Research on the Range-Frequency Interference Characteristics of Target Scattering Field in a Shallow Water Waveguide

Based on the target scattering model and the normal mode theory in a shallow water waveguide, a mathematical model of the acoustic intensity under the coupling condition of the target and the environment was deduced, and the interference striations in the monostatic and bistatic configuration were obtained by simulations. Further, a field experiment was carried out in a lake, and the data were collected for a spherical target in two frequency bands, i.e., 20−40 kHz and 40−80 kHz. The experiment results showed good agreement with the simulations. The results of the simulation and the experiment showed that the existence of the target made the interference phenomenon in shallow water waveguides more complex, and the range-frequency interference characteristics were closely related to the configuration of the sonar system, the target scattering function, the frequency range, and the target movement trajectory. These interference phenomena were found and theoretically analyzed in the paper. The research results can be applied to target detection and recognition, signal parameter estimation, target tracking, and other fields.