Smiths Kelvin Hughes Nucleus 3 5000 Series, System Handbook

Page: 435 / 510

5.17. $—GGA Global Po si tioning Sys tem Fix Data
Message
Type
Port Maximum
Message
frequency
Minimum
message
frequency
Listener 1A, 2A, 3A, 4A 1 Hz 0.2 Hz
Time, position and fix related data for a GPS receiver.
1) GPS quality indicator: 0 = fix not available or
invalid
1 = GPS fix
2 = Differential GPS fix
3 = GPS PPS Mode GPS
fix valid
2) Time in seconds since last SC104 Type 1 or 9 update,
null field when DGPS is not used
3) Geoidal Separation: the difference between the
WGS-84 earth ellipsoid and mean-sea-level (geoid), “-” =
mean-sea-level below ellipsoid.
NOTES:
1. If a GGA message is received from the same
sensor as a GLL message, the GGA message is taken in
preference to the GLL message.
2. If a position sensor is lost for any reason, the
position will "time-out" after 20 seconds and the position
sensor in use is set to zero (no sensor) allowing any sensor
to provide position information.
July 03 8aA.6 Amdt 5
KH 2020
Chap 8a - Annex A
$--GGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh<CR><LF>
Checksum
Differential reference station ID 0000-1023
Age of differential GPS data2
Units of geoidal separation M=metres
Geoidal separation
Units of antenna altitude M=metres
Antenna altitude above/below mean-sea-level (geoid)
Horizontal dilution of precision
Number of satellites in use: 00-12, may be different from number of satellites
in view
GPS quality indicator
Longitude cardinal, E=East, W=West
Longitude
Latitude Cardinal, N=North, S=South
Longitude
UTC of position