GPS 18 Technical Specifications (190-00307-00) Rev. DPage 134.1.2 Sensor Initialization Information (PGRMI)The $PGRMI sentence provides information used to initialize the GPS sensor’s set position and time usedfor satellite acquisition. Receipt of this sentence by the GPS sensor causes the software to restart thesatellite acquisition process. If there are no errors in the sentence, it will be echoed upon receipt. If an erroris detected, the echoed PGRMI sentence will contain the current default values. Current PGRMI defaults(with the exception of the Receiver Command, which is a command rather than a mode) can also beobtained by sending $PGRMIE to the GPS sensor.$PGRMI,<1>,<2>,<3>,<4>,<5>,<6>,<7>*hh<1> Latitude, ddmm.mmm format for GPS 18 PC/LVC; ddmm.mmmmm format for GPS 18-5Hz (leading zeros must be transmitted)<2> Latitude hemisphere, N or S<3> Longitude, ddmm.mmm format for GPS 18 PC/LVC; ddmm.mmmmm format for GPS 18-5Hz (leading zeros must be transmitted)<4> Longitude hemisphere, E or W<5> Current UTC date, ddmmyy format<6> Current UTC time, hhmmss format for GPS 18 PC/LVC; hhmmss.s format for GPS 18-5Hz<7> Receiver Command, A = Auto Locate, R = Unit Reset4.1.3 Sensor Configuration Information (PGRMC)The $PGRMC sentence provides information used to configure the GPS sensor’s operation. Configurationparameters are stored in non-volatile memory and retained between power cycles. The GPS sensor willecho this sentence upon its receipt if no errors are detected. If an error is detected, the echoed PGRMCsentence will contain the current default values. Current default values can also be obtained by sending$PGRMCE to the GPS sensor.$PGRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>*hh<1> Fix mode, A = automatic, 2 = 2D exclusively (host system must supply altitude),3 = 3D exclusively<2> Altitude above/below mean sea level, -1500.0 to 18000.0 meters<3> Earth datum index. If the user datum index (96) is specified, fields <4> through <8> mustcontain valid values. Otherwise, fields <4> through <8> must be null. Refer to Appendix A:Earth Datum List for a list of earth datum and the corresponding earth datum index.<4> User earth datum semi-major axis, 6360000.000 to 6380000.000 meters (.001 metersresolution)<5> User earth datum inverse flattening factor, 285.0 to 310.0 (10-9 resolution)<6> User earth datum delta x earth centered coordinate, -5000.0 to 5000.0 meters (1 meterresolution)<7> User earth datum delta y earth centered coordinate, -5000.0 to 5000.0 meters (1 meterresolution)<8> User earth datum delta z earth centered coordinate, -5000.0 to 5000.0 meters (1 meterresolution)<9> Differential mode, A = automatic (output DGPS data when available, non-DGPS otherwise), D= differential exclusively (output only differential fixes)<10> NMEA 0183 Baud rate, 1 = 1200, 2 = 2400, 3 = 4800, 4 = 9600, 5 = 19200, 6 = 300, 7 = 600,8 = 38400 (for GPS 18-5Hz only)<11> Velocity filter, 0 = No filter, 1 = Automatic filter, 2–255 = Filter time constant(for example, 10 = 10 second filter)<12> Measurement Pulse Output, 1 = Disabled, 2 = Enabled<13> Measurement Pulse Output pulse length, (n+1)*20 msFor 18 LVC/PC n = 0 through 48 (max. 980 ms)For GPS 18-5Hz n = 0 through 8 (max. 180 ms)Example: n = 4 corresponds to a 100 ms wide pulse<14> Dead reckoning valid time 1 to 30 sec. for the GPS 18 PC/LVCor 0.2 to 30.0 sec. for the GPS 18-5HzAll configuration changes take effect after receipt of a valid value except baud rate and Measurement PulseOutput mode. Baud rate and Measurement Pulse Output mode changes take effect on the next power cycleor an external reset event.
