On Feb 29, 5:45*am, "Artful" wrote:
"Paul B. Andersen" wrote in ...

So which "initial coarse correction after the clock is launched"
are you talking about, Henri?
If such an individual correction is done, why are then the difference
in clock rates as can be expected by clocks which are _not_ individually
corrected?

To defend Henri for an instant, it is possible he is thinking about the
original satellites, which were launched with the GR correction as remotely
settable. *They were initially launched with the GR correction turned off,
and left to run like that for several days (I don't have the details here to
quote exactly) to see if the correction was actually needed (as some of
those involved doubted the GR correction was real). *After that time, it was
found that the correction WAS needed, and so the synthesized clock
adjustment was turned on.

From Neil Ashby's site:
http://www.leapsecond.com/history/Ashby-Relativity.htm
http://www.leapsecond.com/history/19...I-v9-NTS-2.pdf

Of course, for later satellites, there was no need for such a switch any
more, they could be made with the correction built-in.

Anyway.. that sounds like a possible explanation for what Henri was saying..

Henri is also fond of declaring that there has never been
an experimental test of relativity, and that the GR
correction for GPS is only "roughly" the same as the
actual rate difference "by coincidence". Hence the importance
to his mythology of insisting that there is a fine
rate correction done on station.

- Randy