Visidyne has discovered a now approach to determining whether or not an acoustic contact is submerged. Our approach has distinct advantages over previous methods; these add up, ultimately, to a higher degree of automation (at equal or better performance) and therefore a reduction in the cost of passive sonar. Our proposed work depends on the certain features of the amplitude modulation of ocean acoustic signals. It has long been known that such modulation exists -- multipath fluctuation is the usual example but it has not been suspected that it can be useful. Visidyne has discovered the opposite: the modulation contains much useful information. Our methods have been (successfully) demonstrated on SURTASS data using parameters appropriate to surveillance time scales. The ex- tension to tactical time scales, with significantly reduced time- late, requires further innovation, adaptation and development, as proposed here.
Keywords: Classification Acoustic Asw Signature Formation Passive Sonar Single Channel Envar Broad Band
