Instruction manual

Page 18 Z-12 Real-Time Sensor Operation and Reference Manual
Ensure you enter these commands. The first command enables NMEA output port A while the third
one tells the Sensor to return GGA information through port A. The second one tells the NMEA
output rate every 1.0 sec. For more information about these commands, refer to Chapter 4,
Command Response Formats.
The response message is in NMEA 083 format with the structure:
$GPGGA,hhmmss.ss,ddmm.mmmmmm,s,dddmm.mmmmmm,s,n,
qq,pp.p,±hhhhh.hhh,M,,M,dd.ll,ssss
where the fields are as defined in Table 2.5.
Table 2.5: GGA Response Message Structure
Field Significance
hhmmss.ss Current UTC time of position computation in hours, minutes and seconds.
ddmm.mmmmmm Latitude component of position, in degrees, minutes and fraction of
minutes.
s GPS latitude N = North, S = South.
dddmm.mmmmmm GPS longitude in degrees, minutes and fraction of minutes.
s Longitude direction: E = east W = west
n GPS position quality indicator
n = 0 - GPS solution is not available
n = 1 - GPS autonomous position is available
n = 2 - RTCM differential or CPD differential available, solution accuracy at
submeter level
n = 3 - CPD differential available, solution accuracy at centimeter level
qq Number of SVs used in position computation 1 through 12
pp.p HDOP - horizontal dilution of precision 00.0 through 99.9
±hhhhh.hhh Antenna height above WGS84 ellipsoid -1000 through +18000
M Meters
dd (Differential only) Data link age of differential GPS data 0 through 99
seconds
.lll (CPD Differential only) If in carrier phase differential (CPD) rover mode,
the decimal is the solution latency in seconds. The field stays at 0.999 if the
latency is greater than 0.999. 0.0 through 0.999 milliseconds.
ssss Differential reference station ID (STID), 4-character string