Hi The whole clock error / orbit error thing can be corrected after the fact with data from various agencies. It impacts survey work at least as much as timing. Looking at it that way, it does not really present a hard limit.
The “what’s the frequency limit?” question depends on just what you mean by frequency. Is it the phase change over a second? ( = a one second counter gate time). In that case you are closer to the ppb range than ppt. Is it 50% of the time, 90% of the time or 99% of the time? Each step you take makes things look a bit worse. There (effectively) is no "100% of the time” answer to the question. ADEV was invented to some degree because this had people very much tied up in knots “back in the day”. Do you average your readings in some way (like to get them on a frequency vs time plot)? That will impact what you “see” as the answer ( = 86,000 data points don’t fit on a normal monitor screen … or printed page). Lots of qualifiers …. Bob > On Jul 10, 2019, at 2:44 AM, Perry Sandeen via time-nuts > <time-nuts@lists.febo.com> wrote: > > Yo Bubba Dudes! > In a number of fascinating and highly educational for me were the explanation > of accuracy by TVB and others. I learned quite a lot, thank you. > Bob mentioned about slight orbital variations in the GPS satellites. > IIRC those slight variations meant that you could only reliably get about > 1x10^12.accuracy. > Would someone please expand on what the practical frequency calibration limit > might be? > Regards, > Perrier > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
