中文摘要：

将时反选择性聚焦方法应用于浅海波导中的信混比增强，提出了一种基于时反选择性聚焦的信混比增强方法。在没有探测声源的条件下，通过对返回的回波信号进行时反算子分解获得时反阵与目标及海底散射体之间的传输函数信息，取一个与目标对应的特征向量作为时反阵的激励权向量，可以实现声场在目标处的选择性聚焦，并抑制相应距离上的海底混响，从而增强回波信混比。该处理方法解决了直接时反处理需要探测声源和混响零点设置方法在海底处设置混响零点的同时也会在目标位置设置零点的问题。利用典型浅海波导环境，进行了计算机仿真实验．验证了该方法的有效性。

英文摘要：

Time reversed selective focusing method based on the decomposition of the time reversal operator is applied to on ratio enhancement in shallow water. In the condition of no probe source, the transmission functions between the source-receiver-array and scatters including target and bottom scatters are extracted by the decomposition of the time reversal operator method from the return signals. And an appropriate excitation-weighting vector of source-receiver array is selected for the shallow water waveguide environment, where the bottom reverberation often dominates the return signal, so as to focus sound energy at the target and enhance the echo-to-reverberation ratio. This method remedies the shortages of the direct time reversal processing which requires a probe source, and the reverberation nulling method which would place null at the target while at the sea bottom. Simulation results indicate the efficiency of the presented method.