Detection and Location of a Target in Layered Media without Prior Knowledge of Medium Parameters*

Abstract

Without prior knowledge of medium parameters, a method is proposed to detect and locate a target in layered media. Experiments were carried out for liquid/liquid and solid/liquid layered media, and the location of a target in them was obtained using three methods combined, i.e., the least-square method, the method of finding minimum dispersal degree of target distribution, and the snapshot time reversal and reverse time migration mixed method. The medium parameters, i.e., the acoustic velocities of upper and lower media as well as the thickness of the upper medium, were inversed simultaneously. The results show that the position of target is consistent with its actual position. Thus, the detection and location of a target in layered media are achieved without prior knowledge of medium parameters, and it overcomes the difficulty that the common time reversal method only detects the target, but cannot locate it.