Effects of Sonar Shape Distortion on Time Delay Estimation Method for Left/Right Discrimination

Twin-line array sonar is an important type of towed sonar, which is usually equipped on naval ship and submarine. Left/right ambiguity is an inherent defect of traditional towed sonar, and time delay estimation is the basic method for twin-line array sonar to resolve this problem. While in ocean environment, the line array is often deformed by some physical or mechanical factors. A typical distortion was discussed in this paper where the two lines are mismatched because of mechanical problem. How the shape distortion affects the time delay estimation method was investigated. A critical angle was derived under the condition of shape distortion. Theoretical and simulation results indicated when the incidence of a target exceeding the critical angle, result in the invalidation of time delay estimation method on some bearings. So the shape distortion should be given more attention in physical application of towed array sonar.