Hi Tom: Couldn't find the key to reading that series 7 data, but did find this weekly one: http://maia.usno.navy.mil/ser7/bulb.dat where there are column headings.
I think I'm seeing a 100 ms change in the last 3 months. On your Frequency Stability plot (Max TI error) at 1 day the point is at 4.3E-3. Can you help me understand this Allan plot? For example what can be said about the variation in a one day period measurement? What is the slope and is it of a known noise type? I'd like to see a replot of the Log PSD graph where the X axis is days. That way the peak at 4.133E-7 Hz would be more like 28 days and it would be interesting to see where the others were. Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com Tom Van Baak wrote: >>Setting your clock using GPS time, or with the known offset UTC is straight >>forward. Offsetting UTC using the posted value of DUT1 gets you UTC1 good to >>0.1 seconds. But that's 8 orders of magnitude away from the precision of UTC. > > > Correct. See plots of earth accuracy and stability: > > http://www.leapsecond.com/museum/earth/ > > >>Is there some way to get TT to better than a tenth of a second, or is the >>earth >>just too sloppy of a time keeper? > > > Don't know for sure but the following may help you: > > http://maia.usno.navy.mil/ > http://www.iers.org/MainDisp.csl?pid=36-9 > http://maia.usno.navy.mil/ser7/finals.daily > http://maia.usno.navy.mil/search/search.html > > My recollection is that using VLBI, UT1 is measured to > sub-millisecond even microsecond levels. > > For example, yesterday UT1-UTC was -148.709 ms, today > it is -149.996 ms, and tomorrow it will be -151.172 ms. > > /tvb > > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
