NMEA-0183 message: GSA

GPS DOP and active satellites

An example of the GSA message string is:

$GNGSA,A,3,21,5,29,25,12,10,26,2,,,,,1.2,0.7,1.0*27

$GNGSA,A,3,65,67,80,81,82,88,66,,,,,,1.2,0.7,1.0*20

GSA message fields

Field Meaning
0 Message ID $GNGSA
1 Mode 1:

M = Manual
A = Automatic

2 Mode 2: Fix type:

1 = not available
2 = 2D
3 = 3D

3 PRN number:

01 to 32 for GPS
33 to 64 for SBAS
64+ for GLONASS

4 PDOP: 0.5 to 99.9
5 HDOP: 0.5 to 99.9
6 VDOP: 0.5 to 99.9
7 The checksum data, always begins with *

If NMEA-0183 version 4.10 is selected, the 7th and 8th fields become:

Field Meaning

7

System ID based on:

GPS 1
GLONASS 2
Galileo 3
BeiDou 4
QZSS 0
8 The checksum data, always begins with *