Strauss, Karl F wrote: > I've been tasked (or was it I was volunteered?) to do some basic design & > definition work on an ultra-stable master frequency system for a proposed > instrument that is currently planned to be in an Earth-trailing orbit. > Given the first order accuracy requirement of 1 part in 1E-10, my first > thought was to grab the GPS timing signal. > > Sorry for the newbie questions here: a) Do all satellites in the > constellation broadcast a signal into space (as opposed to, say, bouncing > off some ionospheric boundary layer); and b) is there some website/technical > paper describing expected signal strength for these space-radiated signals? > > Again, apologies to all for the Newbie Q's. Hopefully this will be a fun > topic of discussion > > Thanks > > Karl > Karl
The GPS SVs are well above the ionosphere. However they use circularly polarised directional antennas that point at the Earth. Signal strength in orbits closer to the Earth than the GPS SVs will be comparable with that on the surface of the Earth. When the orbit id further out than those of the GPS SVs the signal strength will be somewhat lower than expected from the inverse square law, as the orbit will only be illuminated by weak sidelobes from favourably positioned GPS SVs. Bruce _______________________________________________ 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.
