Danny Mayer <[email protected]> wrote: > On 12/28/2011 12:09 AM, [email protected] wrote: >> Danny Mayer <[email protected]> wrote: >>> On 12/27/2011 8:48 PM, [email protected] wrote: >>>> 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. >>>>> >>>>> Danny >>>> >>>> How do you measure distance with an atomic clock? >>>> >>>> >>> >>> That's a complex question. GPS (even the military version) is not >>> accurate enough. >>> >>> Danny >> >> No, it is not complex; you can't measure distance with an atomic clock. >> >> An atomic clock is used to measure time intervals. >> >> As for GPS, it is pretty trivial these days to determine an absolute location >> to parts of a centimeter for a fixed location. >> > > There's no such thing as an absolute location. See Einstein. > > Danny
Absolute within the frame of reference of GPS, which in case you didn't know, is the Earth. See Spot run. -- Jim Pennino Remove .spam.sux to reply. _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
