On 2/19/07, Poul-Henning Kamp <[EMAIL PROTECTED]> wrote: > >Does it > >rely on the different Doppler-shifts making them distinguishable? > > It would have to, if they were not on different frequencies, they > would sum to a single sinewave and you couldn't tell them apart > (unless you have a direction sensitive antenna).
I don't wish to offend, but that is totally wrong. Even if every satellite were on the exact same frequency, with the exact same doppler, and the exact same direction, you would still have no problem separating the carriers of the multiple satellites. The reason is that the satellites do not transmit carrier. Here is how: Everybody here understands how the PN codes are tracked by despreading. The despreading operation is multiplication, and when you multiply the PN code by the original signal you get a carrier, only from that one satellite. Despread with a different PN code, and you get a different carrier. Thus, while the frequencies may all be the same, they are in separate signals, one out of each correlator. Matt _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
