中文摘要：

天波超视距雷达（over-the-horizon radar，OTHR）中，机动目标信号存在频谱扩展，导致目标检测性能下降。强的海杂波进一步增加了机动目标的检测难度。针对该问题，考虑到海杂波信号能量主要集中在零频附近，而且可以建模为一个自回归（auto-regressive，AR）过程，用 AR 滤波器抑制海杂波；考虑到机动目标信号近似为线性调频信号，而分数阶傅里叶变换（fractional Fourier transform，FRFT）能有效积累线性调频信号的能量，因此采用 FRFT 算法估计目标运动参数，实现机动目标检测；在此基础上用分级迭代的 FRFT 进一步降低运算量；针对多目标检测问题，用“CLEAN”方法逐个检测机动目标。仿真结果表明，与已有的离散多项式变换（dis-crete polynomial transform，DPT）算法相比，本文算法可以更好地适用于多目标检测；与 Radon-Wigner 变换算法相比，本文算法可以达到更高的参数估计精度。

英文摘要：

In the over-the-horizon radar （OTHR）,the Doppler spread in the maneuvering target echo re-duces the detection performance.The strong sea clutter further increases the detection difficulty.Considering that the sea clutter is mainly near zero frequency and can be modeled as an auto-regressive （AR）process,an AR filter has been used to suppress the sea clutter.Considering that fractional Fourier transform （FRFT）can effec-tively concentrate chirp signals,and the maneuvering target signal is approximately a chirp signal,the FRFT-based method has been applied in the maneuvering target detection and parameter estimation.The grading itera-tive method is used for fast calculation,and the shading problem between multiple targets is solved through the“CLEAN”method.The proposed algorithm can be better applicable to multi-target detection compared with the discrete polynomial transform （DPT）method,and has higher parameter estimation accuracy than the Radon-Wigner transform （RWT）method.Simulation results show that the proposed algorithm improves the maneuve-ring detection ability of OTHR,and can estimate the parameter of the target more accurately.