Time reversal and time delay focusing for proud and buried target

In order to provide the passive and active array with replica vector for achieving transmitting and receiving focusing on proud and burried targets, the time reversal mirror-virtual source array-refracted spherical wave beamforming (TRM-VSA-RSBF) method is proposed. The original idea is from the work of S.C. Walker et.al. We develop their work in two aspects. First, we generalizes the method to the problem of focusing on target locating either above or beneath the water-sediment interface; Second, from reciprocity principle, such method is generized and applied not only to active focusing but also to passive focusing. That is, to use the replica vector from TRM-VSA-RSBF method to achieve beamforming at the receiving array. Simulation and tank experiments were conducted to verify the validity of the proposed method.