Synthetic-Aperture Sonar: Performance Analysis of Beamforming and System Design

摘要

Studies undertaken to assess the feasibility of applying synthetic-aperture techniques to sonar have been based on the theories developed for radar systems. They have been limited primarily to short-range, high-frequency active systems because the ratio of propagation speed to platform speed is much smaller than that encountered with radar. This study places emphasis on the beamforming aspects, the most important part of a synthetic-aperture system. A general approach is followed to develop a computer model to give estimates of beam patterns with active and passive modes of operation for a stationary target. The model allows the investigations of a number of features of the performance, for example the effect of random phase and amplitude fluctuations, of signal coherence time in the passive mode, and of both deterministic and random positional errors of the synthesizing array. In addition, the usefulness of weighting factors to steer and shape the synthesized beam is considered. the results presented give theoretical guidelines for the design of active and passive synthetic-aperture sonar systems. (Author)