refclock 28 gone wacky on me

Eric S. Raymond esr at thyrsus.com
Fri Jun 10 07:35:51 UTC 2016


Hal Murray <hmurray at megapathdsl.net>:
> 
> esr at thyrsus.com said:
> > That's odd.  The normal semtence budget including GPGSV should fit inside a
> > second.  Are you getting some kind of $PMTK thing that pushes it over? 
> 
> I'm using gpsmon to watch the output.  There is a pause every second.  That's 
> measuring by eyeball.
> 
> Here is a typical second:
> 
> ------------------------------------- PPS ------------------------------------
> -
> (49) $GPGSA,A,3,25,05,29,21,20,,,,,,,,2.7,1.6,2.2*38
> (70) $GPGSV,3,1,12,20,78,095,26,29,72,090,28,21,51,288,20,04,41,290,20*7F
> (68) $GPGSV,3,2,12,18,36,210,,05,32,047,26,25,28,190,14,26,28,306,07*7B
> (64) $GPGSV,3,3,12,15,24,131,,13,19,093,,16,08,326,,31,00,258,22*7E
> (72) $GPRMC,034045.787,A,3726.0553,N,12212.2633,W,004.3,175.6,100616,,,A*75
> (40) $GPVTG,175.6,T,,M,004.3,N,008.0,K,A*07
> 
> That's running direct.  If I go through gpsd the PPS line has a time but the 
> pause is always there.
> 
> There is a GPGGA listed up high in the Sentences block but I haven't seen one.

OK, the pause is expected.  That's the quiet time after the sentence burst
has been shipped.

What you should see is the PPS bar, followed by a sentence burst, followed
by a pause.  If the burst is wrapping into the next second, it will be instantly
obvious because the burst won't finish (no pause) before the next PPS bar.
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>


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