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Re: Questions about decoding subframe messages (ublox F9P)
From: |
Gary E. Miller |
Subject: |
Re: Questions about decoding subframe messages (ublox F9P) |
Date: |
Fri, 22 May 2020 10:45:06 -0700 |
Yo Curtis!
On Fri, 22 May 2020 10:08:33 -0500
Curtis Olson <address@hidden> wrote:
> First; what am I trying to do? The long term target is to develop a
> tightly integrated kalman filter for attitude and location
> estimation.
Good luck with that, certainly the highway you the hard way.
> We would like to run multiple instances of our filter on
> different subsets of satellites. All the work we do in our lab is
> published under the MIT open-source license.
Where?
> By my understanding,
> this project will require knowing satellite orbital information,
> locations, etc., and (by my understanding) this requires reading and
> parsing subframe messages.
Require the orbital info? Yes. From subframe messages? No, many
sources for that info.
Without details no way to sugggest options.
> We have a ublox F9P receiver up and running here. I have it setup to
> output the following messages: NAV-PVT, UBX-RXM-RAWX, and
> UBX-RXM-SFRBX.
Send here the output of this, so we can see what you have:
ubxtool --p STATUS -p CONFIG
> I telnet'd to the gpsd daemon and ran a manual WATCH command with raw
> enabled and I am seeing the raw subframe messages (class=0x02,
> id=0x13) in the stream, so gpsd is at least seeing/receiving the
> RXM-SRFBX messages from the ublox F9P.
Good. BUt only first step in a long journey.
> I see the gpsd code has subframe.c which looks like it knows how to
> parse the subframe messages. I see lots of patches in the gpsd-dev
> list related to subframe parsing fixes.
Yeah, much of it. We dont know of many users of those messages
so there will be bungs in there.
> But so far, I haven't figured out if there is a mechanism to connect
> this all up in gpsd?
You don't. Your gpsd is doing exactly what it needs to do as a daemon.
You effort will be as a client. Look at the gpsd clients, obviously
influenced by your programming language of choice.
> Is there a way to coax gpsd into parsing my
> subframes and extracting all the values for me?
As you say, it already does that.
> How would I ask for
> the values back from gpsd?
Easy way to start:
gpspipe -w
Have you looked at RTKLIB? Or some of the other "soft gnss" projects?
They take the raw + orbital and generate fixes.
This may also be interesting to you:
https://www.researchgate.net/profile/Boonsap_Witchayangkoon3/publication/34767912_Elements_of_GPS_precise_point_positioning/links/0a85e53b5254fd136a000000.pdf
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
address@hidden Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can't measure it, you can't improve it." - Lord Kelvin
pgpise3Cb5h3z.pgp
Description: OpenPGP digital signature
- Questions about decoding subframe messages (ublox F9P), Curtis Olson, 2020/05/22
- Re: Questions about decoding subframe messages (ublox F9P),
Gary E. Miller <=
- Re: Questions about decoding subframe messages (ublox F9P), Curtis Olson, 2020/05/22
- Re: Questions about decoding subframe messages (ublox F9P), Gary E. Miller, 2020/05/22
- Re: Questions about decoding subframe messages (ublox F9P), Gary E. Miller, 2020/05/22
- Re: Questions about decoding subframe messages (ublox F9P), Curtis Olson, 2020/05/26
- Re: Questions about decoding subframe messages (ublox F9P), Gary E. Miller, 2020/05/26
- Re: Questions about decoding subframe messages (ublox F9P), Curtis Olson, 2020/05/26
- Re: Questions about decoding subframe messages (ublox F9P), Gary E. Miller, 2020/05/26
- Re: Questions about decoding subframe messages (ublox F9P), Curtis Olson, 2020/05/26
- Re: Questions about decoding subframe messages (ublox F9P), Gary E. Miller, 2020/05/26
- Re: Questions about decoding subframe messages (ublox F9P), Curtis Olson, 2020/05/26