Analysis of Side-Looking Sonar Performance in the Near Field under Dynamic Conditions

Abstract

A detailed analysis has been performed of a side-looking sonar working in the near field where the platform is permitted to move through three rotation angles and three displacement vectors during the transit time of each sonar pulse. The polar diagram of the side-looking sonar was calculated in the near field on a digital computer for various combinations of the aforementioned dynamics. Detection and target recognition criteria were established using the signal characteristics of the sonar transducer. The detection operation is performed on the shadow function displayed to the operator on a film strip. The complicated nature of the transducer polar diagram was combined with signal-detection theory to obtain a family of detection- and recognition-probability curves as a function of ocean-bottom geometry and the dynamic behavior of the sonar platform. The analysis included consideration of bottom-reverberation characteristics, sea attenuation, thermal-noise target characteristic, and sonar performance parameters.