SBIR-STTR Award

In the operation of passive sonar systems, some Contacts Of Interest (COIs) radiate detectable amounts of broad band energy; on the other hand, their narrow band components are too weak for initial detection, yet are required for classification. Our new approach to such systems is based on envelope coherence, and offers the following advantages: (1) Its broad band detection threshold is 6 dB better than the conventional detector in typical cases; (2) It supplies the times at which the contact transitions between channels, more accurately than previous methods; (3) It automatically associates the broad band and narrow band features of the COI signature.

Keywords:
Acoustic ASW Passive Sonar ENVAR Detection Classification Signature Formation

The sound at an acoustic sensor in the ocean is amplitude modulated by various mechanisms that include the motion of the source, the time- and space-variability of the propagation medium, and the character of the receiver. We have discovered that the resultant modulation waveform, while complex, nevertheless contains information that is useful to passive sonar, and that can be exploited by suitably designed data analysis (signal processing) algorithms. We have shown in Phase I that these concepts have potential value to the ADS system, in the areas of brad band signal detection, signature formation and classification. The Phase II work will iteratively optimize the algorithms for ADS by exercising them on GFI data sets, measure their performance, and assess their system impact.

Keywords:
SonarADSData AnalysisSignature FormationENVARSignal ProcessingDetection