Re: GPSD does not see Galileo

[David Taylor]

On 21/01/2021 18:38, Gary E. Miller wrote:
> Yo David!
>
> On Thu, 21 Jan 2021 17:01:18 +0000
> David Taylor<gm8arv@yahoo.co.uk>  wrote:
>
> > Compiled cgps: 3.22.1~dev (revision release-3.22-46-gc36433084) and
> > all seems to be running OK, with one exception - I can't get Galileo
> > to work!
> Works for me.  Are you sure your antenna is rated for Galileo?
>
> > I'm using the same hardware and GPS/RTC device as before (a
> > second set), and whilst I can use ubxtool to enable and disable
> > GLONASS (for example), the same commands don't appear to work for
> > GALILEO.  I'm puzzled because ubxtool seems to think it's enabled if
> > I'm reading the output correctly:
> >
> > UBX-CFG-GNSS:
> >    msgVer 0  numTrkChHw 32 numTrkChUse 32 numConfigBlocks 7
> >     gnssId 0 TrkCh  8 maxTrCh 16 reserved 0 Flags x01010001
> >      GPS L1C/A enabled
> >     gnssId 1 TrkCh  1 maxTrCh  3 reserved 0 Flags x01010001
> >      SBAS L1C/A enabled
> >     gnssId 2 TrkCh  4 maxTrCh  8 reserved 0 Flags x01010001
> >      Galileo E1 enabled
> >     gnssId 3 TrkCh  8 maxTrCh 16 reserved 0 Flags x01010000
> >      BeiDou B1I
> >     gnssId 4 TrkCh  0 maxTrCh  8 reserved 0 Flags x03010000
> >      IMES L1
> >     gnssId 5 TrkCh  0 maxTrCh  3 reserved 0 Flags x05010001
> >      QZSS L1C/A enabled
> >     gnssId 6 TrkCh  8 maxTrCh 14 reserved 0 Flags x01010001
> >      GLONASS L1 enabled
> Yes, that is Galileo enabled.  You may need 30 minutes after enabling Galileo
> to see any.
>
> > Full output attached.
> Looks good, except no Galileo.
>
> > I've left it running for many minutes, enough for a full almanac
> > download.
> So "many" > 30 mins?
>
> > The antenna is a standard one, working on GPS and GLONASS.
> Uh, not good enough.  Galileo has the same center frequency as
> GPS, but has a wider bandwidth than GPS.  So the "better" antennas
> that filter for GPS actually filter out Galileo.
>
> > I've used ubxtool reset, power resets.  What am I missing?
> Probably the antenna is your issue.
>
> RGDS
> GARY

Yes, Gary, it could be the antenna, although I've not seen this effect 
before.  However, after about 90 minutes of running the Galileo suddenly 
appeared.  I didn't think it should take that long, though.  Fewer 
active satellites, though....

I've noticed before though that on other installations the number of 
available satellites can suddenly drop, and then reappear a few hours or 
more later.  This could be explained by the time taken to get the full 
almanac, after the ephemeris times out.  I would have thought that the 
orbital data should be transmitted in a more robust manner, but needing 
a much greater signal for cold-start acquisition suggests it's not.

So nothing wrong with the configuration, but using an indoor antenna has 
its issues!  Something learnt!

Cheers,
David
--
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Email: david-taylor@blueyonder.co.uk
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