双基地声呐中匹配滤波旁瓣抑制的优化方法

Optimal Sidelobe Reduction of Matched Filter for Bistatic Sonar

对于双基地声呐而言,回波信号经常会被淹没在强直达波信号的脉冲压缩旁瓣干扰中。提出了一种匹配滤波输出的旁瓣抑制方法。该方法的思想是在匹配滤波输出端设计一个FIR滤波器,使得输出的积分旁瓣电平最小,同时保持主峰输出不变。利用二阶锥凸优化算法获得了旁瓣抑制滤波器的最优解。利用数值仿真,比较了旁瓣抑制方法与常规的汉明加窗方法,结果表明,该方法可在保持输出不变的情况下,提高30 d B的旁瓣抑制性能。利用该方法设计的近中心旁瓣抑制滤波器,局部的抑制性能可达-80 d B。

For bistatic sonar,the weak signal of target is often buried by the sidelobes of strong direct blast after pulse compression. A method is proposed in this paper to suppress the sidelobes of matched filter output. The basic idea is to de- sign an FIR filter at the output of matched filter,so that to minimize the ISL （Integrated Sidelobe Level） ,while keeping the mainlobe unchanged. The optimal solution is achieved utilizing the convex optimization method. In numerical simulation ,the performance of the method is compared with conventional matched filter plus Hamming window methods. The performance is improved 30 dB with output gain unchanged simultaneously. The method is also used to design a close - in sidelobe - free fil- ter. The close - in sidelobe level could achieve - 80 dB in the simulation.