Otherwise, it would be the 1850's and we'd be in gunslinger battles. Though cool to some, the toll would be 2-3x the size and 10x more casualties/collateral damage.
Um, what? You do know that the whole gunslinger cowboy myth is just that, a myth, right? Actual shootouts were INCREDIBLY rare, despite lots of people being armed. Funny how that works, it's almost like people are less likely to start violent confrontations when the odds aren't heavily stacked in their favor.
A compass and some accelerometers(or even a view of the sun and an RTC) are a lousy substitute for the accuracy of GPS; but they do provide a sanity check that could keep you going in approximately the right direction, at least enough to hard-land somewhere nominally friendly, if GPS cannot be trusted...
It's almost certain that this drone DOES have an inertial navigation system - the problem is, how do you know when to use it? The way they usually work is that the navigation system computes two solutions: a hybrid GPS/INS solution to use most of the time, and a backup inertial-only solution. The inertial-only solution doesn't get used by the flight computers unless GPS is out entirely or there's some other very obvious problem. If you spoofed a GPS signal with real coordinates and slowly guided it away, how could the nav system see there's something wrong?
One would think that the GPS the military relies on would be encrypted or something, y'know? How difficult is it to spoof military GPS?
Very. The military GPS signals are encrypted with some pretty large keys that are changed every 24 hours IIRC. However, the nav systems will probably fall back to using the civilian GPS if the military signal is unavailable for some reason. My guess is that you could drown out all the real GPS signals with noise, then feed the target some spoofed civilian signals to get it to go where you want.
Norman Borlaug, credited with saving over one BILLION lives through increasing food supplies, was a biologist. Tell me, how many lives has poetry saved?
COMPASS [for the CDC-6000 series] is the sort of assembler one expects from a corporation whose president codes in octal. -- J.N. Gray