混响背景下回波信号起始位置提取*

摘要

对回波信号起始位置的提取是水下目标检测和识别的关键因素之一。在实际工作中，主动声纳接收到的信号既包含真正的目标回波信号，也包含大量的海洋噪声和混响，而回波信号往往淹没在背景噪声中，因此难以准确提取回波信号的起始位置。论文将分数阶傅里叶变换引入到回波信号检测中，利用滑动窗对回波信号进行截取，当截取后的信号与发射信号在FRFT域的峰值位置相匹配时即可提取出回波信号的起始位置。仿真结果显示论文方法有较好的效果。%To extract the starting location of underwater target echo is the key of target detection and identification .In practice ,the signal received by active sonar consist of not only echo but also noise and reverberation .The echo is always sub‐merged in background noise ,so it is hard to extract the starting location .This paper introduces Fractional Fourier Transform which is short for FRFT into echo detection and uses sliding window to intercept echo .When the peak value location of the intercepted signal and the transmitted signal match in FRFT base ,we can then extract the starting location .The result of simulation shows the proposed method has great effect .