The characteristics of sound propagation in deep water and underwater sound source ranging in the direct zone

The multiple-path sound propagation in deep water is conducive to bottom-based detection and localization of the underwater target.The transmission loss and broadband pulse multiple-path propagation characteristic from a deep receiver are analyzed using the experimental data achieved in the non-full deep water area of the South China Sea.And according to the relationship between the delay and the source range,a ranging estimation method is presented to localize the underwater target.The results indicate that the horizontal width of the direct zone is about 30 km and the transmission loss is less than that in shadow zone when a near-bottom receiver receives the signals from a shallower source,which are beneficial for underwater sound source detection.Moreover,the delay between the direct path and the bottom-surface reflected path on the deep receiver decreases monotonically with the source-reciever range,which can be used to estimate the range of underwater sound source.The underwater sound source range estimation results are consistent with the GPS measurement.And the mean square error of the range estimation results is 0.28 km.