Yo Hans!
On Fri, 21 Nov 2025 23:04:28 +0100
Hans Mayer<[email protected]> wrote:
So I decided I give it a try again after years.
My environment is an U-BLOX ZED-F9P (PROTVER=27.12)
with an antenna HAB-ANN-MB-00-00 fix mounted on the top of the roof
of my house.
Which F9P model? L1/L2, or L1/L5. With or without SBAS?
Did you verify the correct signals were enabled. As in:
ubxtool -g CFG-SIGNAL
https://gpsd.io/ubxtool-examples.html#_checking_constellations_gen9
Got the dynamic model set to fixed? Like this:
ubxtool -g CFG-NAVSPG-DYNMODEL,0
https://gpsd.io/ubxtool-examples.html#_gen9_7
I did run twice a measurement as described in example 1 of the man
page. The first with 12 hours 46 min and the second with 12 hours.
This was the command line I used:
gpsrinex -i 30 -n 1440 --ant_num 2 --observer mayer --ant_type
HAB-ANN-MB-00-00 localhost:gpsd:/dev/serial0
Looks good. But the ant-type is not one of the "official" choices.
When I got the first result I was impressed.
I got a 95% sigma of 12 mm for lat and 10 mm for long.
So I started a second run with 12 hours.
There I got 15 mm and 22 mm as result of sigma. Not so bad I thought.
But then I calculated the distance between this two geolocations.
And the result was disillusioning. The distance is 164 mm , far away
of this 95% sigma.
Wow. First I have heard of anyone doing that. Disappointing. I'll
have to give that a try, I nevver thought to compare two runs.
About 2 years ago I tried to find the accurate position by averaging.
I run 12 times 24 hours measurements.
When I calculate the distance between this result and the gpsrinex
result I get more than half a meter.
So I am not sure what I should believe what is true and what is wrong.
"A man with more than one watch never knows what time it is."
There is a USGS benchmark near me, for a long time I thgouht I should
run a test with my antenna over the known position. Uh, oh. Looking
at that benchmark, it does not have any accuracy specified...
And there is another question.
At the Canadian PPP service I read now they support GLONASS and
Galileo too.
So they say. Did not work for me last time I tried.
So I left both systems in the config enabled. But the final report
didn't list them.
Dunno what's with that. I have emailed them a few times. But the
operators have zero clue as to what the program they run actually
does.
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
