128
DTM: Datum Reference
$GPDTM,s1,,f2,c3,f4,c5,f6,s7*cc
GBS: GNSS Satellite Fault Detection
$--GBS,m1,f2,f3,f4,d5,f6,f7,f8,h9,h10*cc
Parameter
Description
Range
s1
Local datum code:
• W84: WGS84 used as local datum
• 999: Local datum computed using the
parameters provided by the RTCM3.1
data stream.
W84, 999
f2
Latitude offset, in meters
0-59.999999
c3
Direction of latitude
N, S
f4
Longitude offset, in meters
0-59.999999
c5
Direction of longitude
E, W
f6
Altitude offset, in meters
±0-99.999
s7
Reference datum code
W84
*cc
Checksum
*00-*FF
Parameter
Description
Range
m1
UTC time of the GGA or GNS fix asso-
ciated with this message (hhmmss.ss)
000000.00-235959.99
f2
Expected error in latitude, in meters,
due to bias, with noise= 0
0.0-99.9
f3
Expected error in longitude, in meters,
due to bias, with noise= 0
0.0-99.9
f4
Expected error in altitude, in meters,
due to bias, with noise= 0
0.0-99.9
d5
ID number of most likely failed satellite
1-32 for GPS
33-64 for SBAS
65-96 for GLONASS
97-128 for Galileo
129-160 for BeiDou
193-202 for QZSS
f6
Probability of missed detection for
most likely failed satellite
0.00-1.00
f7
Estimate of bias, in meters, on most
likely failed satellite
0.0-99.9
f8
Standard deviation of bias estimate
0.0-99.9
h9
GNSS system ID
0-F
h10
GNSS signal ID
0-F
*cc
Checksum
*00-*FF
