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Re: [gpsd-users] Communication loss with GR-701W

From: Gary E. Miller
Subject: Re: [gpsd-users] Communication loss with GR-701W
Date: Sat, 18 May 2019 11:46:02 -0700

Yo Benoît!

On Sat, 18 May 2019 14:14:12 +0200 (CEST)
Benoît Thébaudeau <address@hidden> wrote:

> I'm using a Navisys GR-701W (u-blox 7, USB PL2303 interface) with
> gpsd 3.18, PPS, and ntp 4.2.8p13.

3.18 had a bug, which is why 3.18.1 cam out shortly therafter.

> Most of the time, this setup works fine, but from time to time, after
> hotplugging the GR-701W module, gpsd switches to the UBX protocol,
> then gpsd no longer indicates any received packets, as if the module
> became quiet.

I have a number of GR-601W running.  I've not seen that problem.

When you hotplug the GPS gets reset to stored configuration.  You
should check how you have your GPS configured.  It is easy to 
program the u-blox to ouput no data on startup, that can cause

> The PPS continues to work fine, though (and the LED of
> the module blinks normally). When this happens, right before the
> issue, gpsd reports a warning containing an error, apparently sent by
> the module. I cannot post the exact log right now, but this warning
> looks like this: gpsd:WARN: TXT: trk tick error[...]

The exact error would be nice.  Better yet the full log.

> Restarting gpsd does not help. In this case, gpsd starts directly
> with UBX, and the PPS still works, but that's all.

Have you tried ubxtool to reset the configuration?

> I have a few ideas to debug this using the gpsd debug log, gpsmon, a
> USB sniffer, or ubxtool/u-center, but it won't be easy if it's
> something going on inside the module. Perhaps sending a hot hardware
> reset command to the module could be a good workaround.

Sending different types of reset is easy with ubxtool.

Also, since this happens on hotplug, how is your udevd setup?

> I will post an update when I have more information.

And update to 3.18.1.

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

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