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Re: ✘gpsd release coming

From: Fred Wright
Subject: Re: ✘gpsd release coming
Date: Mon, 3 Aug 2020 14:14:27 -0700 (PDT)
User-agent: Alpine 2.23 (OSX 453 2020-06-18)

On Fri, 31 Jul 2020, Greg Troxel wrote:

I have just tested livetested gpsd on NetBSD 8 amd64 as of the following

 commit d3800a04000c9e94f93262505083743b3280548a (HEAD -> master, 
origin/master, origin/HEAD)
 Author: Greg Troxel <>
 Date:   Fri Jul 31 08:53:43 2020 -0400

via making a tarball with scons dist, using that to build a binary
package with pkgsrc, installing that package, running the resulting gpsd
with a ublox 8, verified that it gets position, shows satellite location
and status with xgps, and passes (non-PPS) time to ntpd.  I also checked
ubxtool querying things.

You must not have looked very closely at the xgps output if you think it's OK. You should see several pulsating values in the data box due to its seeing mixed NMEA/binary in "binary" mode.

And if you have any multi-GNSS configuration other than GPS+GLONASS, you should see at least one entire constellation coming and going in both the list and the satview, as well as in the seen/used counts in the data box. This can be seen even with a GPS-only antenna, if you configure it for GPS+Galileo. With a multi-system antenna, configuring for GPS+BeiDou+Galileo shows the largest effect. Though there seems to be some interaction with other timing that makes the exact behavior variable. It also appears that the special hack for GPS+GLONASS has some lingering effect, so restarting gpsd after turning off GLONASS makes it more representative.

Similar behavior can be seen in cgps, and gpsmon is crazier.

Since all of these issues relate to NMEA and UBX "fighting each other", they may be less significant at higher baud rates. But they're definitely visible at 9600 (the default for both gpsd and u-blox 8), and at 19200.

I already reported this a while back in the "NEO-M8N NMEA" thread. I have a series of commits that fix it, but I need to do more testing. It is, notably, a regression since 3.20.

The other oddity is that, even with the other issues fixed, the gpsmon fix pane doesn't work now with a u-blox 8 and did in 3.20. I thought I understood the reason (lack of support for NAV-PVT), until I noticed that NAV-PVT was already being used on u-blox 8 in 3.20, so that aspect hasn't changed. Hence, the real mystery is why it *wasn't* broken in 3.20. Another thing to investigate.

Unrelated to all that, with Python 2, the current code to find libgpsdpacket fails on almost all platforms (including Linux).

Fred Wright

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