[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: 2 separate positions pass through gpsd
From: |
Gary E. Miller |
Subject: |
Re: 2 separate positions pass through gpsd |
Date: |
Thu, 13 Oct 2022 11:08:48 -0700 |
Yo Filip!
On Thu, 13 Oct 2022 12:11:45 +0200
Filip Kubicz <filip.kubicz@tier.app> wrote:
> First of all, thank you for adding passing the control commands to the
> receiver through gpsd. It was really a big improvement and a
> simplification to our application!
Glad to help.
> I have a question:
> From 1 receiver, I need to pass 2 separate positions
> 1. final Dead Reckoning-computed position (GNRMC, GNGNS, PQTMINS and
> others) 2. GNSS-only position (coming from a receiver debug command
> PQTMGPS)
I'm confused. You skipped over a bunch of details. What GNSS recevier
sends PQTMINS or PQTMGPS
I know of know GNSS receiver that reports 2 different positions...
> These 2 might differ, and the position 1. might be very very wrong in
> some cases.
Sounds like a bug in the receiver.
> Chip supplier is working on improvements (Quectel LC29D),
Oh, Quectel. Good grief. Before the "improve" things they should fix
all their bugs.
> however I need to gather more data and be able to tell how big are
> differences, and for the time being add logic in the application that
> discards position 1. if it's too far away from the GNSS-only.
Every other DR receiver does that for you. Quectel should not make the
client do that.
> For the GNSS-only position, I tried to distinguish it by assigning it
> a different status - e.g. STATUS_SIM that will never be used in this
> application.
>
> The problem with using status field is that it is cached by gpsd.
gpsd does not cache anything.
> If
> there occurs a higher status in the beginning of the reporting cycle,
> it will be also used for all TPV reports in this cycle:
Got any documentation on this mess? I can do nothing until I have doc.
> Implementation of PQTMINS is here, if needed:
I'm not looking at code without doc.
Once you get this project doc, can you get me some working samples?
> I also tried using unused variables in the gps_fix_t struct, but this
> is also not a perfect solution, as wanglem and wangler get rounded:
We can add new variables in gps_fix_t if needed. But if you are getting
rounding errors on doubles, you got big problems.
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
pgpmkounszPHd.pgp
Description: OpenPGP digital signature