On 2011-12-28, Danny Mayer <[email protected]> wrote: > On 12/24/2011 8:10 PM, [email protected] wrote: >> John Hasler <[email protected]> wrote: >>>> The open sky nearest the OPERA detector is straight up through 1400m of >>>> rock. >>> >>> Jim Pennino writes: >>>> And the easiest open sky to get to is horizontally down the tunnel to >>>> the entrance which is next to a freeway. >>> >>> Yes, the entrance is next to a freeway. The entrance to the LNGS >>> facility where the OPERA detector is located is near the middle of the >>> 10 km long Gran Sasso highway tunnel. >> >> The bottom line is that the only thing that is relevant is how easy it is >> to get to a GPS antenna with an open view of the sky. >> >> Everything else is bloviation. > > GPS is not used for this kind of thing, they are too inaccurate, so it > doesn't matter. They use atomic clocks.
No they do not. They use GPS. As has been discussed here gps can be made accurate to a few ns. GPS is used by radio astronomers to synchronize very long baseline arrays. (Yes, I also thought that gps was not accurate enough. I was wrong) > > Danny _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
