Yo Hans! On Wed, 4 Mar 2026 21:38:04 +0100 Hans Mayer <[email protected]> wrote:
> On 04.03.26 00:04, Gary E. Miller wrote:
> > Just a start. A lot more you should do. Did you read the
> > unxtool-examples for the newer u-blox?
> Yes, I did, again.
> But didn't find much about Gen20. But most will also fit what
> described in Gen10.
Because I do not have a Gen20 yet. AFAIK, the Gen20 and Gen10
UBX are essentially the same. Gen9 was the watershed, it has the old
and new configuration. Gen10 and later, only the new style.
> When I opened xgps I was wondering when I saw the statistics.
> Wow, I see 100 satellites just in my sky, how much are there
> available around the world ?
Same, or more. The systems we see are mostly doing full earth orbits.
A few, the SBAS, are in geostationary orbit. On the backside of
earth you have the QZSS, and other sats, in "quasi stationary orbit".
So over China they get all we see, plus those.
> But then I counted the dots. And this is far away to be 100 sats
> seen. It's about 40 or more.
> So I tried to query the X20P with ubxtool statements.
Remember the definition of "seen". "seen" means the receiver has
the Almanac for that sat, and that sat is above the elevation mask.
For gpsd purposes, once a signal is actually locked, that is you have
and SNR, that PRN/sigid is one "seen". If a second band is also
received, it is another "seen".
> Counting with NAV-SAT was 45. Actually I did it with this method:
> ubxtool -p NAV-SAT | sed -n -e '/^UBX-NAV-SAT:/,/^$/ p' | awk -v RS=
> 'NR==1' | grep -c gnssId
You expect consistency? Nope. u-blox admits that various ways to
count "seen" and "used" will likely not match.
> Counting with NAV-SIG I got 102
> ubxtool -p NAV-SIG | sed -n -e '/^UBX-NAV-SIG:/,/^$/ p' | awk -v RS=
> 'NR==1' | grep -c gnssId
NAV-SAT and NAV-SIG do not do the sasme thing. Comparing Apples and
Oranges. NAV-SAT knows nothing of sigId.
> Of course I couldn't run all command at the same time stamp, so the
> results differ slightly.
That sats are no so fast that a few seconds matter.
> It seems what we see in the "GPS Data" area besides "Sats Seen" are
> the number of signals and not the sats.
Sort of.
> Obviously the same with "Sats Used".
Yes.
> P.S.: It's probably not only related to X20P, the same behaviour with
> F9P, but of course with different numbers.
Yes, Gen9, Gen10 and Gen9 all have the new style config. They differ
in what signals, and how many signals, they can receive.
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
[email protected] 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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