US Patent 7187324 Radiowave monitoring method and apparatus

Arrival directions and patterns of intensities of radiowaves are observed by a monitor station 12a. An observed pattern given by the monitor station 12a is compared with simulated patterns of intensities and emitting directions of a simulated radiowave, and a position whose simulated pattern shows the best correlation with the observed pattern given by the monitor station 12a is identified as a location of the radiowave emitting source. Accordingly, a time for preparing data base by the radiowave propagation simulation can be decreased, and the radiowave monitor can be more efficient.