Trimble Outdoors SPSX51 - Manual (Page 123)

SPSx51 Modular GPS Receivers User Guide 121
NMEA-0183 Output A
GSA GPS DOP and active satellites
An example of the GSA message string is shown below. Table A.2 describes the
message fields.
$GPGSA,<1>,<2>,<3>,<3>,,,,,<3>,<3>,<3>,<4>,<5>,<6>*<7>
Table A.2 GSA message fields
Field Meaning
0 Message ID $GPGSA
1 Mode 1, M = manual, A = automatic
2 Mode 2, Fix type, 1 = not available, 2 = 2D, 3 = 3D
3 PRN number, 01 through 32, of satellite used in solution, up to 12 transmitted
4 PDOP-Position dilution of precision, 0.5 through 99.9
5 HDOP-Horizontal dilution of precision, 0.5 through 99.9
6 VDOP-Vertical dilution of precision, 0.5 through 99.9
7 The checksum data, always begins with *