Re: $GPGGA / increased number of satellites

[Gary E. Miller]

Yo Hans!

On Sun, 5 May 2024 15:55:41 +0200
Hans Mayer <gpsd@ma.yer.at> wrote:

> Yesterday I updated gpsd from revision release-3.25-276-gcb8e4a5e4 (
> Tue Dec 12 23:55:08 2023 ) to the latest available revision 
> release-3.25-542-ge2333bb7c ( Fri May 3 17:00:50 2024 ).

Good, thanks for testing git head.

> Today I looked at the graphs I have and I realized that the number of 
> satellites increased dramatically. Before I did receive around 50 
> satellites ( maximum was 63 ) reported by $GPGGA records. Now the
> value is above 70 ( maximum is 82 ).

Yup.  Sats just keep multiplying like rabbits, and NMEA keeps changin to
support them.  And gpsd also has to support them, but since NMEA is a
closed standard, that only happens after we can examine the teat leaves.

> These are some lines before update:

Cherry picking data almost always leaves out what I really want to
see.  Your samples leave out what I want to see.  Thus I can
not point out to you want gpsd learned to read from the new NMEA
variants.

Please post full captures.

> I can't believe that during the 20 minutes of my update around 20 
> satellites were brought into the orbit.

But, beleive the the new gpsd got smarte at decoding the data that
you always had.

> In both cases ( before and after update ) I receive data from qzss, 
> sbas, glonass, gps, beidou and galileo.

Good.  As expected.

What you did not notice is that the number of satellites did not
increase, but the number of satellite/signal pairs increased because
u-blox had failed to document that until recently.

By signal, I mean: L1, L2, L5, B2, etc.

You can see this using cgps, or xgps.

> My environment: I am still running U-blox ZED-F9P with version 27.12
> and the gps antenna is unchanged and fix mounted on  the top of my
> roof since long time.

Good.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  Tel:+1 541 382 8588

            Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin

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