 m under SA Satellite clock errors differences between the satellite clock time and that predicted by the satellite data The oscillator that times the satellite signal is free running the GPS ground control station monitors it and establishes corrections that are sent up to the satellite to set the data message The user reads the data and adjusts the signal timing accordingly Satellite clock errors are completely compensated by differential operation as long as both reference and user receivers are employing the same satellite data Ephemeris errors unless they are quite large 30 m or more are similarly compensated by differential operation SA errors that affect the timing of the signals are also compensated by differential operation except that the corrections lose their validity after a period of time For users near the reference station the respective signal paths to the satellites are sufficiently close that compensation is almost complete As the separation increases between user and reference station the diffe
132. ote 1 Note 1 n must be less than or equal to 39 No more than 32 receiver 16 bit words of RTCM data should be delivered to the receiver with anyone message Word description number of words header 4 header checksum 1 reserved sequence number 1 RTCM data 32 data checksum 1 max number of words 39 Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 3 Raw demodulated data must conform to the 6 of 8 format described in the RTCM SC 1 04 standard The data must also be packed into one or more 16 bit words and should be ordered chronologically from earliest to latest Specifically Word 7 should represent the earliest data and Word n 1 should represent the latest Within each word the most significant bit bit 15 should represent the latest received bit and the least significant bit bit 0 should represent the earliest received bit Note that according to RTCM 6 of 8 format bits 6 and 14 should be set marking 1 and bits 7 and 15 should be set spacing 0 for each word The intent of this bit ordering is to allow the user to pass on the raw RTCM data without modification Table 3 41 Message 1351 raw DGPS RTCM SC 104 data MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 46 3 5 2 20 Message 1360 frequency st
133. out notice 44 3 5 2 17 Message 1331 message protocol control This message allows the user to set the message format protocol which will be used to communicate information to and from the receiver through the host serial I O port Currently the available protocols are binary with fixed point numbers and NMEA 0183 Storage for the protocol type parameter requires EEPROM The contents of the Message ID 1331 message protocol control message are described in Table 3 39 3 5 2 18 Message 1350 factory calibration input This message is used to inform the system about the quality of the frequency standard being used The contents of the factory calibration input message are described in Table 3 40 Rate As required maximum rate 1 Hz Message Length 9 words Word No Name Type Units Range 1 4 Message header 5 Header checksum 6 Sequence number Note 1 l 0 to 32767 7 Reserved must be zeroed out l 0 binary 8 Protocol type Note 2 l 1 NMEA 2 RTCM SC 104 9 Data checksum updated or changed since the last message input Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been Note 2 RTCM SC 104 is not a valid protocol for the host data stream Table 3 39 Message 1331 message protocol control Message ID 1350 Rate As required maximum rate 1 Hz Message Length 10 Word No Name Re
134. pecified in latitude and longitude and by the altitude above the WGS 84 spheroid Earth surface model 7 What are the addresses for U S FM DGPS service providers ACCQPOINT Communications Corp 2737 Campus Drive Irvine CA 92715 800 995 3477 Differential Corrections Inc DCI 10121 Miller Avenue Cupertino CA 95014 408 446 8350 8 Does the Jupiter receiver provide an over determined solution Jupiter receivers provide all in view parallel tracking of all visible satellites In SPS mode all valid measurements are used to produce an over determined navigation solution to minimise position excursions arising from SA and loss of signals In DGPS all valid measurements with valid DGPS corrections are used in an over determined solution For example if 8 satellites are in track all producing valid measurements and DGPS corrections are available for 7 of the 8 then 7 DGPS corrected measurements will be used in the over determined DGPS solution 9 How is heading data at low speeds derived Shouldn t the heading be derived from Doppler data rather than position differences Navman receivers compute velocity from the carrier loop Doppler information Heading angle is then computed from east and north velocity as the arc tangent Ve Vn When on SA induces an error on the GPS clock and thus the carrier Doppler information and pseudo range is corrupted but the carrier data is a better source of velocity information
135. pproved NMEA sentences A proprietary sentence contains the following elements in the order shown start of the sentence 24 2 P proprietary sentence ID 50 4 aaa OEMs mnemonic code lt valid characters OEMs data gt checksum field gt optional checksum field lt CR gt lt LF gt end of sentence delimiter OD OA 3 4 7 Checksum The checksum is the 8 bit exclusive OR no start or stop bits of all characters in the sentence including delimiters except for the and the optional delimiters The hexadecimal value of the most significant and least significant four bits of the result are converted to two ASCII characters 0 to 9 A to F for transmission The most significant character is transmitted first Description Carriage return end of sentence delimiter Line feed end of sentence delimiter Start of sentence delimiter Checksum field delimiter Field delimiter Reserved Reserved Reserved Reserved Table 3 2 NMEA reserved characters MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 11 Field Type Symbol Definition Special format fields Status Single character field A yes data valid warning flag clear V no data invalid warning flag set Latitude 1111 11 Fixed variable length field degrees minutes decimal two fixe
136. pproximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 The options list is a bit encoded configuration word represented as an ASCII four digit hexadecimal number bit 0 minimises ROM usage bit 1 minimises RAM usage bits 2 15 reserved Table 3 11 Message 1011 receiver ID MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 21 3 5 1 8 Message 1012 user settings output This message provides a summary of the settings for many of the user definable parameters Message ID 1012 The contents of the user settings output message are described in Table 3 12 Rate variable Message length 22 words Word No Resolution Message header Header checksum Set time Note 1 10 ms ticks 0 to 2147 483647 Sequence number Note 2 Operationa status 9 0 9 15 0 to 32767 Power management enabled Bit 1 enabled 9 1 Cold start disabled Bit 1 7 disabled 9 2 DGPS disabled Bit 1 disabled 9 3 Held altitude disabled Bit 1 disabled 9 4 Ground track smoothing disabled Bit 1 disabled 9 5 Position pinning disabled Bit 1 disabled 9 6 Quality measurement disabled Note
137. ration when less than four satellites are available or when required by operating conditions Altitude information required for 2D operation is determined by the receiver or may be provided by the OEM The Jupiter receivers contain two independent serial ports one of which is configured for primary input and output data flow using the National Marine Electronics Association NMEA 0183 format or Navman binary message format The second port is used to receive Differential GPS DGPS corrections in the Radio Technical Commission For Maritime Services RTCM SC 104 format The receivers support DGPS operations for improved accuracies over standard GPS A complete description of the serial data interface for the entire Jupiter series of GPS receivers is contained in this document For applications that require timing synchronisation to GPS accuracies the Jupiter receivers provide an output timing pulse that is synchronised to one second Universal Time Coordinated UTC boundaries 1 1 2 Receiver architecture Figure 1 2 illustrates the internal architecture of the Jupiter receivers Each receiver is designed around two custom SiRF devices that contain most of the required GPS functionality 1 The RF1A which contains all the RF down conversion and amplification circuitry and which presents sampled data to the Scorpio device MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subj
138. red from highest to lowest elevation which for sequential acquisition also dictates the order in which acquisition attempts are made Receiver position and current time are required to compute satellite positions from orbital data If position and or time is not considered to be well known i e their expected errors are large then the list is extended below the horizon and is filled to the maximum of 12 satellites If DGPS corrections are available the satellites represented in the corrections are used to set the list membership instead since they also represent satellites visible to a nearby transmitting DGPS base station New visible satellite lists are generated by events that could cause a change in satellite list membership or could indicate a significant change in a satellite position relative to the antenna These events include receipt of an elevation mask angle or candidate satellite specification command downloading of a new satellite almanac and changes in satellite health status reflected in new almanac or ephemeris data In the case where DGPS corrections are used to establish list membership a change in the set of satellites reflected in the corrections also causes a new list to be generated During initial acquisition a new list is generated when the receiver makes step adjustments to position and time In the absence of these events the visible satellite list is updated every 30 seconds The visible satell
139. rent ionospheric and tropospheric paths to the satellites may be sufficiently far apart that the atmospheric heterogeneities cause the delays to vary The extent of the difference constitutes an error in the DGPS measurement called spatial decorrelation This type of error will be greater at larger user to reference station separations Required DGPS Equipment The equipment consists of a GPS receiver with antenna a data processor a data link receiver with antenna and interfacing equipment as illustrated in Figure C 5 The data processor applies the corrections received from the reference station to the pseudoranges measured by the sensor Application of DGPS Corrections For each satellite employed by the user s receiver the correction obtained from the reference station message type 1 or 9 is added to the pseudorange measurement The correction itself is derived from the range and range rate adjusted to account for the time elapsed between the time of reception of the correction and the time of the user pseudo range measurement as follows PRC t PRC t RRC x t to where PRC t is the correction to be applied PRC to is the range correction from the message RRC is the range rate correction from the message to is the time reference of the correction t is the time associated with the pseudo range measurement MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and spec
140. rietary information and specifications subject to change without notice 16 3 5 1 3 Message 1003 visible satellites from this visible list are also provided The This message outputs the list of satellites visible contents of the visible satellites message are to the receiver and their corresponding elevations described in Table 3 7 and azimuths The best possible DOPs calculated Message ID 1003 Rate Variable default on update Message Length 51 words Word No Name Resolution Message header Header checksum 0 to 4294 967 295 0 to 32767 0 to 99 0 to 99 0 to 99 Set time Note 1 10 ms ticks Sequence number Note 2 Best possible GDOP Best possible PDOP Best possible HDOP Best possible VDOP 0 to 99 Best possible TDOP 0 to 99 Number of visible satellites UI 1 to 12 Visible satellite set Note 3 15 3 j Satellite PRN Note 4 0 to 32 16 3 j Satellite azimuth rad tm 10 17 3 j Satellite elevation rad tn 2 10 51 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binar
141. rs The contents of the INIT message Message ID INIT Rate as required Fields 14 0 0 M 0 0 T 162338 190594 Field No Symbol PRWIINIT Field description Start of sentence and address field Note 1 Field type Example PRWIINIT RESET Software reset flag A reset V don t reset Note 2 V RES 1 Reserved RES 2 Reserved LAT Latitude Note 2 3339 650 LAT REF Latitude direction N 7 north S 7 south Note 2 a N LON Longitude Note 2 yyyyy yy 11751 680 LON REF Longitude direction E east W west Note 2 a Ww ALT Altitude m Note 2 X X 64 131 oo jolo inr jolgv 2A SPD Ground speed Note 2 X X 0 0 CH SPD_TYP Ground speed units M m sec N knots K km hr Note 2 a M x HDG Heading 0 0 to 360 0 degrees north Note 2 X X 0 0 mi N HDG_TYP Heading type T true M magnetic Note 2 a T Co TIME UTC time h min s Note 2 162338 A DATE UTC date Note 2 190594 CKSUM Checksum optional lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Note 1 NMEA message prefix P Proprietary message indicator RWI Navman Systems Inc mnemonic INIT Initialisation message ID Note 2 this function is enabled by default Each of the fields 1 through 14
142. rs requires EEPROM The contents of the user defined datum message are described in Table 3 24 Note that datum definition does not imply datum use Message 1211 is used to specify the datum in Message ID 1210 use for the navigation function Also any message 1210 that contains an undefined datum code is ignored 3 5 2 3 Message 1211 map datum select This message allows the user to select a datum to be used by the receiver to transform its position solution The contents of the map datum select message are described in Table 3 25 Rate as required maximum rate is 1 Hz Message length 20 words Word No Name Resolution Message header Header checksum Sequence number Note 1 0 to 32767 User datum ID 300 304 Semi major axis integer part 6300000 to 6400000 Semi major axis fractional part 11 Inverse flattening integer part UI 0 to 9999 280 to 320 12 13 Inverse flattening fractional Part 0 to 999 999999 10 14 15 WGS 84 datum offset dX DI 0 to 9000000 10 16 17 WGS 84 datum offset dY DI 0 to 9000000 10 18 19 WGS 84 datum offset dZ DI 0 to 9000000 10 20 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Table 3 24 Message 1210 user defined datum
143. rt protocol selection 5 auxiliary port communication configuration 19 host port enable messages 6 memory options 20 reserved auxiliary port enabled messages 7 solution validity criteria 21 user datums 8 power management selections 22 frequency temperature table 9 selected datum 23 almanac 10 platform class 24 frequency standard calibration data 11 cold start control 25 nav configuration data 12 elevation mask angle 26 DR navigation parameters 13 satellite candidate list 27 gyro temperature table Note 4 This field is only valid when the data ID 23 Almanac Table 3 18 Message 1135 EEPROM update MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 29 3 5 1 15 Message 1136 EEPROM status in the status words indicate that those data blocks This message provides failure and storage status have been updated at least once in the EEPROM information for the EEPROM Bits set in the failure The contents of the EEPROM status message are words represent write failures during attempts to described in Table 3 19 update the corresponding blocks of data Bits set Message ID 1136 Rate variable Message length 18 words Word No Message header Header checksum Set time Note 1 10 ms ticks 0 to 4294 967 295 Sequence number Note 2 l 0 to 32767 9 0 Device not present Bit 1 not present 9
144. ry message header eeeeeeeeeeeeeeeee nennen nennen nent nin innen nnn nnne nnn nnns 9 3 2 1 Message header WOO EE 9 3 2 2 Message header Word ET 9 3 2 3 Message header e e E EE 9 3 2 4 Message header Word Aer oiie neern aa id denen ania neared 9 3 2 5 Message header WOId 5 rti tre fae geed ges agua viene Fiere EE eege 10 3 2 6 Log Me E ME 10 3 3 Binary message data et ESEEEEESEEEREEEEESEEEREEEESEREEEEEEEEEEEREEEESEEEEREEEEEEEEKEEEEEEEEEEEEEEEEKEEEEEEEE Sch 10 3 4 NMEA messages format and sentence structure NEEN 10 3 4 1 NMEA o tp t messages erret tente tenente Rein eae Ree E e Re EUA EEEE Eai 10 3 4 2 NMEAinp utmessage EE 11 3 4 3 NMEA message format Xros rine e SEENEN Ee BER P equ Rue EUH a RR cH t kao ERR aai aaa 11 3 4 5 NMEA 0183 approved Sentences eee nenne enne ennemis 11 3 4 6 Proprietary sentences oii teretes e Uns decd eee dote ehe eher ea goes eeu deb queE Dena 11 34 T CHECKSUM EM ME 11 3 5 Jupiter binary data messages eeeeseseeeeneeneneeeenen nnne nnne nnne nnn nennen 14 3 5 1 Binary output message descriptions sse em nennen 14 3 5 1 1 Message 1000 geodetic position status output seeneenn 14 3 5 1 2 Message 1002 channel Stan es eui eet do ai d von deeg 16 3 5 1 3 Message 1003 visible Satellites eene nnne 17 3 5 1 4 Message 1005 DGPS Sfat s ori teatri teta trot esee E
145. s intended as a component for an Original Equipment Manufacturer OEM product GPS satellites in various orbits around the Earth broadcast Radio Frequency RF ranging codes and navigational data messages The Navman Jupiter series GPS receivers continuously track all visible satellites and decode all available signals from them producing a highly accurate and robust navigation solution The Jupiter series receivers are designed for high performance and maximum flexibility in a wide range of OEM applications including handhelds panel mounts sensors and in vehicle automotive products These highly integrated digital receivers incorporate two custom SiRF devices that have the SiRF Jupiter chip set the RF1A and the Scorpio Digital Signal Processor DSP The combination of custom devices minimises the receivers size and satisfies harsh industrial requirements 1 1 Product overview 1 1 1 Description The receivers require DC power and a GPS signal from a passive or active antenna To provide the lowest total system cost with minimal power consumption each of the receivers provides only those components that are required for the majority of applications e g if a passive antenna can be used with a short cable no pre amplifier is required The all in view tracking of Jupiter series receivers provides robust performance in applications that require high vehicle dynamics or that operate in areas of high signal blockage suc
146. s of the channel status output measurement message are described in This message provides measurement and Table 3 10 associated data for each of the receiver s Message ID 1009 Rate variable Message length 22 words Word No Name Type Units Range Resolution 1 4 Message header 5 Header checksum 6 7 Set time Note 1 UDI 10 ms ticks 0to4294967295 8 Sequence number Note 2 l 0 to 32767 Satellite measurement sequence number Note 3 l 0 to 32767 ECEF navigation solution ECEF Position X Note 4 DI 0 to 9000000 12 13 ECEF Position Y Note 4 DI 0 to 9000000 10 14 15 ECEF Position Z Note 4 DI 0 to 9000000 10 16 17 ECEF Velocity X Note 4 DI 0 to 1000 10 18 19 ECEF Velocity Y Note 4 DI 0 to 1000 10 20 21 ECEF Velocity Z Note 4 DI 0 to 1000 10 22 Data checksum UI Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts The set time indicated is at the time the message is submitted to the output queue Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 The satellite measurement sequence number relates the position solution data to a particular set of satellite measurements found in binary Messages 1002 and 1007 channel summary message and channel measurement message respectively
147. s referred to as a pseudorange Changes in each of these pseudo ranges over a short period of time are also measured and processed by the receiver These measurements referred to as delta pseudoranges are used to compute velocity A minimum of four pseudo range measurements are required by the receiver to mathematically determine time and the three components of position latitude longitude and altitude The equations used for these calculations are shown in Figure C 2 The solution of these equations may be visualised as the geometric intersection of four ranges from four known satellite locations Figure C 3 illustrates triangulation one way to envision the navigation process For ease of understanding it is assumed that the user clock is synchronous After the four range equations are solved the receiver has estimates of its position and time R C x DT R Cx DT R C x DT Position equations X U A EUERE 06 Urru URE KUYA Z eem 6 X U a De 0 6 Pseudo range includes actual distance between satellite and user plus satellite clock bias user clock bias atmospheric delays and receiver noise Satellite clock bias and atmospheric delays are compensated for by incorporation of deterministic corrections prior to inclusion in nav solution X Y4 Z satellite position i 1 2 3 4 Satellite position broadcast in navigation 50 Hz message Receiver solves for
148. sensor reading at TREF Note 6 counts 0 to 65535 SO temperature sensor scale factor Note 6 C count 0 to 2 Uncertainty coefficients UO Note 7 0 to 274 29 U1 Note 7 s s C 0 to t2 2 255 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 Unique identification of each update This allows a different set of data to be in use while newer data are only stored to EEPROM The issue number is preserved from run to run if non volatile storage is available Note 4 Defines a cubic in T TINF Over a range of TINF 65 degrees C each term can produce from 0 002 to 60 ppm approximately Note 5 Unused Note 6 These parameters define the temperature sensor scaling according to the equation T TREF TFILT TO SO Note 7 Defines a linear equation in T TINF Over a range of TINF 65 C each term can produce from 0 002 to 60 ppm approximately Table 3 15 Message 1110 frequency standard parameters in use M
149. sfied MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 69 Ephemeris data has been collected by the receiver for at least four satellites DGPS corrections have been received for at least the same four satellites and these corrections are not older than the time limit specified in the Differential GPS Control message binary Message 1214 The Issue Of Data Ephemeris IODE is the same for both the receiver collected ephemeris and the RTCM SC 104 corrections All of the applicable satellites have good health or have been declared healthy for DGPS purposes by the RTCM SC 104 source The User Differential Range Error UDRE reported by the RTCM SC 104 source is equal to or less than 8 m for all four satellites The RTCM SC 104 source declares itself to be in good health The user has not turned DGPS operation off 4 7 4 5 Disabling DGPS operation The user may disable DGPS operation through the Differential GPS Control message binary Message 1214 When disabled the receiver will not use DGPS information to compute a position solution nor will the information be erased During the time that DGPS operation is disabled and DGPS solutions are not being computed RTCM processing continues as long as RTCM messages are being sent to the receiver The data contained within these messages will be used to update the receiver s internal DGPS database
150. sk angle satellites whose measurements may be used At least four satellites are required to estimate position and time and therefore to compute a MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 61 GDOP The DOP fields in message 1003 are set to maximum values when GDOP cannot be computed 4 5 2 Acquisition modes Two methods of satellite acquisition are used by the Jupiter GPS receiver sequential acquisition and parallel acquisition 4 5 2 1 Sequential acquisition Sequential acquisition describes the acquisition of a satellite with all non tracking channels An example of this acquisition mode is Cold Start in which individual satellite acquisitions are attempted one at a time using all available channels to cover the wide Doppler uncertainty As satellites are acquired they stay in track on one channel with the remaining channels available for the next acquisition Sequential acquisition is always used to acquire the first satellite The receiver will automatically transition to parallel acquisition after the first satellite is acquired during a Warm Start or an Initialised Start 4 5 2 2 Parallel acquisition Parallel acquisition describes the acquisition of a satellite with a single non tracking channel An example of this acquisition mode occurs after the first satellite is acquired in Warm Start in which all of the visible satelli
151. solution Message header Header checksum Sequence number Note 1 0 to 32767 Oscillator temperature Note 2 C 40 to 85 0 01 8 9 Oscillator frequency error ppm 0 to 51 0 01 10 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 2 Externally supplied temperature measurement An external temperature input causes the internal temperature sensor to be ignored as a source of temperature data Table 3 40 Message 1350 factory calibration input MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 45 3 5 2 19 Message 1351 raw DGPS RTCM SC 104 compatibility with the earlier MicroTracker GPS data receiver and may be used in lieu of the auxiliary This input message contains DGPS RTCM SC 104 port data The contents of the raw DGPS RTCM data The message is provided for backwards SC 104 data message are described in Table 3 41 Message ID 1351 Rate As required The maximum allowable rate is once every 100 ms Note 1 Message Length Varies with message Word No Name Type Message header Header checksum Sequence number Note 2 l 0 to 32767 Any valid RTCM 104 raw data in multiples of 16 bits not to exceed 32 16 bit words Note 3 Data checksum N
152. solution P Code Precision Code a spread spectrum direct sequence code that is used primarily by military GPS receivers to determine the range to the transmitting GPS satellite Parallel receiver a receiver that monitors four or more satellites simultaneously PC Personal Computer PCMCIA Personal Computer Memory Card International Association PDOP Position Dilution of Precision A measure of how much the error in the position estimate produced from satellite range measurements is amplified by a poor arrangement of the satellites with respect to the receiver antenna Pi or m the mathematical constant having a value of approximately 3 14159 P P Peak to Peak PPS Pulse Per Second Note PPS can also stand for Precise Positioning Service The GPS positioning velocity and time service which will be available on a continuous worldwide basis to users authorised by the DoD PRN Pseudo random Noise Number The identity of the GPS satellites as determined by a GPS receiver Since all GPS satellites must transmit on the same frequency they are distinguished by their pseudo random noise codes PRR Pseudo Range Rate Pseudo range the calculated range from the GPS receiver to the satellite determined by measuring the phase shift of the PRN code received from the satellite with the internally generated PRN code from the receiver Because of atmospheric and timing effects this time is not exact Therefore it is
153. ssage 1216 cold start control This message allows the user to disable the cold start acquisition mode of the receiver When cold start is enabled at power on the cold start timer is set to O If a satellite is not acquired before the cold start time out is exceeded the cold start acquisition mode starts If a satellite is acquired the cold start timer is reset to O the receiver is re positioned under the satellite and the search Message ID 1214 continues until either the receiver navigates or the timer is exceeded Cold start acquisition mode does not use the initial conditions of position time and almanac This causes the receiver to look at a wider range of frequencies and satellites The default cold start timer is 5 minutes Normal operation is to leave cold start enabled However in certain enclosed situations e g garages houses office buildings etc faster acquisitions may be achieved with cold start disabled storage of the cold start disable parameter requires EEPROM The contents of the cold start control message are described in Table 3 29 Rate as required maximum rate 1 Hz Message length 9 words Word No Name Message header Header checksum Sequence number Note 1 DGPS disable Correction data base reset 0 to 32767 1 disable 1 reset Reserved Correction timeout UI 0 to 32767 Data checksum Note 1 The sequence number is a count t
154. stored continuously in memory RAM or EEPROM Table 3 31 Message 1219 user entered altitude input MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 38 3 5 2 10 Message 1220 application platform application in which the receiver is being used control Storage for the Platform parameter requires This message allows the user to adjust the EEPROM The contents of the application platform receiver s dynamics based on the type of control message are described in Table 3 32 Message ID 1220 Rate as required maximum rate is 1 Hz Message length 8 words Word No Name Type Units Range Resolution Message header Header checksum Sequence number Note 1 0 to 32767 0 default 1 7 static 2 pedestrian Platform 3 marine lakes 4 marine sea level 5 land auto 6 air 8 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Table 3 32 Message 1220 application platform control MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 39 3 5 2 11 Message 1221 nav configuration This message allows the user to control various features in the
155. sults of the flash ROM checksum validation test The contents of the flash boot status message are described in Table 3 21 Message ID 1180 3 5 1 18 Message 1190 error status This message provides diagnostic information if the receiver encounters an error during execution of its firmware The contents of the error status message are described in Table 3 22 Rate as required Message length 7 words 0 checksum pass 1 checksum fail 2 copying header 3 waiting for a command Word No Name Type Units Range 1 4 Message header 5 Header checksum 6 Boot status Note 1 IU short 7 Data checksum Note 1 Table 3 21 Message 1180 flash boot status Message ID 1190 Rate variable Message length 13 words Word No Name Type Units Range 1 4 Message header 5 Header checksum 6 7 Set time Note 1 UDI 10 ms ticks 0 to 4294967 295 8 Sequence number Note 2 l 0 to 32767 9 Class Note 3 UI 0 to 5 10 Number l 11 Code environment CENV UI 12 Program counter PC UI 13 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 rang
156. t consists of all printable ASCII characters 204 x to 7Eyex except for the reserved characters listed in Table 3 2 Each NMEA message or sentence consists of a set of fields separated by a comma delimiter character Each field can contain either a string of valid characters or no characters null field Valid characters must conform with the formats described in Table 3 3 Character Hex value Decimal value The maximum number of characters in a sentence is 82 consisting of a maximum of 79 characters between the starting delimiter and the terminating lt CR gt and lt LF gt Since the number of data fields can vary from sentence to sentence it is important that the listener or application software locate fields by counting delimiters rather than counting the total number of characters received from the start of the sentence 3 4 5 NMEA 0183 approved sentences An approved NMEA 0183 sentence contains the following elements in the order shown Start of the sentence 24 2 address field Talker identifier and sentence formatter data field gt Zero or more data fields checksum field gt Optional checksum field lt CR gt lt LF gt End of sentence delimiter OD 0A Note Since the Jupiter receiver is a GPS device the talker identifier is always GP 3 4 6 Proprietary sentences Proprietary sentences allow OEMs to transfer data that does not fall within the scope of a
157. t indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 If this bit is set the receiver only uses perfect measurements i e without errors in tracking status or data If the bit is not set measurements that are not perfect but still good enough to use under SPS conditions are used Note 4 The selected candidate list is a 32 bit flag each bit representing candidate selection status for one satellite ie bit 0 SV1 status bit 1 SV2 status bit 31 SV32 status Table 3 12 Message 1012 user settings output MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 22 3 5 1 9 Message 1100 built in test results BIT but may also be queried manually as needed This message provides detailed test results of the Non zero device failure status indicates failure last BIT commanded since power up It is output The contents of the BIT results message are automatically after the completion of a commanded described in Table 3 13 Message ID 1100 Rate Variable Message Length 20 words Word No Resolution Message header Header checksum 0 to Set time Note 1 10 ms ticks 4294967295 Sequence number Note 2 l 0 to 32767 ROM failure Note 3 UI RAM failure Note 3 UI EEPROM failure Note 3 UI Dual port RAM failure Note 3 UI
158. temperature polynomial coefficients and scale factors used by the receiver s frequency standard compensation model The contents of the frequency standard Note Message 1310 is primarily used to input key parameters from GPS systems without non volatile storage This is why the format of output Message 1110 is exactly the same In other words the output message is used to capture data while the input message is used to restore data input parameters message are described in Table 3 36 Message ID 1310 Rate as required maximum rate 1 Hz Message length 20 words Word No Name 1 4 Message header Sequence number Note 1 l 0 to 32767 0 to 65535 Resolution Frequency standard issue number Note 2 Ul Temperature characteristi s s 0 to 2 s s C 0 to x2 s s C 0 to 275 s sl C 0 to 2 C 0 to 100 CO ageing and calibration offset Note 3 l C1 linear term Note 3 l C2 second order term Note 3 l l l C3 third order term Note 3 TINF inflection point Note 3 Temperature dynamics DO Note 4 l D1 Note 4 l Temperature sensor calibration TREF calibration reference temperature Note 5 TO temperature sensor reading at TREF Note 5 17 SO temperature sensor scale factor Note 5 l l C 0 to 100 16 Ul counts 0 to 65535 C count 0 to 23 Uncertainty coefficients 18 UO Note 6 l s s 19 U1 Note 6 l s
159. ters 12 0 14 0 7 bits Port 2 character width Bit 1 8 bits Port 2 stop bits Bit i S h 0 7 no parity Port 2 parity i 1 odd parity 2 7 even parity 0 custom 1 300 2 600 3 1200 4 2400 5 4800 Port 2 bps rate Note 3 6 9600 7 19200 8 38400 9 57600 10 76800 11 115200 19 Port 2 pre scale Note 3 UI 0 to 255 20 Port 2 post scale Note 3 UI 0 to 7 21 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 When a custom bits per second bps rate is selected the bps rate is equal to CPU clock 16 x pre scale x 2post scale Table 3 17 2 of 2 Message 1130 serial port communication parameters in use message MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 28 3 5 1 14 Message 1135 EEPROM Update configured for output on update the default as it This message provides dynamic sta
160. tes are assigned a channel and acquisitions are attempted simultaneously Note that even though a single channel is being used a large Doppler uncertainty can still be covered with extended search time 4 5 2 3 Adaptive threshold based signal detection To extend the weak signal reception capability of the receiver an adaptive noise threshold based detection scheme has been implemented in the receiver software With this approach a variable detection threshold is computed from the average cross correlation value of the received signal with a Pseudo Random Noise PRN code This PRN code is similar in structure to the GPS satellite PRN codes but uses a PRN ID that is not assigned to any of the GPS satellites The computation of the received C No power is also based on the cross correlation value as determined above This scheme lowers the average detection threshold for weak signals thus improving the receiver s ability to acquire and track satellites under these conditions Conversely this scheme sets a higher threshold when strong signals are received This method results in more reliable acquisition of satellites and a corresponding reduction in TTFF over a wider variation of GPS signal strength conditions 4 5 2 4 Overall search process Figure 4 1 depicts the overall search process as it interacts with the visible satellite list generation described in section 4 5 1 Sequential or parallel acquisition is selected based on channel
161. the OEM to specify if solutions that make use of an altitude measurement should be marked valid Altitude is not used in the solution unless it is necessary because of deteriorating EVPE or untracked satellites When it is required the OEM may wish this to be an indication that the solution is invalid for purposes of the specific application The default is that solutions using altitude measurements may be marked valid 4 6 4 2 DGPS used validity criterion The DGPS used validity criterion indicates an invalid navigation solution if DGPS is unavailable after it has been required The system default is that DGPS is not required for a valid solution 4 6 4 3 Number of satellites used validity criterion The number of satellites used validity criterion indicates an invalid navigation solution if the minimum number of satellites required to be in the solution is not met The default for this test is zero A solution may be reported as valid with no measurements used so long as the EHPE and EVPE criteria pass and a Kalman filter solution has been previously computed The reason the default is set to zero is to allow the receiver to coast through brief outages without declaring the solution invalid e g for example under a freeway overpass MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 66 If the measurements are lost for a long time the EHPE and EVPE wi
162. the user direction VSWR Voltage Standing Wave Ratio WGS 84 World Geodetic System 1984 a mathematical ellipsoid designed to fit the shape of the entire Earth It is often used as a reference on a worldwide basis while other ellipsoids are used locally to provide a better fit to the Earth in a local region GPS uses the centre of the WGS 84 ellipsoid as the centre of the GPS ECEF reference frame MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 75 Appendix B References This appendix provides a list of documents that may help a user of Navman s GPS receivers to learn more about the way the GPS can be used Not all of these documents have been referred to in the text of this document 1 Global Position System Standard Positioning Service Signal Specification United States Department of Defense 2 Standard For Interfacing Marine Electronic Devices NMEA 0183 National Marine Electronics Association 3 RTCM Recommended Standards for Differential NAVSTAR GPS Service Radio Technical Commission for Maritime Services 4 Principle of Operation of NAVSTAR and System Characteristics Milliken and Zoller Global Positioning System Vol 1 1980 pp 3 14 5 Department of Defense World Geodetic System 1984 DMA TR 8350 2 6 Internet web site for the National Geophysical Data Centre NGDC http julius ngdc noaa gov seq potfld ge
163. together with their corresponding message IDs Power up default messages are also identified Binary messages are transmitted and received across the host port serial I O interface RS 232 default communication parameters are 9600 bps no parity 8 data bits 1 stop bit 3 5 1 Binary output message descriptions This section provides details for each of the output binary messages Message ID 1000 3 5 1 1 Message 1000 geodetic position status output This message outputs the receiver s estimate of position ground speed course over ground climb rate and map datum A solution status indicates if the solution is valid based on the solution validity criteria the type of solution and the number of measurements used to compute the solution The polar navigation flag is used to indicate that the solution estimate is too close to the North or South Pole to estimate longitude When this flag is true the longitude and true course outputs are invalid and are not updated Users operating near the poles should use the ECEF position status output message See Table 3 5 Rate variable defaults to 1 Hz Message length 55 words Word No Message header Header checksum Set time Note 1 10 ms ticks 0 to 4294967295 Sequence number Note 2 0 to 32767 Satellite measurement sequence number Note 3 0 to 32767 Navigation solution validity 10 0 10 15 10 0 Solution invalid altitude
164. tting Diode LPTS Low Power Time Source LSB Least Significant Bit m s metres per second units of velocity m s s metres per second per second units of acceleration m s s s metres per second per second per second units of impulse or jerk Mask angle The minimum GPS satellite elevation angle permitted by a particular GPS receiver design Measurement error variance The square of the standard deviation of a measurement quantity The standard deviation is representative of the error typically expected in a measured value of that quantity MFI Multi Function Interface MHz Megahertz MR Master Reset MSB Most Significant Bit MSL Mean Sea Level MTBF Mean Time Between Failure Multipath errors GPS positioning errors caused by the interaction of the GPS satellite signal and its reflections mV Milli Volt mW Milli Watt NF Noise Factor or Noise Figure NMEA National Marine Electronics Association Obscuration term used to describe periods of time when a GPS receiver s line of sight to GPS satellites is blocked by natural or man made objects OEM Original Equipment Manufacturer Over determined solution the solution of a system of equations containing more equations than unknowns The GPS receiver computes when possible an over determined solution using the measurements from all GPS satellites it can track instead of the four necessary for a three dimensional position
165. tus notification will provide a notification of all stored configuration for EEPROM writes It contains the data block changes as they occur The contents of the ID for the last set of data which was written to EEPROM update message are described in EEPROM This message is most useful when Table 3 18 Message ID 1135 Rate variable default on update Message length 10 words Word No Name Type Units Range 1 4 Message header 5 Header checksum 6 7 Set time Note 1 UDI 10 ms ticks 0 to 4294967 295 8 Sequence number Note 2 l 0 to 32767 9 0 9 7 Data ID Note 3 Bit 0 to 27 9 8 9 15 Satellite PRN Note 4 Bit 0 to 32 10 Data checksum Note 1 Set time is an internal 10 millisecond T10 count since power on initialisation enabled the processor interrupts It is not used to derive GPS time but only serves to provide a sequence of events knowledge The set time or T10 count references the receiver s internal time at which the message was created for output The T10 range is approximately 71 weeks Note 2 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message output Note 3 0 status 14 antenna selection 1 position 15 user entered altitude 2 UTC iono 16 DGPS control 3 frequency standard cubic parameters 17 host port protocol selection 4 host port communication configuration 18 auxiliary po
166. ty measurements Note 2 0 enabled 1 7 disabled 7 4 Enable jamming detect 0 enabled 1 disabled 7 5 7 15 Reserved must be zeroed out 0 8 14 Reserved must be zeroed out 15 Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Note 2 When this bit is set the receiver will only use perfect measurements ie measurements without any errors in tracking status or data If the bit is not set the system uses measurements that while not perfect are still good enough to use under SPS conditions Table 3 33 Message 1221 nav configuration Message ID 1300 Rate as required maximum rate approximately 0 1 Hz Message length 8 words Word No Name Message header Header checksum Sequence number Note 1 0 to 32767 Reserved Data checksum Note 1 The sequence number is a count that indicates whether the data in a particular binary message has been updated or changed since the last message input Table 3 34 Message 1300 perform built in test command MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 40 3 5 2 13 Message 1303 restart command The contents of the restart command message This message commands a full r
167. ual port RAM failure Note 2 0000 DSP FAIL Digital signal processor failure Note 2 0000 RTC FAIL Real time clock failure Note 2 0000 SP1 ERR Serial port 1 receive error count 0 SP2 ERR Serial port 2 receive error count 0 SP1_RCV Serial port 1 receive character count 15 SP2 ROV Serial port 2 receive character count SW VER Software version Checksum lt CR gt lt LF gt Sentence terminator lt CR gt lt LF gt Note 1 NMEA message prefix P proprietary message indicator RWI Navman Systems Inc mnemonic BIT BIT results message ID Note 2 A value of zero indicates a test has passed A non zero value indicates a device failure Missing devices are reported as failures Therefore the OEM s BIT pass fail should ignore words for components that are not in the system under test Note The dual port RAM failure test is currently not implemented so field 4 will report a value of zero O SOINID AR WO NM A me sch 1 EH Table 3 45 BIT message Navman proprietary built in test results MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 48 3 6 1 2 Navman proprietary error status ERR This message provides diagnostic information if the receiver encounters an error during execution of its firmware The contents of the ERR message are described in Table 3 46
168. used Note 4 i 1 true 10 1 Solution invalid no differential GPS Note 4 i 1 true 10 2 Solution invalid not enough satellites in track Note 4 i 1 true 10 3 Solution invalid exceeded max EHPE Note 4 i 1 true 10 4 Solution invalid exceeded max EVPE Note 4 i 1 true 10 5 Solution invalid no DR measurements Note 5 i 1 true 10 6 Solution invalid no DR calibration Note 6 i 1 true 10 7 Solution invalid no concurrent DR calibration by GPS Note 7 i 1 true 10 8 10 15 Reserved Navigation solution type 11 0 11 15 11 0 Solution type propagated solution Note 8 1 propagated 1 altitude used Wa Solution type altitude used 11 2 Solution type differential 1 differential 11 3 Solution type PM 1 RF off 11 4 Solution type GPS Note 9 i 1 true 11 5 Solution type concurrent GPS calibrated DR Note 10 i 1 true 11 6 Solution type stored calibration DR Note 11 i 1 true 11 7 11 15 12 Number of measurements used in solution 0 to 12 Reserved Table 3 5 1 of 2 Message 1000 geodetic position status output MNO02000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 14 Word No Name Type Units Range Resolution Non DR link polar navigation DR navigatio
169. y The various types of configuration data are briefly described in the following paragraphs 4 3 2 Geodetic datums Jupiter GPS receivers provide two configuration features related to datums datum selection and datum definition Datum selection controls the transformation used for all navigation outputs and inputs Over 180 pre defined datums are available for user configuration Datum definition allows the user to specify a custom datum that can be used in the same way as an element of the pre defined set A maximum of five user defined datums is supported Refer to section 4 6 Navigation for more details 4 3 3 Satellite selection Jupiter GPS receivers provide two configuration features related to satellite selection elevation mask angle and candidate satellite specification Satellite elevation mask angle defines the elevation angle that is used to screen satellites for inclusion in the navigation solution and Dilution of Precision DOP calculations Satellites that fall between the elevation mask angle and the horizon 0 degree mask are tracked when possible to gather their ephemeris data so they are ready to be used when they rise above the elevation mask Satellite candidate specification is used to explicitly control inclusion in the visible list satellites above horizon By default a satellite is a candidate until it is excluded at which point it must be re selected to be a candidate again See sections 4 6 a
170. y error in the table shares this common offset value Note 3 Flag to indicate that the offset has not been established Note 4 Filtered estimate of accumulated error in the table offset value Note 5 Filtered estimate of the current ageing rate Note 6 Whole week number of the last update of the ageing rate Note 7 LSB the approximate time of last table entry update MSB the frequency error at each table temperature less the table offset Table 3 42 Message 1360 frequency standard table input data Message ID 1380 Rate As required Message Length 7 words Word No Message header Header checksum Request flag 0 false Boolean nonzero true Data checksum Note This message does not provide the sequence number as word 6 Table 3 43 Message 1380 flash re program MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 47 3 6 Jupiter NMEA data messages Output message name Message ID Navman proprietary built in test results This section describes the NMEA data messages of the Jupiter GPS receiver All of the output and Navman proprietary error status input NMEA messages are listed in Table 3 44 GPS fix data together with their corresponding message IDs GPS DOP and active satellites Power up default messages are also identified GPS satellites in view
171. y message has been updated or changed since the last message output Note 3 Only the satellite sets for the number of satellites reported in word 14 of this message are valid Note 4 j the number of visible satellites minus one when the number of visible satellites is greater than zero Table 3 7 Message 1003 visible satellites MN002000A 2004 Navman NZ Ltd All rights reserved Proprietary information and specifications subject to change without notice 17 3 5 1 4 Message 1005 DGPS Status processed by the receiver The contents of the This message contains DGPS status information DGPS status message are described in Table derived from the last set of differential corrections 3 8 Message ID 1005 Rate Variable Message Length 25 words Word No Message header Header checksum Set time Note 1 UDI 10 ms ticks 0 to 4294967 295 Sequence number Note 2 l 0 to 32767 Status 9 0 9 15 Station health Bit 1 station bad User disabled Bit 1 user disabled Reserved Station ID UI 0 to 1023 Age of last correction UI 0 to 999 Number of available corrections UI 0 to 12 Correction status per satellite Note 3 Satellite PRN Note 4 UI 1 to 32 Local ephemeris Bit 1 ephemeris not available RTCM corrections Bit 1 corrections not available RTCM UDRE Bit 1 UDRE too high Satellite health 1 7 satellite data indicates bad hea

Navman 11 GPS Receiver User Manual

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