Re: How to avoid 1Hz batching of 10Hz GPS fixes?

[Gary E. Miller]

Yo Chris!

On Wed, 16 Oct 2024 10:46:11 +0100
Chris Dew <chris.dew@thorcom.co.uk> wrote:

> >     what version gpsd,  
> root@C934E761:~# gpsd --version
> gpsd: *3.22* (revision 3.22)

That is almost 4 year old.  A lot of fix and improvements since then

> >     gpsd binary from where,  
> root@C934E761:~# dpkg --list | grep gpsd | head -1
> ii  gpsd 3.22-4+devuan2                     arm64        Global 
> Positioning System - daemon

You need to file a bug with them.  Shame on them for shipping old stuff.

> >     what hardware are you running on  
> iMX8M

That is a family name, not a model number.  What model number?
Quad core?  A a lot of unused CPU?

> >     what command line to start gpsd,  
> 
> root@C934E761:~# ps -ef | grep gpsd | head -1
> gpsd      3332     1  0 08:10 ?        00:00:07 /usr/sbin/gpsd -n -P 
> /run/gpsd.pid */dev/ttymxc1

Should be fine, what is that asterisk doing there?

> >     serial or USB connection,  
> serial

What speed?

> >     how are you measuring "arrival"  
> By eyeball.  Do you know of a time-stamping gpsd client?

Many good ways.  "gpspipe -w -t", or send the gpsd log to a timestamping
syslog.  Or "ubxtool -t".  Try ubstool both with, and without gpsd running.

Or, run gpsd under strace.

> Could you suggest a way that I could see whether the traffic from 
> /dev/ttymxc1 into gpsd is also batched?  This might be a ublox issue, 
> rather than gpsd.

Send the output of "ubxtool -P CONFIG" and "ubxtool -P STATUS"

But, before you do any of that, update to gpsd 3.25 or better yet git head.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
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