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1. Description Fix not available or invalid GPS SPS Mode fix valid Differential GPS SPS Mode fix valid w N GPS PPS Mode fix valid GLL Geographic Position Latitude Longitude Table B 4 contains the values for the following example GPGLL 3723 2475 N 12158 3416 W 161229 487 A 2C Table B 4 GLL Data Format Name Example Units Description Message ID GPGLL GLL protocol header Latitude 3723 2475 ddmm mmmm N S Indicator n N north or S south Longitude 12158 3416 dddmm mmmm E W Indicator W E east or W west UTC Position 161229 487 hhmmss sss Status A A data valid or V data not valid Checksum 2C lt CR gt lt LF gt End of message termination GSA GNSS DOP and Active Satellites Table B 5 contains the values for the following example GPGSA A 3 07 02 26 27 09 04 15 1 8 1 0 1 5 33 Table B 5 GSA Data Format Name Example Units Description Message ID GPGSA GSA protocol header Model A See Table B 6 Mode2 3 See Table B 7 Satellite Used 07 Sv on Channel 1 Satellite Used 02 Sv on Channel 2 Satellite Used Sv on Channel 12 PDOP 1 8 Position dilution of Precision HDOP 1 0 Horizontal dilution of Precision VDOP 1 5 Vertical dilution of Precision Checksum 33 lt CR gt lt LF gt End of message termination 1 Satellite used in solution Table B 6 Model Value Description M Manual forc2. CR gt lt LF gt lt msg gt 0 GGA 1 GLL 2 GSA 3 GSV 4 RMC 5 VTG lt mode gt 0 SetRate 1 Query lt rate gt Output every lt rate gt seconds off 0 max 255 lt cksumEnable gt O disable Checksum 1 Enable checksum for specified message Example 1 Query the GGA message with checksum enabled O PSRF103 00 01 00 01 25 Example 2 Enable VTG message for a 1Hz constant output with checksum enabled PSRF103 05 00 01 01 20 Example 3 Disable VTG message O PSRF103 05 00 00 01 21 E LLA Navigation Initialization ID 104 Parameters required to start using Lat Lon Alt This command is used to initialize the module for a warm start by providing current position in Latitude Longitude Altitude coordinates clock offset and time This enables the receiver to search for the correct satellite signals at the correct signal parameters Correct initialization parameters will enable the receiver to acquire signals more quickly and thus will produce a faster 15 navigational soution When a valid LLANavigationInitialization command is received the receiver will restart using the input parameters as a basis for satellite selection and acquisition Format PSRF104 lt Lat gt lt Lon gt lt Alt gt lt ClkOffset gt lt TimeOfWeek gt lt WeekNo gt lt ChannelCount gt lt ResetCfg gt CKSUM lt CR gt lt LF gt lt Lat gt Latitude position assumed positive north of equator and negative south of equator float possibly signed
3. available For example to change navigation parameters When a valid message is received the parameters will be stored in battery backed SRAM and then the receiver will restart using the saved parameters Format PSRF100 lt protocol gt lt baud gt lt DataBits gt lt StopBits gt lt Parity gt CKSUM lt CR gt lt LF gt lt protocol gt 0 SiRF Binary 1 NMEA 4 USERI lt baud gt 1200 2400 4800 9600 19200 38400 lt DataBits gt 8 7 Note that SiRF protocol is only valid f8 Data bits lt StopBits gt 0 1 lt Parity gt 0 None 1 Odd 2 Even Example 1 Switch to SiRF Binary protocol at 9600 8 N 1 PSRF100 0 9600 8 1 0 0C lt CR gt lt LF gt Example 2 Switch to User protocol at 38400 8 N 1 PSRF100 4 38400 8 1 0 38 lt CR gt lt LF gt Checksum Field The absolute value calculated by exclusive OR the 8 data bits of each character in the Sentence between but excluding and The hexadecimal value of the most significant and least significant 4 bits of the result are convertted to two ASCII characters 0 9 A F for transmission The most significant character is transmitted first lt CR gt lt LF gt Hex OD OA 12 B Navigation Initialization ID 101 Parameters required for start This command is used to initialize the module for a warm start by providing current position in X Y Z coordinates clock offset and time This enables the receiver to search for the correct satellite signals at
4. the correct signal parameters Correct initialization parameters will enable the receiver to acquire signals more quickly and thus produce a faster navigational solution When a valid Navigation Initialization command is received the receiver will restart using the input parameters as a basis for satellite selection and acquisition Format PSRF101 lt X gt lt Y gt lt Z gt lt CIkOffset gt lt TimeOfWeek gt lt WeekNo gt lt chnlCount gt lt ResetCfg gt CKSUM lt CR gt lt LF gt lt X gt X coordinate position INT32 lt Y gt Y coordinate position INT32 lt Z gt Z coordinate position INT32 lt CIkOffset gt Clock offset of the receiver in Hz Use O for last saved value if available If this is unavailable a default value of 75000 for GSP1 95000 for GSP 1 LX will be used INT32 lt TimeOf Week gt GPS Time Of Week UINT32 lt WeekNo gt GPS Week Number UINTI6 Week No and Time Of Week calculation from UTC time lt chnlCount gt Number of channels to use 1 12 If your CPU throughput is not high enough you could decrease needed throughput by reducing the number of active channels 13 UBYTE lt ResetCfg gt bit mask 0x01 Data Valid warm hotstarts 1 0x02 clear ephemeris warm start 1 0x04 clear memory Cold start 1 UBYTE Example Start using known position and time O PSRF101 2686700 4304200 385 1624 96000 497260 921 12 3 7F C Set DGPS Port ID 102 Set PORT B parameters for DGPS input This command is
5. used to control Serial Port B that is an input only serial port used to receive RTCM differential corrections Differential receivers may output corrections using different communication parameters The default communication parameters for PORT B are 9600 Baud 8data bits 0 stop bits and no parity If a DGPS receiver is used which has different communication parameters use this command to allow the receiver to correctly decode the data When a valid message is received the parameters will be stored in battery backed SRAM and then the receiver will restart using the saved parameters Format PSRF102 lt Baud gt lt DataBits gt lt StopBits gt lt Parity gt CKSUM lt CR gt lt LF gt lt baud gt 1200 2400 4800 9600 19200 38400 lt DataBits gt 8 lt StopBits gt 0 1 lt Parity gt 0 None Odd 1 Even 2 Example Set DGPS Port to be 9600 8 N 1 O PSRF102 9600 8 1 0 12 14 D Query Rate Control ID 103 Query standard NMEA message and or set output rate This command is used to control the output of standard NMEA message GGA GLL GSA GSV RMC VTG Using this command message standard NMEA message may be polled once or setup for periodic output Checksums may also be enabled or disabled depending on the needs of the receiving program NMEA message settings are saved in battery backed memory for each entry when the message is accepted Format O PSRF103 lt msg gt lt mode gt lt rate gt lt cksumEnable gt CKSUM lt
6. 000knots max 3 3Vde 5 5Vdc Continuous mode 60mA typical Trickle power 25mA typical 2 5V to 3 6V 10uA typical lt Serial Port gt Ports one for GPS one for DGPS Electrical level TTL level Output voltage 0 2 85v Communication Full duplex asynchronous Code type ASCII GPS Protocol SiRF binary NMEA 0183 changeable Default NMEA GPS Function SiRF binary gt gt position velocity altitude status and control NMEA 0183 gt gt GGA GSA GSV RMC VTG and GLL are optional GPS transfer rate Software command setting Default 4800bps for NMEA DGPS protocol RTCM SC 104 ver 2 00 type 1 2 and 9 lt Time Mark gt 1 PPS Pulse Level TTL Pulse duration 100ms Time reference At the pulse positive edge Measurement Aligned to GPS sec lus lt Active Antenna Connector gt MMCX Environmental Characteristics lt Temperature gt Operating 40 deg C to 80 deg C Storage 40 deg C to 85 deg C Physical Characteristics COMPONENT SIDE lt 7 mm 14 875 mm 3mm itch 1 27mm WWU Cf E PCB TOP VIEW Interface Connection Pin out of the 12 pin interface connector Ries Name Description Type 1 VANT Antenna DC Voltage Input 2 VBAT Backup Battery Input 3 VDC 3 3V 5 5V DC Power Input Input 4 PBRES Push Button Reset Input Active Low Input 5 GPIO3 Reserved 6 TX
7. A Serial Data Output A GPS Data Output 7 RXA Serial Data Input A Command Input 8 TXB Reserved 9 RXB Serial Data Input B DGPS Data Input 10 SELECT Reserved 11 TIMEMARK 1PPS Time Mark Output Output 12 GND Ground Interface description VANT antenna DC power input DC voltage is for active antenna VDC DC power input This is the main DC supply for a 3 3V 5 5V power module board VBAT Backup battery This is the battery backup input that powers the SRAM and RTC when main power is 5 removed Typical current draw is 10uA Without an external backup battery the module engine board will execute a cold star after every turn on To achieve the faster start up offered by a hot or warm start a battery backup must be connected To maximize battery lifetime the battery voltage should be between 2 5v and 3 6v PBRES Push button reset This pin provides an active low reset input to the engine board It causes the engine board to reset and start searching for satellites SELECT Do not connect TXA This is the main transmits channel for outputting navigation and measurement data to user s navigation software or user written software Output TTL level OV 2 85V RXA This is the main receive channel for receiving software commands to the engine board from SiRFdemo software or from user written software Normally this pin must be kept in high and if you don t use this pin ple
8. User Manual GPS Receiver Engine Board MTI 2 1 lt lt Specificaton gt gt Product Features SiRF GPS Architecture SiRF starll high performance and low power consumption chip set Support standard NMEA 0183 protocol All in view 12 channel parallel processing SnapLock 100ms re acquisition time Cold start under 45 seconds average Superior urban canyon performance FoliageLock for weak signal tracking Full duplex RS 232 port for navigation and control messages Differential GPS capability through 2 RS 232 port System Specification Electrical Characteristics lt Receiver gt Frequency C A code Channels Sensitivity lt Accuracy gt Position Horizontal Velocity Time lt Datum gt WGS 84 lt Acquisition Rate gt Reacqusition Hot start Warm start Cold start lt Dynamic Condition gt Altitude Velocity lt Power gt Voltage supply Current supply Backup Power Backup Current L1 1575 42MHz 1 023MHz chip rate 12 175dBW 15m 2d RMS SA off 1 5 m WAAS EGNOS enable 0 1m sec 95 SA off Imicrosecond synchronized to GPS time 0 1 sec average recovery time for being interrupted 8 sec average with ephemeris and almanac valid 38 sec average with almanac but not ephemeris 48 sec average neither almanac nor ephemeris 18 000 meters 60 000 feet max 515 meters sec 1
9. ase connect a resistor to pull high TXB No function as so far Do not connect RXB This is the auxiliary receive channel for inputting differential corrections to the engine board to enable DGPS navigation Time mark This pin provides one pulse per second output from the engine board that is synchronized to GPS time GND GND provides the ground for the engine board Connect all grounds 2 SOFIWARE COMMAND 2 1 NMEA Output Command GGA Global Positioning System Fixed Data Table B 2 contains the values for the following example GPGGA 161229 487 3723 2475 N 12158 3416 W 1 07 1 0 9 0 M 0000 18 Table B 2 GGA Data Format Name Example Units Description Message ID GPGGA GGA protocol header UTC Time 161229 487 hhmmss sss Latitude 3723 2475 ddmm mmmm N S Indicator N N north or S south Longitude 12158 3416 dddmm mmmm E W Indicator W E east or W west Position Fix Indicator 1 See Table B 3 Satellites Used 07 Range 0 to 12 HDOP 1 0 Horizontal Dilution of Precision MSL Altitude 9 0 meters Units M meters Geoid Separation meters Units M meters Age of Diff Corr second Null fields when DGPS is not used Diff Ref Station ID 0000 Checksum 18 lt CR gt lt LF gt End of message termination 1 SiRF Technology Inc does not support geoid corrections Table B 3 Position Fix Indicator Values are WGS84 ellipsoid heights Value
10. ed to operate in 2D or 3D mode A 2Dautomatic allowed to automatically switch 2D 3D Table B 7 Mode 2 Value Description 1 Fix Not Available 2 2D 3 3D GSV GNSS Satellites in View Table B 8 contains the values for the following example GPGSV 2 1 07 07 79 048 42 02 51 062 43 26 36 256 42 27 27 138 42 71 GPGSV 2 2 07 09 23 313 42 04 19 159 41 15 12 041 42 41 Table B 8 GSV Data Format Name Example Description Message ID GPGSV GSV protocol header Number of Messages 2 Range 1 to 3 Message Number 1 Range to 3 Satellites in View 07 Satellite ID 07 Channel 1 Range to 32 Elevation 79 degrees Channel 1 Maximum90 Azimuth 048 degrees Channel 1 True Range 0 to 359 SNR C No 42 dBHz Range 0 to 99 null when not tracking Satellite ID 27 Channel 4 Range 1 to 32 Elevation 27 Degrees Channel 4 Maximum90 Azimuth 138 Degrees Channel 4 True Range 0 to 359 SNR C No 42 dBHz Range 0 to 99 null when not tracking Checksum 71 lt CR gt lt LF gt End of message termination 1 Depending on the number of satellites tracked multiple messages of GSV data may be required RMC Recommended Minimum Specific GNSS Data Table B 10 contains the values for the following example GPRMC 161229 487 A 3723 2475 N 12158 3416 W 0 13 309 62 120598 10 Table B 10 RMC Data Format Name Example Units Descripti
11. lt Lon gt Longitude position it is assumed positive east of Greenwich and negative west of Greenwich Float possibly signed lt Alt gt Altitude position float possibly signed lt ClkOffset gt Clock Offset of the receiver in Hz use O for last saved value if available If this is unavailable a default value of 75000 for GSP1 95000 for GSP1 LX will be used INT32 lt TimeOfWeek gt GPS Time Of Week UINT32 lt WeekNo gt GPS Week Number UINT16 lt ChannelCount gt Number of channels to use 1 12 UBYTE lt ResetCfg gt bit mask 0x01 Data Valid warm hot starts 1 0x02 clear ephemeris warm start 1 0x04 clear memory Cold start 1 UBYTE Example Start using known position and time O PSRF104 37 3875111 121 97232 0 96000 237759 922 12 3 37 16 F Development Data On Off ID 105 Switch Development Data Messages On Off Use this command to enable development debug information if you are having trouble getting commands accepted Invalid commands will generate debug information that should enable the user to determine the source of the command rejection Common reasons for input command rejection are invalid checksum or parameter out of specified range This setting is not preserved across a module reset Format PSRF105 lt debug gt CKSUM lt CR gt lt LF gt lt debug gt 0 Off 1 On Example Debug On O PSRF105 1 3E Example Debug Off O PSRF105 0 3F 17
12. on Message ID GPRMC RMC protocol header UTC Time 161229 487 hhmmss sss Status A A data valid or V data not valid Latitude 3723 2475 ddmm mmmm N S Indicator N N north or S south Longitude 12158 3416 dddmm mmmm E W Indicator W E east or W west Speed Over Ground 0 13 knots Course Over Ground 309 62 degrees True Date 120598 ddmmyy Magnetic Variation degrees E east or W west Checksum 10 lt CR gt lt LF gt End of message termination SiRF Technology Inc does not support magnetic declination All course over ground data are geodetic WGS48 directions 10 VTG Course Over Ground and Ground Speed GPVTG 309 62 T M 0 13 N 0 2 K 6E Name Example Units Description Message ID GPVTG VTG protocol header Course 309 62 degrees Measured heading Reference T True Course degrees Measured heading Reference M Magnetic Speed 0 13 knots Measured horizontal speed Units N Knots Speed 0 2 Km hr Measured horizontal speed Units K Kilometers per hour Checksum 6E lt CR gt lt LF gt End of message termination 11 2 2 NMEA Input Command A Set Serial Port ID 100 Set PORTA parameters and protocol This command message is used to set the protocol SiRF Binary NMEA or USER1 and or the communication parameters baud data bits stop bits parity Generally this command would be used to switch the module back to SiRF Binary protocol mode where a more extensive command message set is
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