On Wed, Apr 27, 2016 at 7:51 AM, Attila Kinali <att...@kinali.ch> wrote: > > > > Another way would be to use L1/L2 receivers with calibrated antennas. > I know that BIPM has a GPS station that can deliver time transfer > accuracy <2ns over a distance of several 100km. It could be possible > to use such receivers with the <3km distances to deliver 10 times better, > if they are frequently calibrated (eg. every couple of days).
> But of course, this makes things much more expensive. > > But all this is a wild guess. I haven't seen anything like this done. There was a discussion in 2005 that's pertinent to this: https://www.febo.com/pipermail/time-nuts/2005-August/019158.html The references are interesting, with some real data about what is achievable on short baselines. eg Fig 7 in http://gpstime.com/files/PTTI/PTTI_2002_CNS_Testbed.pdf shows that two receivers keep within about 5 ns of each other on a 21.5 km baseline. As I think I said in a similar discussion a few weeks ago, two identical geodetic receivers that I have on a 400 m baseline keep within about 100 ps of each other, using a Precise Point Positioning solution for the (common) clock. If you were brave, then 2 km would scale to 500 ps synchronization (works for 5 ns/20 km too ..) Cheers Michael _______________________________________________ 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.