Re: Running multiple instances of gpsd

[Laurent Smadja]

Hey Gary !

Thx for this quick reply and all recommendations !

Still have some questions.

> Not required.  You can just do this:
>        gpsd -n /dev/ttyACM0 /dev/ttyACM1

My point is to get 2 positions so that I can compute the heading anytime, using the known antenna positions on my robot (with a large enough baseline)

What does gpsd do when connected to 2 receivers ? Does it average the 2 positions ?

How could I retrieve 2 distinct positions ?

> Please note that, for now at least, I don't want to run gpsd using
> systemd.
> Thank you!

Why don't you recommend using gpsd with systemd ?

> 3 things:
> !. Run gpsd as root, not under sudo

ok

> 2. All options go at the front, devices at the end.

ok

> 3. Do not use -p unless you really, really, know what you are doing.

We manually configured our receiver to output a 5Hz position, among other things, and didn't want gpsd to overload these parameters.

> Instead:
$ sudo su -
# gpsd -nND 2 /dev/ttyACM0 /dev/ttyACM1

Noted, thanks, I'll see what kind of output I get.

Thanks again, for this reply, and for gpsd :)

BR

Laurent

On Mon, 6 May 2024 at 20:44, Gary E. Miller <gem@rellim.com> wrote:

Yo Laurent!

On Mon, 6 May 2024 13:57:54 +0200
Laurent Smadja <laurent.smadja@konboi.one> wrote:

> Hi everyone,
>
> I have two ublox f9p receivers in a specific computer:
>  - /dev/ttyACM0
>  - /dev/ttyACM1
> and I'd like to run 2 instances of gpsd, so that I can retrieve gnss
> data from both receivers.

Not required.  You can just do this:
        gpsd -n /dev/ttyACM0 /dev/ttyACM1


> I'm running gpsd 3.22 (rev 3.22), on Ubuntu 22.04.4 LTS (jammy)

Can;t help you with old binaries that are not frim us.

> Since I did not receive my second antenna yet, only one receiver
> (ttyACM0) is connected to an antenna.

Many of us have antenna splitters around to avoid not having
enought of the right antennas arouns.

> Please note that, for now at least, I don't want to run gpsd using
> systemd.

Thank you!

> I checked:
> $ sudo gpsmon /dev/ttyACM0 -> regular gnss frames can be observed
> $ sudo gpsmon /dev/ttyACM1 -> no data received (since no antenna) but
> ok

OTOH, you used sudo and gpsmon.  The 1st is bad security theater the
last is an old, unmaintained, deprecated developer tool.  It does not do
what you think it does.

> I tried to run:
> $ sudo gpsd /dev/ttyACM0 /dev/pps2 -n -N -p

3 things:

!. Run gpsd as root, not under sudo
2. All options go at the front, devices at the end.
3. Do not use -p unless you really, really, know what you are doing.

Instead:

$ sudo su -
# gpsd -nND 2 /dev/ttyACM0 /dev/ttyACM1


> (no wait, no daemonize, passive mode) -> no problem, cpgs confirms
> that I can get a FIX using my first receiver (connected to the
> antenna) $ sudo gpsd /dev/ttyACM1 -n -N -p --port 2948 -F
> /var/run/gpsd_2nd_antenna.sock
> and get the following error:
> gpsd:ERROR: can't bind to local socket /var/run/gpsd_2nd_antenna.sock
> gpsd:ERROR: control socket create failed, netlib error -1

Yup.  Error.  Several errors. Don't do that.

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