Signal Processing Algorithm and System Realization of Broadband Parametric Array Sub-Bottom Profiler

Abstract

Parametric acoustic array can generate a low frequency narrow sound beam with sufficient penetrating ability with a small size transducer. Besides, the generated beam has almost no side lobe, and it is easy to form a wide band signal at low frequencies, thus effectively improving the signal processing gain. Therefore, broadband parametric array shows advantages in shallow water sub-bottom profiling. In this paper, the signal processing algorithm of transmitting end and receiving end of parametric array sonar was studied, and a parametric array sub-bottom profiler was designed and realized for experimental verification. Based on Berktay’s far-field solution, the performance of different modulation methods was analyzed and compared, and suppressed carrier double-sideband modulation was chosen as the optimal modulation method. Furthermore, corresponding echo signal processing algorithm was designed to improve the detection resolution. According to lake trials of the broadband parametric array sub-bottom profile measurement system as designed, a clear sub-bottom profile was obtained, which verified the system’s effectiveness.