Multistatic extension of time reversal sonar

In the multi-path sonar application, time reversal methods are noticed to be effective for target detections. The time reversal methods possess an advantage that they dose not require propagation route structure in advance. However, the methods are hard to indicate target distances in the highly noisy or highly reverberant conditions because it is difficult to distinguish signal peaks from noise or reverberations. If the methods estimate target direction, it is able to obtain target position by multiple sonars even in such conditions. Target positions are estimated by detecting a crossing point of target direction lines which are results of multiple sonar time reversal processing and drawn form each sonar. This new concept is presented and problems for practical use are discussed in this paper.