Signal subspace projection methods of adaptive sensor array processing

Reduced-rank subspace projection methods are used indirectly in frequency and angle-of-arrival estimation algorithms such as MUSIC and its relatives, but they are not commonly used directly in least-squares detection applications. The author has been exploring their use for the processing of underwater acoustic receiver array data for detection and matched-field localization. He describes and illustrates several techniques that have been developed and applied to signals recorded from different types of arrays