Sub-band Coherence in Broadband, Wide-angle Synthetic Aperture Sonar

TitleSub-band Coherence in Broadband, Wide-angle Synthetic Aperture Sonar
Publication TypeConference Proceedings
AuthorsLyons, AP, Brown, DC
Conference Name4th Underwater Acoustics Conference
Conference DatesSep 3 - Sep 8
Conference LocationSkiathos, Greece

The coherence between sub-bands formed by splitting the total range and cross-range bandwidth data provided by broadband, wide-angle synthetic aperture sonar (SAS) systems yields complementary information to that given in traditional intensity images or by the more recent acoustic color analysis. For a random distribution of scatterers, the spectral coherence will be low when sub-bands do not overlap. Cases where the spectral coherence is high are related to scattering from specific structures such as points or facets that violate the random distribution assumption, suggesting possibilities for using coherence in the detection and classification of targets on random seafloor backgrounds. Data used in this study were collected off the Florida coast in the Gulf of Mexico during the SAX04 experiment in 2004 and the TREX experiment in 2013 using a rail-based SAS system operated by the Applied Physics Laboratory of the University of Washington. In this talk we show the utility of sub-band coherence analysis using 2 to 50 kHz data collected on seafloor areas which included both targets and natural clutter. [Work performed under ONR Grants N00014-16-1-2469 and N00014-16-1-2313]