Jason I couldn't find your post on the prefer - it sounds exactly what I am finding. Incidently the mnea patch does listen to the nmea data (so you could have a totally free standing ntp system. Unfortunately simple GPS receivers don't have the capability you mention, hence the need for sanity checks.
Paul On Wed, 2007-06-13 at 14:25 -0500, Jason Rabel wrote: > Paul, > > What GPS are you using? What OS? What does your ntpq -p data look like? > > If you get a receiver with TRAIM, then you can have it disable the PPS > output when it detects itself getting out of sync, either by bad data or no > lock. Otherwise most GPSes will just keep pulsing away none-the-wiser > (except for their NMEA data which NTP doesn't check against). > > You *could* write extra code in the driver to check various NMEA sentences > (which why it hasn't been done I'm not sure) to make sure it has a proper > lock. > > Or as someone else mentioned, ensure that your antenna has a proper view of > the sky so you do not loose lock. > > I wrote a post just a day or two ago about the PREFER source and how if you > have several internet sources they can out weigh your local (more accurate) > source and thus discard it if you do not have the PREFER flag set. So it can > be a potential issue. > > Jason > > >I am using a GPS nmea/pps source (lets not go into the heart-ache > >involved in getting that working), and a very recent download of ntp > >source, with the nmea patch. Obviously I have a few internet sources as > >well, but use the prefer keyword for the pps source. Obviously when it > >is working the pps is about as accurate as I can get. However when I run > >ntpq -p it isn't quite doing as I want. > >I want to lock exactly to that pps source WHILE IT IS SENSIBLE, and to > >drop back to the internet when it has lost satellites. However ntp > >appears to be taking an average, loaded towards the GPS source. When the > >GPS looses satellites and goes beserk ntp sensibly drops it as a source. > >Your suggestions would be welcomed. > > > >Paul > > _______________________________________________ > questions mailing list > [email protected] > https://lists.ntp.isc.org/mailman/listinfo/questions > _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
