Abstract:

The returns of slow and dim targets,which have high energy and a wide frequency spectrum,are often submerged in the sea clutter.This paper proposes a new SVD-FRFT-based sea clutter suppression method using time-frequency information.The proposed method adopts the strategy of block processing and overall judgment.First,the long echo sequence is divided into sub-pulse blocks,with the first Q-order signal components of each sub-pulse block being respectively extracted and inter-block signal correlation performed to realize the preliminary separation of the target and clutter.Then an adaptive segmented SVD-FRFT processing is used to achieve further purification of the signal components of each order.Finally,the normalized ime-frequency ridge quadratic fitting error is used to judge the components of each order.In this way,the target is retained while the sea clutter is suppressed.The effectiveness and robustness of this approach is verified by the real sea clutter data.Compared with the classical sea clutter suppression methods,the proposed method can effectively suppress the sea clutter and extract target signals regardless of signal-to-clutter ratio(SCR),especially for the multi-target.

Key words: sea clutter suppression, target detection, singular value decomposition, fractional Fourier transform