Element level simulation of sonar echo from a moving target in an ocean waveguide

The source, receiver and target dynamics in an ocean waveguide have significant effects on the performance of high resolution spatial and temporal processing. In a multipath environment, the motion causes Doppler shifts that are different for different paths. A procedure is developed for element level time series simulation for high frequency sonar returns in a monostatic scenario that includes the effects of source, receiver and target dynamics. The extension to the bistatic case is straight forward. The procedure consists of propagating the signal from the source to the target using ray tracing, projecting the incident field on to the scattered field, and propagating back to the receiver. The source, receiver and target dynamics is taken into consideration during propagation from the source to the target and from target to the receiver. The projection of the incident field onto the scattered field is accomplished using a T-matrix formulation. The modeling procedure is applied to a shallow water ocean waveguide with a rigid sphere as a target. The source, receiver and target motion is confined to a constant depth without loss of generality. The results demonstrate different Doppler shifts for different paths and the received signal exhibit the effect of motion