Matched-beam processing: Application to a horizontal line array in shallow water

Matched-beam processing of a horizontal line array in a multipath shallow-water environment is presented. With conventional beamforming, the signal is split into several beams when the target is away from the broadside direction. This can result in signal gain degradation and severe bearing bias. Matched-beam processing is matched-field processing applied in the beam domain. It offers an efficient and robust approach for correcting bearing errors and signal gain degradation of horizontal line arrays in shallow water. It is based on conventional beams but extends conventional processing to incorporate full-field processing. It is applicable to existing systems where the conventional beam outputs are the only data readily available. Many of the signal processing algorithms for horizontal arrays, such as adaptive beamforming for nulling strong interferences, can be incorporated directly into matched-beam processing. Target bearing tracking and depth discrimination are illustrated using matched-beam processing for a horizontal line array.