Bob, You mean the Sun, correct?
Regards, John On Oct 20, 2014 4:16 AM, "Bob Camp" <kb...@n1k.org> wrote: > Hi > > Yes, but there’s this large object in the sky that modifies the ionosphere > as it travels in a “about one a day” track. It appears to be coming up just > about now, but I do need more coffee to be sure … > > The combination of the constellation and the ionosphere are what I believe > give you the once a day (rather than once per 12 hours) bump. > > Bob > > > On Oct 20, 2014, at 3:43 AM, Magnus Danielson < > mag...@rubidium.dyndns.org> wrote: > > > > Bob, > > > > Since the satellite orbit the earth with a period of 11 hours and 58 > minutes, it is actually twice a day. > > > > Cheers, > > Magnus > > > > On 10/20/2014 03:50 AM, Bob Camp wrote: > >> Hi > >> > >> The GPS constellation repeats roughly once a day. It is not at all > uncommon to have a “worst case” sattelite geometry for a given antenna > location. If you have one, it will repeat once a day and show up as a bump > in the timing out of your GPS module. If you track long term data, it will > / may / can keep you from getting to the sort of stability you would expect > in the 100,000 second range. It’s one of the main reasons that things like > GPSD-Rb’s lock up with time constants much longer than 100K seconds. Yes > having a Cs or something similar helps a lot looking for this sort of thing. > >> > >> Bob > >> > >>> On Oct 19, 2014, at 9:26 PM, Bob Stewart <b...@evoria.net> wrote: > >>> > >>> Hi Bob Camp, > >>> > >>> > >>> In your response to Chris, you said: "Once you have it “right” you > really need to check it over a month or two to watch for GPS “once a day” > issues. " > >>> > >>> Could I ask you what you meant by these "once a day issues"? Was this > a general comment, or was it about something specific? As you know I'm > working on a GPSDO and am doing a lot of testing, so if there's something > else I should be looking for, please let me know. > >>> > >>> > >>> Bob - AE6RV > >>> > >>> > >>> ________________________________ > >>> _______________________________________________ > >>> 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. > >> > > _______________________________________________ > > 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. > _______________________________________________ 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.