> Re: time-nuts Digest, Vol 108, Issue 28 > Message: 2 > Date: Fri, 05 Jul 2013 09:18:39 -0700 > From: Jim Lux <[email protected]> > To: [email protected] > Subject: Re: [time-nuts] Speaking of Costas loops > Message-ID: <[email protected]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > On 7/5/13 8:44 AM, Bob Stewart wrote: >> Wouldn't a Cs or Rb clock in orbit be slow due to relativistic >> effects? I'm pretty sure there is a relativistic correction to the >> GPS clocks. >> >> Bob - AE6RV >> >> > > I believe that the original WAAS repurposed transponders intended for > other L-band satellite signals (e.g. Sirius/XM/LightSquared). > > As noted earlier in the discussion, the new satellites might have a > specialized payload, which could have a purpose specific coherent > transponder, rather than a linear translator. > > If it is purpose specific and single channel, then making it immune to > the local oscillator is straightforward.
I worked on a proposal for the original WAAS system. The WAAS signal is not a timing signal in the sense that GPS signals from space are timing signals. WAAS instead sends out a stream of correction data that allows one to greatly improve the accuracy and reliability of GPS signals. So, unless things have changed greatly, the geostationary satellite that broadcasts the WAAS signal need not have an atomic clock. Joe Gwinn _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
