13 - SatGen Appendix
GGA NMEA format
Define the dynamic profile using a GGA NMEA formatted text message. The GGA format is shown below. SatGen will properly handle the UTC midnight rollover if it exists in the NMEA input file.
GGA NMEA Format Definition
$--GGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,xxx*hh<CR><LF>
hhmmss.ss – UTC of position
lll.ll,a – Latitude –N/S
yyyyy.yy,a – Longitude – E/W
x – GPS Quality indicator – Shall not be a null field
0 – Fix not available or invalid
1 – GPS SPS Mode, fix valid
2 – Differential GPS, SPS Mode, fix valid
3 – GPS PPS Mode, fix valid
4 – Real Time Kinematic. Satellite system used in RTK mode, fixed integers
5 – Float RTK. Satellite system used in RTK mode, floating integers
6 – Estimated (dead reckoning) Mode
7 – Manual Input Mode
8 – Simulator Mode
xx – Number of satellites in use (00-12) may be different from number in view
x.x – HDOP
x.x, M- Altitude, Mean-sea-level (geoid), meters
x.x,M – Geoidal separation, meters
Geoidal Separation: the difference between the WGS-84 earth ellipsoid surface and mean-sea-level (geoid) surface, “-“ = mean-sea-level surface below WGS-84 ellipsoid surface
x.x – Age of Differential GPS data
Time in seconds since last SC104 Type 1 or 9 update, null field when DGPS is not used
xxxx – Differential reference station ID, 0000-1023
Example GGA Data File
$GPGGA,212331.00,3902.9511,N,10451.2682,W,8,00,0.0,2057.8,M,-15.5,M,,*68
$GPGGA,212332.00,3902.9531,N,10451.2694,W,8,00,0.0,2058.6,M,-15.5,M,,*6F
$GPGGA,212333.00,3902.9548,N,10451.2718,W,8,00,0.0,2059.0,M,-15.5,M,,*62
$GPGGA,212334.00,3902.9559,N,10451.2750,W,8,00,0.0,2059.0,M,-15.5,M,,*69
$GPGGA,212335.00,3902.9565,N,10451.2786,W,8,00,0.0,2059.0,M,-15.5,M,,*6C