GPS is complex and I may be wrong. But for rebroadcast to work the transceiver would need to be placed exactly between the user and the satellite in space; mea

GPS is complex and I may be wrong. But for rebroadcast to work the transceiver would need to be placed exactly between the user and the satellite in space; meaning a different location every time the user moves. If not perfectly placed; the radio signal will have travelled further than expected and give the wrong position. I suppose you could attempt to locally recreate GPS signals with multiple transmitters; but this would play havoc with GPS reception outside the building. Why not just use WIFI? Differential GPS is not about rebroadcasting the actual GPS position, but the error from a known position. This allows the device to enumerate the error caused by atmospheric effects.