Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!pasteur!ucbvax!tut.cis.ohio-state.edu!unmvax!deimos.cis.ksu.edu!rutgers!att!cbnews!doug@loihi.hig.hawaii.edu From: doug@loihi.hig.hawaii.edu (Doug Myhre) Newsgroups: sci.military Subject: Re: Spoofing GPS signals? Message-ID: <5984@cbnews.ATT.COM> Date: 27 Apr 89 03:10:55 GMT Sender: military@cbnews.ATT.COM Lines: 39 Approved: military@att.att.com From: doug@loihi.hig.hawaii.edu (Doug Myhre) "Clifford Johnson" writes: > Does this mean that giving our nuclear missiles GPS- > based guidance systems makes them vulnerable? Self- > destruct mechanisms were avoided because of the > possibility of Soviets spoofing the signals - what > could they accomplish if they could spoof the GPS > signal, and how feasible is it to do so? The GPS satellites have two different sets of data coming from them. The first is for civilian use. With the correct equipment and satellite availability you can get GPS navigational data for yourself along with the time and other quality data. This might give a position to within 3 meters. I do not believe that there is error detection/correction data sent for the time itself. Even if there was, I would think that this could be falsified. The second set is a encrypted set of signals that is for military use only. The position data available to the military is much more accurate than for civilians. Undoubtedly they don't want the Soviets, or any other unfriendly force having accurate enough data for military uses. Because the military's signals are encrypted, I would think that this would make it hard for anyone to mess with them. I don't have any idea how the data is encrypted. Military used for location probably accurate to within inches would have may uses. Just look at missile guidance. If your nuclear missile knows exactly where it is at all times (not only latitude and longitude, but also altitude), it can hit very accurately. Doug Myhre Hawaii Institute of Geophysics Research Computing Facility 2525 Correa Road Honolulu, HI 96822