Sea clutter suppression algorithm in low SCR based on improved fractional Fourier transform

Sea clutter suppression and target detection under complex sea states in low signal-to-clutter ratio (SCR) is the key of current maritime detection research. The target extraction ability of most algorithms is mostly based on accurate modeling of sea clutter, but sea clutter is complex and unstable, which is difficult to accurately model, especially in poor sea states. According to the characteristics of the target echo signal, this paper introduces intrinsic time-scale decomposition (ITD) to preprocess the echo signal to improve the algorithm effect under low SCR. Secondly, the too much cycles in searching for optimal transformation in fractional Fourier transform (FRFT) is improved to reduce the calculation cost and extract the target signal accurately. The effectiveness and reliability of the proposed method are verified by simulation and measured experiments under different SCR and different transform order interval & DBLBOND;p, and the sea clutter suppression ability and target extraction accuracy are measured by parameters such as the detection rate, the gain of SCR and the running time. Compared with FRFT-related algorithms, the results indicates that the proposed algorithm can effectively suppress sea clutter and accurately extract target signal even at SCR = -25 dB in less than half the running time of the comparison algorithms.