NEAR FIELD TRANSIENT ADAPTIVE BEAMFORMING

Existing Navy beamformers deployed in the fleet have been optimized for use in deept water to provide array gain against slowly varying noise fields to improve the detection of low frequency, long duration signals of interest in the acoustic far field. Conventional and adaptive beamformers (CBF and ABF) that have been optimized in this fasion will suffer performance degradations against short duration signals of interest in a noise environment that is rapidly varying like that of littoral waters, especially when the signals are emitted by a target in the near field. This Phase I exploratory effort will investigate the application of specialized frequency domain and time domain dapative beamformers for providing improved array gain for near field, short duration signals. Particular interest will be paid to shallow water noise environment modeling and adaptive beamformer constraint selection to model realistic beamformer operation. The results of this Phase I effort will include a complete design and performance analysis for an effective Transient Adaptive Beamformer (TABF), a realistic shallow water noise model and transient processing operating concept to facilitate integration of the TABF algorithm into the Fleet.