Linear time-invariant space-variant filters and the WKB approximation

Computer simulated output electrical signals, based on derived mathematical models, were generated at each element in a receive planar array of complex weighted point sources. The output electrical signals depend on the frequency spectrum of the transmitted electrical signal, the far-field beam patterns of the transmit and receive planar arrays, and the time-invariant, space-variant, random transfer function of the ocean volume which was derived using the WKB approximation. The computer simulated output signals were processed by a three-dimensional FFT beamformer in order to study pulse propagation in a random medium with applications to underwater acoustic communication, target detection, and target localization. Preliminary results are reported in this paper.