> That's actually quite difficult. Consider that for GPS, each receiver is > seeing a different set of signals (in terms of relative time/phase) from SVs > that are moving. The code phase and doppler have to be consistent, etc. > > I spent some time over the last few weeks thinking about how hard it would > be to build a cheap GPS simulator with an FPGA for testing a single radio. > Generating the NAV messages and the spread codes is easy. Sliding them > around and keeping range, range rate, and Doppler consistent, not so easy. > (some sort of funky chain of NCOs was what I came up with, but I don't know > if that would work)
(1) You are not going to jam the entire Earth. If the receiver is reasonably close by both you and the receiver to be jammed are seeing the same sats. (2) I doubt the company that built the Navy's GPS jammer was constrained by the same budget you were. I imagine they had on order $100M to spend on the project (3) the simplest way to "jam" the signal is to turn the un-encrypted signal off or to re-enable SA. They have the ability to do that selectively over just parts of an orbit but that effects a huge area ===== Chris Albertson Redondo Beach, California _______________________________________________ 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.
