NMEA-GN-GSA

Description:

Standard NMEA: GNSS DOP and active satellites.

Configuration:

NMEA-GN-GSA_GNSS for combined (average) output from both receivers
- Operation and navigation modes are taken from the “best” receiver
- The list of satellite IDs contains the union of satellites used by GNSS1 and GNSS2
- The PDOP, HDOP and VDOP are the averages of the respective values of the two receivers
NMEA-GN-GSA_GNSS1 for output from GNSS 1 receiver
- This is the standard NMEA GSA for GNSS1.
NMEA-GN-GSA_GNSS2 for output from GNSS 2 receiver
- This is the standard NMEA GSA for GNSS2.
NMEA-GN-GSA_FUSION for output from Fusion
- Operation and navigation modes are taken from the “best” receiver
- The list of satellite IDs contains the union of satellites used by GNSS1 and GNSS2
- The PDOP, HDOP and VDOP are the averages of the respective values of the two receivers

Notes:

These messages does not contain any information that would let one tell them apart. Do not enable more than one of these in the same port.
This message is according to NMEA 0183 v4.11 (and erratas).
This message uses the “GN” talker ID and NMEA v4.11 satellite numbering.

Example messages (one epoch):

CODE

$GNGSA,A,3,04,06,07,09,11,16,20,30,,,,,0.98,0.49,0.85,1*0A\r\n
$GNGSA,A,3,67,68,69,76,77,78,83,84,,,,,0.98,0.49,0.85,2*0A\r\n
$GNGSA,A,3,02,03,07,08,13,15,25,26,,,,,0.98,0.49,0.85,3*09\r\n
$GNGSA,A,3,09,14,24,26,27,28,33,,,,,,0.98,0.49,0.85,4*04\r\n

Message fields:

#	Field	Format	Unit	Nullable	Example	Description
1	`mode_op`	Character	-	N	`A`	Operation mode: always `A` (automatic, allowed to automatically switch 2D/3D)
2	`mode_nav`	Integer	-	N	`1`	Navigation mode: `1` (fix not available), `2` (2D) or `3` (3D)
3..14	`ids`	Integer	-	Y	`01,03,15`	ID numbers of satellites used in solution. See the NMEA 0183 version 4.11 standard document.
15	`pdop`	Float (.2)	-	Y	`1.2`	Position dillution of precision
16	`hdop`	Float (.2)	-	Y	`1.2`	Horizontal dillution of precision
17	`vdop`	Float (.2)	-	Y	`1.2`	Vertical dillution of precision
18	`gnss_id`	Integer	-	Y	`1`	GNSS system ID: `1` (GPS, SBAS), `2` (GLONASS), `3` (Galileo), `4` (BeiDou), `5` (QZSS)