I seem to recall that NASA used optical inferiometry at LC39 for time transfer during the shuttle program for the DSN the inferiometry was used to normalize the delays in the fiber distribution system caused by temperature and gravity
> On May 5, 2016, at 2:44 PM, Tom Van Baak <[email protected]> wrote: > > Hi Mark, > >> Interesting... what happened on day 4 to send them all bonkers? > > What you see as bonkers starting the 5th day is actually normal behavior for > a cesium clock (or any clock, for that matter). I mention this plot because > it shows that you cannot get 500 ps over a day, even with a 5071A -- which is > why we're all trying to help the OP with alternative methods of time > synchronization. > > There are several ways to plot phase data. What people often do is plot > residuals for the entire data set. That is, showing how good the clock would > have kept time *if you knew ahead of time what the rate would be*. The first > 5 days of the plot shows the residuals based on 5 days of rate fitting. At > that point the calculated rate was fixed and the clocks continued to tick. So > it becomes a 10-day plot of phase residuals based on 5 days of fitting. I > like this because it more dramatically shows how hard it is to keep accurate > time. > > The spread in phase is expected. In fact this spread is what ADEV measures; > variations in frequency accumulate to phase drift. Or vice versa: erratic > drift in phase is evidence of frequency instability, which in turn is > summarized with ADEV statistics. I know I'm not explaining this well enough, > and it's a bit off-topic for this thread, but I'll write it up later and post > it. > > /tvb > > > ----- Original Message ----- > From: "Mark Sims" <[email protected]> > To: <[email protected]> > Sent: Wednesday, May 04, 2016 4:41 PM > Subject: [time-nuts] Fw: Optical transfer of time and frequency > > >>> See www.leapsecond.com/tmp/5071a-12-run8-5d-10d.gif for a plot of a bunch >>> of 5071A Cs clocks. >> Interesting... what happened on day 4 to send them all bonkers? > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
