There are a couple levels of GPS protocols on a satellite . The one that everyone uses in the USA for things like driving has a very limited accuracy. The ones the military uses are capable of resolution up to 2 inches at the equator and up to 6 inches in areas like Iran. The signal cannot be faked or replicated and then sent to the drone unless they have cracked our encryption. The encryption isn't one where you cannot decode the signal without the key , it is one where when you combine 3 different signals they all have to have a value that is the same as what the controllers on the ground are expecting. It changes constantly so to fake it someone would have to fake all 3 satellite signals in real time .
I don't think the CIA lost this drone. Too many things went wrong like nobody sending the destruct command, I think this was a gift to Iran. It wouldn't surprise me if the software and hardware doesn't contain some very special payloads just for Iran.
I get the impression you are writing primarily about the controllers. I assume these are the command/control centers of the drone. If the drone itself does not receive any more data from the controller, the drone would fly to a preprogrammed save landing zone. The GPS coordinates should have been preprogrammed outside enemy territory, just to be on the save side.
But i would think that the developers of such a plane would have added extra sensors for flight speed, altitude, acceleration, gyroscopes to keep track of roll, pitch and yaw, even magnetic compass and more. Just in the case GPS communication is lost or compromised. Then the drone would just use internal sensors to maintain position or even fly back to a known save location(with room for position error) by backtracking sensor data. Then GPS can be checked again.
By using multiple sensor data in flight and comparing this data with GPS information in real time, it would have been very hard to spoof GPS communication with this drone. The results will be off maybe a hundred miles or kilometers, but that is just a question of making sure that the drone is further away from enemy territory as to compensate for error in position.
Maybe the software/hardware combination of this drone is not advanced or fully developed enough yet for such features, but i seriously doubt that. It asks also for a lot of storage. But this kind of sensor data gathering and comparing is serial in nature thus perfect for current storage technology. Timestamping comparing with speed is the natural index.
It still seems to me as a malfunction, a design flaw,that is only now becoming apparent. These things are known to happen, also in the military.
However, landing the drone on purpose as a trojan horse... Knowing current state of the art technology(not the mainstream cheap consumer tech) It is possible...
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