水下目标LFM回波的小波尺度谱重排及匹配检测  

Wavelet Scalogram Reassignment and Matching Detection for LFM Echoes of Underwater Target

作　　者：王强[1,2] 潘翔[1] 王孝伟[2] 

机构地区：[1]浙江大学信息与电子工程学系,浙江杭州310027 [2]中国计量学院质量与安全工程学院,浙江杭州310018

出　　处：《华南理工大学学报（自然科学版）》2010年第1期70-75,共6页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(60902095);浙江省自然科学基金资助项目(Y1090672)

摘　　要：在浅水混响限条件下,为提高水下小尺度目标检测性能,结合宽带线性调频(LFM)信号回波目标信息量大、混响背景相关性弱的特点,提出对目标宽带回波进行时频谱重排压制混响,再进行匹配检测的方法.通过比较目标回波的短时傅里叶变换和小波尺度重排谱时频表征,发现小波尺度谱重排能较好地实现目标信号和耦合混响的分离.再结合匹配滤波的定位特性设计基于小波尺度重排谱的时频匹配检测器.仿真和测试数据分析表明,文中方法的检测性能优于传统匹配滤波约4 dB,在混响背景下,时频匹配滤波器仍能对水下目标进行有效定位,且能较好抑制旁瓣.In order to improve the detection performance of small-scale underwater targets in a shallow-water reverberation-limited environment, broadband linear frequency-modulated （LFM） signals containing vast target information and weak reverberation background correlation are used to perform a time-frequency spectrogram reassignment and a matching detection for the target broadband echoes. Then, the time-frequency features of target echo respectively obtained by the short-time Fourier transform （STFY） and by the wavelet scalogram reassignment are compared, finding out that the reassignment helps to effectively separate the target signal and the coupled reverberation signal. Moreover, a time-frequency matching detector based on wavelet scalogram reassignment is designed according to the matched filter features. Simulated and test results indicate that the proposed method is superior to the traditional matched filtering method with a gain increase of about 4 dB, and that it can accurately locate the underwater targets in reverberation-limited area with strong side-lobe suppression.

关 键 词：线性调频信号 小尺度目标 主动探测 小波尺度谱 谱重排 

分 类 号：TP391.4[自动化与计算机技术—计算机应用技术] TB565.2[自动化与计算机技术—计算机科学与技术]