Sextent, compass, and clock. Amazingly as posted on time nuts some time ago the Navy and Coast Guard have re-introduced that training.
On Mon, Aug 14, 2017 at 1:24 PM, Magnus Danielson < mag...@rubidium.dyndns.org> wrote: > Hi Jim, > > On 08/14/2017 06:03 PM, jimlux wrote: > >> And GPS users who care about spoofing tend to use antenna systems that >> will reject signals coming from the "wrong" direction. It's pretty easy to >> set up 3 antenna separated by 30 cm or so and tell what direction the >> signal from each S/V is coming from. >> >> I would expect that as spoofing/jamming becomes more of a problem (e.g. >> all those Amazon delivery drones operating in a RF dense environment) this >> will become sort of standard practice. >> >> So now your spoofing becomes much more complex, because the sources have >> to appear to come from the right place in the sky. (fleets of UAVs?) >> > > You gain maybe 10 to 20 dB, but not much more. > A real protection scheme needs much more tolerance to handle severe > problems. > > There is an overbeliefe in such approaches, rather than trying to look at > the system analysis, since when you loose the GPS signal, what do you do. I > get blank stares all too often when I ask that trick question. > > Cheers, > Magnus > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ 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.
