Journal of South China University of Technology (Natural Science Edition) ›› 2010, Vol. 38 ›› Issue (1): 70-75.doi: 10.3969/j.issn.1000-565X.2010.01.014

• Electronics, Communication & Automation Technology • Previous Articles     Next Articles

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

Wang Qiang 1.2  Pan Xiang1  Wang Xiao-wei2   

  1. 1. Department of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China; 2. Department of Quality and Safety Engineering, China Jiliang University, Hangzhou 310018, Zhejiang, China
  • Received:2008-12-12 Revised:2009-04-25 Online:2010-01-25 Published:2010-01-25
  • Contact: 王强（1976-），男，博士，中国计量学院副教授，主要从事相控超声无损检测、传感器阵列信号处理研究． E-mail:wangtulip@ yahoo.com.cn
  • About author:王强（1976-），男，博士，中国计量学院副教授，主要从事相控超声无损检测、传感器阵列信号处理研究．
  • Supported by:

    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）

PDF

1030

Abstract:

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.

Key words: linear frequency-modulated signal, small-scale target, active detection, wavelet scalogram, spectrogram reassignment