Re: ublox F9P - rover: no RTK fix with default gpsd ublox initialisation

[Gary E. Miller]

Yo Michael!

On Mon, 10 Oct 2022 14:24:00 +0200
Michael Haberler <haberlerm@gmail.com> wrote:

> for my use case I'd want an RTK fix as well as track information -
> both together do not work for me (is there any reason why it should
> not?)

I have made it work, many times, so lte's dive in.

> without the gpsd "--passive" option, I only get an 3D DGPS fix but
> get track info 
> 
> if I run gpsd with "--passive" I go get an RTK fix but no track info
> in cgps -s :

The --passive leaves the receiver in whatever config it was in, so without
telling us that, no way to know what is going on...

> if I force a NAV-PVT message with 'ubxtool -z
> CFG-MSGOUT-UBX_NAV_PVT_USB,1', I get two TPV messages in a row 

Yeah, but that's not a problem.


> the
> above message and this one - note confusingly fix is 3D DGPS, despite
> the above message just sent:

gpsd asses on what the u-blox gives it.  Depending on what messages
you have configured (you did not say), some only report 3D, and some
will report RTK, thuse the toggloing of the gpsd output.  Garbage in,
garbage out.

> how should I go about this? 

Carefully.

> just take track from the second TPV, or take position from first TPV
> and calculate track manually?

Or take whaht you need, when you get it.

> setup: 

You shoulda led with this, incomplete as it is.

> - F9P with RTCM3 fed to UART1 via str2str
> (https://github.com/rtklibexplorer/RTKLIB/tree/demo5/app/consapp/str2str)

How is that F9P configured?

> - UART1 set to 115200 ubxtool -z CFG-UART1-BAUDRATE,115200
> - rtcm feed:  /usr/local/bin/str2str -in
> ntrip://XXXXX:YYYYY@euref-ip.net:2101/GRAZ00AUT0 -out
> serial://rtcm:115200:8:n:1

I can't help you with str2str, I never use it.  WHy are you not using the
built-in gpsd ntrip client?

> - gpsd connected to USB port of F9P
> - gpsd 3.24 build from source 0dbc9e

Good enough.  But if you want to try patches you'll need gpsd from git.

> - RTK fix if run with GPSD_OPTIONS="--passive --speed 460800 --debug
> 1 --listenany --nowait"

Uh?  gpsd has no GPSD_OPTIONS?  Are you using systemd(umb)?

I can't help you with system(umber).

And, as I said above, passive leaves it in whatever config it was in,
so you basically get random config that way.

> - 3D DGPS fix only if GPSD_OPTIONS="--speed 460800 --debug 1
> --listenany --nowait"
> - UBXOPTS=-P 27.31

Not useful without your ubxtool command line....

> happy to provide any ublox config - not sure how what to retrieve and
> how

A good start is to send us the output of gpsdebudinfo.

Then to get the F9P config, do, as root (not under sudo):
        ubxtool -p CONFIG > config.log

And then a sample of your F9P output:
        gpspipe -R -x 10 > raw.log

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

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