Physics-based Modeling of Acoustic Reverberation in the Littoral Environment

Underwater acoustic modeling plays an essential role in the design, development, test, and operation of sonar systems. Active acoustic clutter can increase the sonar false alert rate or equivalently decrease the probability of detection/classification, and is a key issue in the development and utility of active sonar systems. The ability to predict reverberation and clutter is inseparably tied to other modeling tasks, including propagation modeling as well as boundary and volume characterization. The system sonar equation method supports development of a virtual acoustic environment and can be used to produce time series data for examination of the reverberation and clutter influence in the sonar system’s operating parameters. A multi-tiered approach will be used, including: 1) physics-based clutter research (bottom clutter and volume clutter; 2) development of algorithms to generate stochastic realizations of bathymetry and volume scattering features; 3) development of a semi-deterministic reverberation model; 4) development of a module to incorporate stochastic clutter into a deterministic reverberation output; and 5) development of a Parabolic-Equation/Normal-Mode module. The overall objective is to develop and incorporate physics-based reverberation and clutter modeling approaches into current system sonar equation and propagation models used by the sonar designer, planner, and operator.