NMEA-0183 message: GGA

Time, position, and fix related data

An example of the GBS message string is:

$GPGGA,172814.0,3723.46587704,N,12202.26957864,W,2,6,1.2,18.893,M,-25.669,M,2.0 0031*4F

NOTE – The data string exceeds the NMEA standard length.

GGA message fields

Field Meaning
0 Message ID $GPGGA
1 UTC of position fix
2 Latitude
3 Direction of latitude:

N: North
S: South

4 Longitude
5 Direction of longitude:

E: East
W: West

6 GPS Quality indicator:

0: Fix not valid
1: GPS fix
2: Differential GPS fix (DGNSS), SBAS, OmniSTAR VBS, Beacon, RTX in GVBS mode
3: Not applicable
4: RTK Fixed, xFill
5: RTK Float, OmniSTAR XP/HP, Location RTK, RTX
6: INS Dead reckoning

7 Number of SVs in use, range from 00 through to 24+
8 HDOP
9 Orthometric height (MSL reference)
10 M: unit of measure for orthometric height is meters
11 Geoid separation
12 M: geoid separation measured in meters
13 Age of differential GPS data record, Type 1 or Type 9. Null field when DGPS is not used.
14 Reference station ID, range 0000 to 4095. A null field when any reference station ID is selected and no corrections are received. See table below for a description of the field values.
15 The checksum data, always begins with *

NOTE – If a user-defined geoid model, or an inclined plane is loaded into the receiver, then the height output in the NMEA GGA string is always the orthometric height (height above a geoid). The orthometric height is output even if no user-defined geoid is loaded (there is a simplified default geoid in the receiver), or if a user-defined geoid is loaded, or if an inclined plane is used.

When using one of the MSS (Mobile Satellite Services), the Reference Station ID field indicates the following services:

Reference Station ID Service
0002 CenterPoint or ViewPoint RTX
0005 RangePoint RTX
0006 FieldPoint RTX
0100 VBS
1000 HP
1001 HP/XP (Orbits)
1002 HP/G2 (Orbits)
1008 XP (GPS)
1012 G2 (GPS)
1013 G2 (GPS/GLONASS)
1014 G2 (GLONASS)
1016 HP/XP (GPS)
1020 HP/G2 (GPS)
1021 HP/G2 (GPS/GLONASS)