Sonar doppler spectra analysis

This study deals with the numerical analysis of the sonar doppler return spectra from the ocean surface. It is assumed that signal is backscattered from the small scale roughness superimposed upon the long crest waves of the ocean. Helmholtz integral approach is used for the plane wave case and Kirchhoff\´s approximations are employed. A carrier frequency of 50 kilohertz is used. For each surface roughness and fixed azimuth angle of , variations in the shape and -3 dB bandwidth of the spectra are studied for incident angles of , and It is found that bandwidth parameter varies exponentially with the angle of incident. Also, varies linearly with the roughness parameter . The results are plotted and are believed to provide a useful information to the system designer.