Retransmission?
From a purely technical perspective, wouldn't retransmission of GPS signals with a high powered transmitter be able to achieve something like this? Low-powered retransmission of GPS signals is sometimes used to improve GPS coverage indoors, but if done with a high power transmitter that drowns out the signal from the satellites to nearby receivers, wouldn't that make other receivers think they are at the location and altitude of the retransmitted signals..?