Method for the correlation coefficient estimation of the bottom echo signal in the shallow water application using interferometric echo sounder

The article presents a new method for the assessment of bottom echo correlation coefficient in the presence of multiple echoes. Bottom correlation coefficient is a parameter that characterizes spatial properties of echo signal. Large variability of the bottom shape or properties (for example caused by the presence of bottom objects) and the presence of the acoustic shadow strongly influence the value of the correlation coefficient. There is a problem, however, in the proper determination of correlation coefficient of the bottom echo when more than one echo is present. In the shallow water application, the echoes coming to the hydroacoustic array from various directions influence the measured value of the correlation coefficient. The method proposed by the authors challenges this issue by applying a subarray processing based on the initial depth estimation. The article presents the preliminary research results and describes the limitations of the proposed method.