US Patent 7817092 Agile electromagnetic geolocation

The unknown location of an electromagnetic transmitter is determined by receiving the radiation at plural sensors distributed over an area. Received power is determined at each sensor, and normalized by taking ratios of powers from the various sensors. A plurality of transmitter locations are hypothesized, and losses from each hypothesized location to each sensor are estimated or measured. The losses are normalized. The differences between the normalized powers and normalized losses are integrated, and the mean-square values determined. The location at which the mean-square value is minimum is deemed to be the location of the transmitter.