Synthetic aperture sonar: An analysis of beamforming and system design

A model to improve predictions of synthetic aperture processing performance as applied to active sonar is described. Models to date have been based on the theories developed for radar systems and have been limited primarily to the study of short range, high-frequency active systems. The present study follows a general approach to develop a computer model to give the beam output of a multi-ping synthetic aperture sonar from a fixed scatterer. The model allows weighting factors to be incorporated to shape and steer the synthesized beam and allows such system parameters as frequency, pulse length and total integration time to be varied to optimize performance. Results show the degradation due to the deviation of the synthesizing array from a linear course and to a low input signal-to-noise-ratio. It is concluded that a high angular resolution can be obtained at low frequencies and at ranges longer than those considered in previous studies.