Hello Dan, I have a LEA-6T running; have a nice external antenna, etc - it's been running for several days - I will check the 1PPS and report if I find anything like what you've discussed.
Regards, John On Fri, Jan 16, 2015 at 4:03 PM, <d...@irtelemetrics.com> wrote: > Hi All, > > I've been playing a Ublox 6T receivers on a synergy SSR-6Tru module. The > unit has been running as part of a GPSDO. In logging the phase between GPS > PPS and OXCO, a few days ago the normally small amplitude short term (10s > to ~500s) phase wander became rather erratic. For the previous several > months the short term wander was around +/- 3nS to 5nS. All of a sudden > this jumped up to about +/- 25nS. > Anyway, the guess was that it was GPS related. So the first step was to > verify GPS was still using the last survey-in points, which it was. The > modules was seeing 14 or 15 good birds at a signal strength of 35 to 50. > For kicks another survey in (48 hour) was started, which just finished up > today. As soon as the survey in completed the phase wander dropped back > down to about +/-3nS. The change was immediate, like a switch was thrown. > The antenna hasn't moved, but the corresponding survey coordinates from > September and January show a phase center position change of about 1.8m. > This seems like a pretty small number, and wouldn't have expected it to > make that big of a difference. At this point I'm not sure what to think. > > Has anyone seen any of the Ulbox 6T modules PPS suddenly get 'noisy'. Is > there anything else I should be looking at? > > Any recommendations on what I should be setting for NAV5 and NAVX5 > settings that could improve things? Elevation angles, or C/N thresholds? > > I'm quite puzzled by this sudden degradation of the system. > > Thanks, > Dan > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.