Re: AW: Decreasing number of used satellites

[Greg Troxel]

"Wielant, Ulrich" <U.Wielant@leonardogermany.com> writes:

> Gpsd version: 3.23.1 (I am using the opensuse 15.2 gpsd package)

Gary said there has been a lot of multiconstellation NMEA improvements.
So you should update to recent git sources.

> NMEA version: don't know - have to ask Garmin but that takes time. I
> guess it's < 4.11.

I guess you have to wait.  It's amazing that a receiver like this
doesn't document that in the manual.

> I managed to configure the GPS so that only GPS satellites are used and no 
> other systems like GLONASS, QZSS etc.
> So all GSA and GSV messages should only report GPS PRNs.

That's good to simplify.

Reporting 26 twice seems like a bug you should report to Garmin.  (You
should have even stronger expectations of support from proprietary
software :-)

There is GPGSA and GNGSA, separately from GNGSA having only GPS.  But
your receiver appers to flip to GPGSA.

> With satellites used=false I see:
> gpsd:IO: <= GPS: 
> $GPGSV,2,1,06,05,20,046,43,16,50,298,44,18,71,111,45,23,14,144,39*7F
> gpsd:PROG: NMEA0183: xPGSV: part 1 of 2, last_gsv_talker '0'  last_gsv_sigid 0
> gpsd:PROG: NMEA0183: xPGSV: new part 1, last_gsv_talker '0', zeroing
> gpsd:PROG: NMEA0183: xxGSV: Partial satellite data (1 of 2).
> gpsd:PROG: NMEA0183: GPGSV is just after a cycle ender.
> gpsd:IO: <= GPS: $GPGSV,2,2,06,26,75,244,46,27,21,268,43*74
> gpsd:PROG: NMEA0183: xPGSV: part 2 of 2, last_gsv_talker '0x50'  
> last_gsv_sigid 0
> gpsd:PROG: NMEA0183: GPGSV is just after a cycle ender.
> gpsd:INFO: Sats used (0):
> gpsd:PROG: Changed mask: {ONLINE|SATELLITE|PACKET} with reliable cycle 
> detection
>
> With satellites used=true I see:
> gpsd:IO: <= GPS: 
> $GPGSV,2,1,06,05,20,046,44,16,50,298,45,18,71,112,45,23,14,144,38*7B
> gpsd:PROG: NMEA0183: xPGSV: part 1 of 2, last_gsv_talker '0'  last_gsv_sigid 0
> gpsd:PROG: NMEA0183: xPGSV: new part 1, last_gsv_talker '0', zeroing
> gpsd:PROG: NMEA0183: xxGSV: Partial satellite data (1 of 2).
> gpsd:PROG: NMEA0183: GPGSV is just after a cycle ender.
> gpsd:IO: <= GPS: $GPGSV,2,2,06,26,75,245,47,27,21,268,43*74
> gpsd:PROG: NMEA0183: xPGSV: part 2 of 2, last_gsv_talker '0x50'  
> last_gsv_sigid 0
> gpsd:PROG: NMEA0183: GPGSV is just after a cycle ender.
> gpsd:INFO: PRN  5 az  46.0 el 20.0 ( 0.675958,  0.652765,  0.342020)
> gpsd:INFO: PRN 16 az 298.0 el 50.0 (-0.567548,  0.301771,  0.766044)
> gpsd:INFO: PRN 18 az 112.0 el 71.0 ( 0.301862, -0.121960,  0.945519)
> gpsd:INFO: PRN 23 az 144.0 el 14.0 ( 0.570326, -0.784986,  0.241922)
> gpsd:INFO: PRN 26 az 245.0 el 75.0 (-0.234570, -0.109382,  0.965926)
> gpsd:INFO: PRN 27 az 268.0 el 21.0 (-0.933012, -0.032581,  0.358368)
> gpsd:INFO: Sats used (6):
> gpsd:PROG: Changed mask: {ONLINE|DOP|SATELLITE|PACKET} with reliable cycle 
> detection

> Do you see what makes the difference between gpsd reporting satellites as 
> used and not as used?

No, I don't.  Get the latest sources from git, build them yourself, and
run the debugger or add more debug statements.  And read the code of
course.  It may be that it is fusing GSA for used with GSV for CNR.
If you don't want to debug it yourself you probably need a consultant.

You still haven't provided a full log of NMEA not with gpsd.

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