Re: [gpsd-dev] PPS glitch - Venus chip

[Gary E. Miller]

Yo Hal!

On Sat, 30 Jan 2016 17:12:29 -0800
Hal Murray <address@hidden> wrote:

> Here is a graph:
>   http://users.megapathdsl.net/~hmurray/gpsd/SparkFun-PPS.png
> 
> My guess is that the number of visible satellites changes and that
> tweaks the length of the GPGSV sentences to push something over the
> edge.

Ye, that can happen eassily at a low serial port speed.  Have you checked
your serial port speed?  AFAIK, there is no such thing as a USB native GPS,
so there is a serial/usb converter in there.

> If you run out of ideas, I'll write a stand alone hack that will log
> both NMEA and PPS.

No need for more code.  Run the -D up high and filter out the
non-relevant ports, sending output to a file.  Sending it to the console
adds too much delay.

Something like:
        gpsd -nND 7 /dev/ttyUSB0 |& egrep 'PPS|NTP' > out.log.



> > The TOFF is for the serial time, so only for course time. But
> > clearly a bug as only one TOFF should be output per second.
> > Historically that code gets changes by people that do not
> > understand it...  
> 
> Eric:  This is a good example of why I get nervous when you say you
> want gpsd to take over all the ntpd refclocks.  Timing is a second
> class citizen for gpsd.  All that good work you put into collecting
> log files and replaying them ignores time.

I take the flip side to your argument.  Finally Eirc is getting his
hands wet in the dirty pool of time.  I'm looking forward to the
new ntp regression tools getting ported to gpsd so we can finally
run time regressions.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

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