SkyTraq PX1120S - Page 14

14
SkyTraq Technology, Inc. Preliminary Draft www.skytraq.com.tw
GSA – GNSS DOP and Active Satellites
GNSS receiver operating mode, satellites used in the navigation solution reported by the GGA or GNS sentence and
DOP values.
Structure:
$GNGSA,A,x,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,x.x,x.x,x.x,x*hh<CR><LF>
1 2 3 3 3 3 3 3 3 3 3 3 3 3 4 5 6 7 8
Example:
$GNGSA,A,3,10,12,14,20,21,24,25,31,32,193,,,1.1,0.6,0.9,1*01<CR><LF>
$GNGSA,A,3,69,70,73,79,80,,,,,,,,1.1,0.6,0.9,2*3C<CR><LF>
$GNGSA,A,3,01,02,03,06,09,10,14,16,21,22,26,,1.1,0.6,0.9,4<CR><LF>
Field
Name
Example
Description
1
Mode
A
Mode
‘M’ = Manual, forced to operate in 2D or 3D mode
‘A’ = Automatic, allowed to automatically switch 2D/3D
2
Mode
3
Fix type
1 = Fix not available
2 = 2D
3 = 3D
3
Satellite used 1~12
10, 12, 14, 20,
21, 24, 25, 31,
32, 193
01 ~ 32 are for GPS; 33 ~ 64 are for WAAS (PRN minus 87); 193
~ 197 are for QZSS; 65 ~ 88 are for GLONASS (GL PRN) ; 01 ~ 36
are for GALILEO (GA PRN); 01 ~ 37 are for BDS (BD PRN). GPS,
GLONASS, GALILEO and BDS satellites are differentiated by the
GNSS system ID in table 3. Maximally 12 satellites are included
in each GSA sentence.
4
PDOP
1.1
Position dilution of precision (0.0 to 99.9)
5
HDOP
0.6
Horizontal dilution of precision (0.0 to 99.9)
6
VDOP
0.9
Vertical dilution of precision (0.0 to 99.9)
7
GNSS System ID
1
GNSS system ID
*
1 = GPS
2 = GLONASS
3 = GALILEO
4 = BDS
5 = IRNSS
8
Checksum
01
*GNSS System ID identifies the GNSS system ID according to Table 3.