Estimation of Towed-array heading using reverberation data.

Towed array sonar are extensively used in a variety of naval, marine and seismological applications for its greater detection performance brought by larger array aperture comparing with other arrays like a hull mounted cylinder array. However, tow platforms such as navy boats often maneuver to avoid other vessels or for other tactical reasons. It is also possible for ocean currents and hydrodynamics to affect the heading therefore shape of the array. Under these conditions, heading of the array will differ from that of the boat, which will cause a great performance degradation of target localization. A commonly used technique to solve the problem is to measure the non-acoustic characteristics such as heading, depth, roll of the array directly through non-acoustic sensors embedded in the array. While non-acoustic sensors will add extra cost and don't work well sometimes. In this paper, a method for estimating the heading of the towed array without any extra sensor modules is proposed. When the sonar works in active mode and a pulsed single-frequency signal is transmitted, the angle difference between heading of the array and the boat can be estimated by processing of the reverberation data without using nonacoustic information. This article will give the results of simulation and trial data analysis, which effectively improves the ability of the towed array to detect weak targets and distinguish between left and right side resolution.