I'm wondering what the best approach for this is. I'm looking for a distance sensor to readout the precise distance within a few inches of a beacon or sensor without line of sight. For example, if I were to give my friend the sensor(in his pocket) in a crowded mall and have him walk away, it would tell me his exact distance from the receiver. The accuracy can be +/- a few inches and the max range can be under 200ft.
Thanks!