NMEA
$GPGGA,202530.00,5109.0262,N,11401.8407,W,5,40,0.5,1097.36,M,-17.00,M,18,TSTR*61
The NMEA (National Marine Electronics Association) has defined standards that specify how electronic equipment for marine users communicate. GNSS receivers are part of this standard and the NMEA has defined the format for several GNSS data logs otherwise known as 'sentences'.
Each NMEA sentence begins with a '$' followed by a two-letter prefix identifying the type of sending device (for example 'GP', 'GL' or ‘GN’), followed by a sequence of letters that define the type of information contained in the sentence. Data contained within the sentence is separated by commas and the sentence is terminated with a two digit checksum followed by a carriage return/line feed. Here is an example of a NMEA sentence describing time, position and fix related data:
$GPGGA,134658.00,5106.9792,N,11402.3003,W,2,09,1.0,1048.47,M,-16.27,M,08,AAAA*60
The GPGGA sentence shown above and other NMEA logs are output the same no matter what GNSS receiver is used, providing a standard way to communicate and process GNSS information. For more information about NMEA, see the NMEATALKER command.
|
Field |
Structure |
Description |
Symbol |
Example |
|
1 |
$GPGGA |
Log header |
|
$GPGGA |
|
2 |
utc |
UTC time status of position (hours/minutes/seconds/ decimal seconds) |
hhmmss.ss |
202134.00 |
|
3 |
lat |
Latitude (DDmm.mm) |
llll.ll |
5106.9847 |
|
4 |
lat dir |
Latitude direction (N = North, S = South) |
a |
N |
|
5 |
lon |
Longitude (DDDmm.mm) |
yyyyy.yy |
11402.2986 |
|
6 |
lon dir |
Longitude direction (E = East, W = West) |
a |
W |
|
7 |
quality |
refer to Table: GPS quality indicators |
x |
1 |
|
8 |
# sats |
Number of satellites in use. May be different to the number in view |
xx |
10 |
|
9 |
hdop |
Horizontal dilution of precision |
x.x |
1.0 |
|
10 |
alt |
Antenna altitude above/below mean sea level |
x.x |
1062.22 |
|
11 |
a-units |
Units of antenna altitude (M = metres) |
M |
M |
|
12 |
undulation |
Undulation - the relationship between the geoid and the WGS84 ellipsoid |
x.x |
-16.271 |
|
13 |
u-units |
Units of undulation (M = metres) |
M |
M |
|
14 |
age |
Age of correction data (in seconds) The maximum age reported here is limited to 99 seconds. |
xx |
(empty when no differential data is present) |
|
15 |
stn ID |
Differential base station ID |
xxxx |
(empty when no differential data is present) |
|
16 |
*xx |
Check sum |
*hh |
*48 |
|
17 |
[CR][LF] |
Sentence terminator |
|
[CR][LF] |
GPS quality indicators
|
Indicator |
Description |
|
0 |
Fix not available or invalid |
|
1 |
Single point |
|
Converging PPP (TerraStar-L) |
|
|
2 |
Pseudorange differential |
|
Converged PPP (TerraStar-L) |
|
|
Converging PPP (TerraStar-C PRO, TerraStar-X) |
|
|
4 |
RTK fixed ambiguity solution |
|
5 |
RTK floating ambiguity solution |
|
Converged PPP (TerraStar-C PRO, TerraStar-X) |
|
|
6 |
Dead reckoning mode |
|
7 |
Manual input mode (fixed position) |
|
8 |
Simulator mode |
|
9 |
WAAS (SBAS)1 |
No comments to display
No comments to display