Hi If the WAAS birds are run in a fashion that gives a true GPS payload performance, why not assign them a SN 32 or below and use them?
If the WAAS birds are not in the "right numbers", why bother to set them up and spend the bucks to make them behave like a nav sat? What's the payoff? Bob On Jul 10, 2013, at 7:40 PM, "David I. Emery" <d...@dieconsulting.com> wrote: > On Wed, Jul 10, 2013 at 02:42:19PM -0700, J. Forster wrote: >> David, >> >> While I can easily see how you can do closed loop correctioin for Dopplar >> from the transmission point for a 'bent pipe' repeater, at any other >> location that correction would not be valid, because the paths are not >> parallel. > > Sorry for my poor choice of words. That is precisely what I > meant by "for an observer on the ground it is necessary to correct for > the satellite orbit induced doppler". This is true for ANY observer, > since it would seem certain that the closed loop correction actually is > structured and calculated to cause the satellite to radiate a carrier > (and timing modulation on it) equivalent to what an accurate local GPS > satellite reference clock would generate if one was aboard the hosted > payload rather than on the ground. Anything else would make no sense > as it is not incumbent on users to try to figure out ground relative > timing for some unknown uplink antenna somewhere. And offsetting > radiated uplink time and frequency on the ground to make it right on the > satellite at the output of the bent pipe repeater is very feasible and > more or less a no brainer. > > But if the satellite radiates what a local GPS package would and > transmits ephmerides defining its position and motion it could be > included in a GPS solution and could be used for timing and frequency > purposes the same as any other GPS satellite subject to whatever degree > of relative accuracy the bent pipe clock obtains and the degree to which > the ephemerides in the format transmitted allow an accurate position to > be determined. > > And from what I have read it seems very likely the WAAS birds > meet these criteria.. > > > > -- > Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass > 02493 > "An empty zombie mind with a forlorn barely readable weatherbeaten > 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in > celebration of what could have been, but wasn't and is not to be now either." > > _______________________________________________ > 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. _______________________________________________ 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.
