Acoustic communication and modeling in shallow water constrained environments

Sound behavior in shallow water constrained environments such as ports, harbors, and estuaries renders unique challenges and acoustic observations. Improving sound models in these underwater environments offers many advantages, for instance an increased effectiveness in model-based design of underwater acoustic systems enabling harbor security. Our ongoing efforts focus on acoustically characterizing these complicated channels, analyzing acoustic communication system performance, and refining a 3-D beam tracing propagation model for various shallow water sites. This talk will highlight field observations from a bistatic experiment conducted in an industrialized tidal estuary that provided transmission paths in very shallow (<3 m) to deep (approximately 15 m) water depths up to 1500 m in range. Signals transmitted, which included acoustic communication data packets, along various transmission paths and ranges at 8–34 kHz resulted in considerable data for assessing and explaining transmission performance variability. The observations from across the site are compared with simulations from the model to identify feature and boundary reflection properties that contribute or dominate echo structure. A verified comprehensive modeling ability for these dynamic, and acoustically distinct, constrained environments is ideal for executing successful underwater operations in the context of acoustic modem throughput and optimization of other systems. [Work supported by ONR.]