On 5 Jul, 2013, at 08:33 , Bob Camp <li...@rtty.us> wrote: > The sat needs to transmit at the GPS frequencies and have an uplink that > works exclusively with those frequencies. (or at least that sub band). A > "normal" transponder probably would not radiate at the GPS allocation, simply > to be a good citizen. I believe the "specialization" is simply a frequency > mod to allow WAAS to pass through. There is no mention of a space qualified > Cs and / or Rb flying on those birds and no indication that the ground > segment is controlling such a payload. If all that *was* present, then > including them in the normal navigation solutions would be a "zero cost" next > step.
Addressing the last sentence I found a government WAAS reference which indicates that the WAAS satellites are indeed interchangeable with GPS satellites in navigation solutions. It is is on page 7 of this http://www.gps.gov/technical/ps/2008-WAAS-performance-standard.pdf where it says The WAAS GEO broadcast also provides an additional ranging source for improved availability of navigation services. When a WAAS receiver is using the corrections and integrity messages broadcast by the GEO, only four GPS or GEO satellites are needed, which increases the availability of service versus RAIM or RAIM/FDE. While what is or isn't required in the satellite to support this is still a mystery it seems like the timing accuracy coming back must end up being equivalent to a real GPS satellite. What this is good for is interesting to think about. Dennis Ferguson _______________________________________________ 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.