A Way of Shadow Zone Autonomous Localization of Deep Sea by a Single Hydrophone

The sound intensity periodic structure in the shadow zone is mainly caused by the interference among the bottom-reflected wave, the bottom-surface-reflected wave, the surface-bottom-reflected wave, and the surface-bottom-surface-reflected wave and the corresponding interference period is related to the location of sound source. The traditional method extracts the interference period manually and matches the interference period with the simulation result to estimate the source localization. Manual extraction process is cumbersome and may introduce large errors. In this paper, the mechanism of interference fringe formation is analyzed in depth, and it is pointed out that the interference period is determined by the multipath delay difference, and the multipath delay difference is related to the source localization, so that source localization can be performed. Finally, a method of autonomous extraction of interference period and source location estimation is proposed, and the feasibility of this method is verified by simulation.