Passives Verfahren zum Gewinnen von Zieldaten von einer Schallquelle

A passive method for obtaining target data from a sound source disposed in a nonsolid medium by means of a sound receiver remote from the sound source, by the steps of: providing, as the sound receiver, first and second sound-to-electrical signal transducers constituted and positioned to each respond to a respective one of two sound waves propagated from the sound source to the sound receiver at respectively different propagation speeds; and deriving, by means of an electrical signal processing system connected to receive output signals from the transducers, target data from the sound source by determining the frequencies of, or the difference in reception time between, the sound waves emitted by the source and to which the two transducers respond.