Detection and extraction of marine target with micromotion via short-time fractional Fourier transform in sparse domain

The micro-Doppler (m-D) signatures can describe the refined motion characteristics of a marine target, which are helpful for target detection and recognition. Due to the complex sea clutter and m-D of marine target, traditional detection methods using time-frequency analysis have great limitations on accuracy and computational cost. In this paper, the micromotion signal model of sea surface target is firstly established according to the length of observation time. Then a novel detection and m-D extraction method is established via sparse time-frequency analysis, i.e., short-time fractional Fourier transform in sparse domain (SSTFRFT). The definition and calculation are described in detail. Finally, experimental results using real radar data, i.e., S-band searching radar (SSR) data, indicate that the proposed method can achieve excellent detection performance and lower computational cost with higher accuracy compared with the traditional methods.