[ntp:questions] xGPS_NMEA / xPPS

Alby VA albyva at empire.org
Fri Feb 24 12:53:30 UTC 2012


On Feb 24, 6:28 am, TomK <foren... at milwpc.com> wrote:
>   GPS PPS is not really flawless. It's reasonably dependable. If you can
> repeat the error, it's almost always software. It looks like the GPS
> lost a fix on at least 3 satellites, so PPS didn't sync. NTP noticed,
> and switched to 'NMEA sentence' time only. Check on satellite fix when
> that happens.
>
> On 02/24/12 05:45, Alby VA wrote:
>
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> >   I've watched as my NTP session has gone between normal and falsetick.
> > Anybody want to toss out an idea of why this is happening and the
> > solution to make it stop?
>
> >       remote           refid      st t when poll reach   delay
> > offset  jitter
> > ==============================================================================
> > -ntp.alaska.edu  .GPS.            1 u   69  128    7  127.532
> > 0.581  19.471
> > +utcnist2.colora .ACTS.           1 u   69  128    7   61.424
> > 15.184  16.376
> > *time-a.nist.gov .ACTS.           1 u   70  128    7   16.060
> > 26.839  25.833
> > +tick.usask.ca   .GPS.            1 u   75  128    7  106.332
> > 20.798  24.112
> > -cronos.cenam.mx .GPS.            1 u   68  128    7   81.165
> > 1.985  11.542
> > xPPS(0)          .PPS.            0 l   13   16  377    0.000
> > 28.105   3.330
> > xGPS_NMEA(0)     .GPSb.           0 l   12   16  377    0.000
> > -11.920   5.476
>
> >       remote           refid      st t when poll reach   delay
> > offset  jitter
> > ==============================================================================
> > +ntp.alaska.edu  .GPS.            1 u   75  128    7  127.532
> > 0.581  19.471
> > -utcnist2.colora .ACTS.           1 u   75  128    7   61.424
> > 15.184  16.376
> > -time-a.nist.gov .ACTS.           1 u   76  128    7   16.060
> > 26.839  25.833
> > -tick.usask.ca   .GPS.            1 u   81  128    7  106.332
> > 20.798  24.112
> > +cronos.cenam.mx .GPS.            1 u   74  128    7   81.165
> > 1.985  11.542
> > oPPS(0)          .PPS.            0 l    3   16  377    0.000
> > 28.630   3.022
> > *GPS_NMEA(0)     .GPSb.           0 l    2   16  377    0.000
> > -25.386  12.305
>
> > ** Ignore the low reach. I just restarted ntpd.
>
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> > questi... at lists.ntp.org
> >http://lists.ntp.org/listinfo/questions





Thanks...  Next time it happens, I'll check to see if its seeing any
satellites..  Thanks, I didn't think to check that.




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