In August 2005, numerous test events were conducted in Narragansett Bay (under adverse, moderate, and high signal-tonoise ratio (SNR) conditions) to validate shallow-water acoustic-based detection, localization, and ranging algorithms against surface craft and divers. These measurements were completed at the Naval Undersea Warfare Center Division Newport's Broadband Ocean Acoustic Laboratory, which is a shallow-water development facility for evolving acoustic and light-based technologies that are of interest to the U.S. Navy in areas such as Force Defense and Port and Harbor Security. It is shown that relatively common ambient environmental conditions in Narragansett Bay (such as wind speeds greater than 15 knots) create adverse acoustic conditions and generally poor target detection performance. As expected, the acoustic-based algorithms performed well at moderate to high values of SNR.
Port protection can be enhanced with the establishment of a dedicated shallow-water testbed to evaluate new acoustic and light-based technologies. Efforts are underway at the Naval Undersea Warfare Center to create the Gould Island Acoustic Observatory in Narragansett Bay, capable of validating emerging security technologies. The immediate goal is to obtain long-duration, continuous, real-time monitoring of detection performance against various threats (surface craft, AUVs, divers) in a relatively harsh, shallow water environment. Time-variant observables from various technologies will be obtained, typically as wideband time series data, with synopticity of ambient oceanographic data (wind and waves, sound speed, internal waves, tidal mixing, turbulence, optics). This data will be made available, via secure intranet connections, to government, industry, and university researchers. The long term goal is to validate new technologies and appropriate signal processing algorithms, using data collected from a well-characterized shallow water environment.