Methods for Identifying and Controlling Sonar Clutter

Three methods for identifying, characterizing, and controlling active sonar clutter are described and demonstrated on broadband, low-frequency (<;1800 Hz) normalized data collected in two range-dependent, shallow-water environments: the Malta Plateau off Sicily and the Stanton Banks off Scotland. One method examines short time-scale clutter persistence to stabilize/minimize coherent propagation effects. A second method correlates strong clutter echoes with the depth-weighted topographic slope (relative to the sonar) to help predict the significant scatterers. A third method involves moment-based statistical measures [Poisson-Rayleigh-inspired method (PRIM), K-distribution shape parameter, kurtosis] to distinguish between spatially compact and spatially extended clutter objects. As illustrated with the isolation of several anthropogenic objects from widespread topographic clutter on the Malta Plateau, the new Poisson-Rayleigh (P-R)-based method appears to offer some promise in regards to reducing the false alarm rate.