Could it simply be a spoofing device that spins? Say it broadcasts spoofed GPS location signals that travel along the circle say on 15* and the rest is jamming.

Could it simply be a spoofing device that spins? Say it broadcasts spoofed GPS location signals that travel along the circle say on 15* and the rest is jamming. Then different receivers would think they were in different locations as long as they were both not on the straight line to the antenna. It would also simulate the ship receiver believing it was traveling at seven knots when stationary.