[gpsd-dev] refclock 28 gone wacky on me

Gary E. Miller gem at rellim.com
Sun Jun 19 23:06:06 UTC 2016

Yo Mike!

On Sun, 19 Jun 2016 18:45:45 -0400
Mike <bellyacres at gmail.com> wrote:

> > Which is why I asked what your other chimers say.  

> + ( .GPS.            1 u   61   64  377   39.468 6.354 2.236 
> +fairy.mattnordh      2 u   37   64  377   60.559 3.875 0.986 
> -origin.towfowi.     2 u   26   64  377   77.933 1.970   2.503

You are without all of those to better than 6 milliSec.  If you have the
wrong edge you would be off 20 milliSec or more.  So that is reall good.

> >>   I wasn't real pleased and figured I'd have to reset the
> >> setting to get the NMEA delivery back to top of second.  Left is
> >> alone for several hours, come back and gpsmon shows that I was back
> >> to getting delivery close to the top of second again.  
> > Yes, that is expected.  You need to tetll the Skytrazzq to force the
> > top of the second, and save to flash.  
> Did that which is why I didn't understand the delivery coming at near 
> the end of the second.  It appears thought that the firmware *slowly* 
> brings the delivery back to where it should be.

And only one cycle of NMEA per second?  If it takes time to get back to
the top of the second I would report that to Skytraq as a bug.

> >> At that point PPS looks good, NMEA is way out, where before I had
> >> powered the module down is was looking pretty good.  
> > I'm not sure what you mean by 'way out'.  
> Saying the NMEA offset was within at least a few milli seconds.  Now
> I'm nearly .5 second off.

Odd.  The NMEA offset will not stay closer than +/- 100 milliSec over
time.  But 500 milliSec is too much.  Even if the NMEA wanders around in
the second, the offset of the fix from the time of fix should be

Try setting the serial speed to 38400 and see if it persists.

> Okay, ntpshmmon: version 3.17~dev (revision release-3.16-359-g88190a1)

That looks good to me.  The NMEA delay and offset not bad.  Look good to you?

> This just confuses me more...

Looks very good to me.  What looks off to you?

NTP1 is offset under 1 millSec, NTP0 offset about 150 milliSec.  Fine

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at rellim.com  Tel:+1 541 382 8588
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