A target detection algorithm of HFSWR based on time-frequency analysis

To improve the detection accuracy of moving targets for high frequency surface wave radar (HFSWR) based marine surveillances, a target detection algorithm based on spectrum zoom and reassigned wavelet scalogram time-frequency analysis is presented in this paper. Firstly, the received signal of HFSWR is processed by the spectrum zoom technique to improve the frequency resolution for the subsequent time-frequency analysis. Then the Morlet wavelet based time-frequency analysis method is used to extract the distribution features of targets in the time-frequency plane. Moreover, in order to improve the time-frequency concentration and suppress cross term interference, the wavelet scalogram is reassigned. Finally, the suspected target area is detected accurately from the obtained time-frequency distribution map. The experimental results show that the proposed algorithm can not only effectively detect moving objects with very small differences among their Doppler frequencies, but also extract objects with Doppler frequencies near the sea clutter, thereby providing a fine and accurate dete-cting and analyzing algorithm to some suspect object areas which are not identified by the conventional target detection algorithms.