一种自适应的主动声呐直达波干扰抑制算法

为了克服主动声呐编队作战条件下的直达波干扰，达到检测微弱目标回波信号的目的．提出了一种基于频域分块自适应滤波算法的直达波抑制方法。这种方法将自适应滤波理论和匹配相关技术相结合，首先对接收数据做频域分块自适应滤波，再利用已知发射信号副本进行匹配相关，最后提取目标回波信号。其中，频域分块自适应滤波算法相比基本最小均方算法，计算复杂度降低，收敛速度快，基本保证了主动声呐每个探测周期内的直达波抑制和目标回波的提取。通过数值仿真实验表明：在强直达波干扰存在条件下，该算法对目标回波的提取在精度和鲁棒性等方面均优于以往的直接匹配相关方法。

An adaptive algorithm of direct path interference suppression for active sonar detection

In order to eliminate direct path interference （DPI） between active sonars in navy battle formation and to detect weak echoes from underwater targets, an adaptive algorithm based on frequency-domain adaptive filtering （FDAF） to depress DPI is proposed in this paper. The algorithm combines adaptive filtering and replica correlator （or matched filter processing） technology. First, the novel frequency-domain adaptive filtering to the data that come from the receiver array is applied. Secondly, the output of adaptive filtering is correlated with a replica of the transmitted pulse. Finally, the target echo is extracted and DPI is eliminated. Compared with basic LMS algorithm, the new FDAF algorithm with variable step-size factor leads to a considerable reduction in computational complexity, and improves the convergence rate and basically ensures the DPI suppression and the extraction of target echo during a ping of an active sonar transmissio~t Numerical experiments prove that the proposed algorithm is superior to the conventional method in the presence of strong DPI, especially in some aspects such as accuracy and robustness of target echo extraction.