Abstract: An adaptive beamformer and signal processor for sonar and other signal receptor arrays, in which beamforming is accomplished by correlation feedback loops providing matched weighting across the array. To constrain the adaptive beamformer thus comprised against cancellation of useful signals from a particular angular region, which normally is the beam mainlobe or boresight region, one or more spatial notch filters are interposed within the correlation feedback loops for preventing signal suppression within such angular region.

Abstract: The present invention relates to an adaptive signal processor for reducing interference in ranging and communication systems resulting from jamming or multipath reception. More particularly, an optical signal processor is provided in which a first time correlation is performed between the receive signal derived from a direction antenna and an interference signal derived from one or more auxiliary omnidirectional antennas in an acousto-optical device to obtain one or more corresponding weighting functions stored as a function of signal delay. The auxiliary signal is then correlated in a spatial correlation process in which the auxiliary signals are delayed and multiplied with the weights and the result spatially integrated to derive the predicted interference. The predicted interference is then subtracted from the main signal in an adaptive feedback loop wherein the predicted signal is made to approach equality with the interference.

Abstract: The velocity measuring correlation sonar disclosed employs a planar array of receiving transducers spaced in the directions along which velocity components parallel to the plane of the array are to be measured, and includes means for transmitting a series of two or more identical pulses which are separated by a time interval selected in accordance with transducer separation and the estimated velocity components so as to place the expected point of maximum correlation of the echo return from one pulse with that from a following pulse within the boundaries of a set of spatial sample points representing relative spacings between pairs of receiving transducers. Correlation measurements are made corresponding to these relative spacings of the receiving transducers, with each such measurement being treated as a sample of a space-time correlation function of predetermined shape.