5.2 LD8 output sentences
5.2.2 GGA sentence
The NMEA GGA sentence contains time and position fix related data for a GPS system. It includes basic
quality information, which is limited to ‘Fix Quality’, ‘Number of Satellites in Use’, ‘HDOP’ and ‘Age of
Corrections’.
GGA sentence structure & example
$GPGGA, hhmmss.ss, ddmm.mmmmm, a, dddmm.mmmmm, b, q, xx, p.p, a.b, >M, c.d, M, x.x, nnnn *hh
$GPGGA, 123519.00, 4807.03787, N, 01131.00547, E, 1, 15, 0.9, 545.4, M, 46.9, M, 14.0, 0281 *47
GGA sentence defined
Field Content
GGA Global Positioning System Fix data
hhmmss.ss UTC of position
ddmm.mmmmm Latitude of position
a N or S, latitude hemisphere
dddmm.mmmmm Longitude of position
b E or W, longitude hemisphere
q
GPS Quality indicator (0 = invalid, 1 = GPS SPS, 2 = DGNSS fix, 4 = Fixed RTK, 5 =
Float RTK / PPP, 6 = Dead Reckoning), 7 = Manual Input Mode, 8 = Simulation
Mode
xx Number of satellites in use
p.p HDOP (Horizontal dilution of precision)
a.b Antenna altitude above/below mean-sea-level
M Units of antenna altitude, meters
c.d The relationship between the geoid and the WGS84 ellipsoid
M Units of meters
x.x Age of differential GNSS data
nnnn Differential reference station ID, 0000 to 1023
*hh Checksum
[CR][LF] Sentence Terminator
NOTE
The number of decimal places in the GGA message Latitude and Longitude values
is configurable, see section Setting GGA precision selection via terminal for details.
If making changes from five decimal places the sentence will no longer conform
with NMEA v3.01.
41
LD8 Operations Manual
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