Yo David!
On Thu, 21 Jan 2021 19:48:38 +0000
David Taylor<gm8arv@yahoo.co.uk> wrote:
Yes, Gary, it could be the antenna, although I've not seen this
effect before.
Ditto. The receiver tries the eassy sats first, then tries to get
the ones with bad SNR. What is the SNR you see?
I didn't think it should take that long,
though. Fewer active satellites, though....
"active" does not compute. You mean "used"? That is normal. You set
your receiver to only track 4, and the reduce, or different, accuracy
that GPS means they get readily rejected.
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.
Not sure "what "available" means. Also, look at your UBX-CFG-GNSS
again, you have a lot of control over how many are "tracked". You have
more total maxTrCh, than your receiver has numTrkChHw, so the receiver
has to trhough things out often.
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.
More rubust with the proper antenna. Less robust with a GPS only, or
GPS/GLONASS only antenna.
So nothing wrong with the configuration, but using an indoor antenna
has its issues! Something learnt!
I'm not ready to say "nothing wrong".
RGDS
GARY