LFA and CFLA Acoustic Sensors

Advancements in submarine quieting technologies have made the threats faced by the U.S. Navy increasingly difficult to localize using traditional passive acoustic sonar. This difficulty has renewed interest in optimizing the performance of active sonars such the Low Frequency Active (LFA) and Compact Low Frequency Active (CLFA) systems for the Surveillance Towed Array Sensor System. LFA and CLFA were originally designed for use in a deep-water, low-clutter environment. Active clutter has significantly increased as these active systems have moved to littoral areas.Adaptive Methods proposes to develop an active adaptive beamformer (ABF) for LFA and CLFA which provides improved active clutter reduction and improved signal to interferer and noise ratio. ABF algorithms ability to suppress loud acoustic interference arriving in the sidelobe region of beams will reduce clutter and improve detection performance. Adaptive Methods proposes to apply our approach to Robust Adaptive Matched Filtering to beamformed data that will improve the detection of weak signals of interest normally masked by loud interference in correlations. The feasibility of our concepts will be demonstrated by use of at-sea data and comparison to the existing processing system.