基于去斜滤波与稀疏恢复的探干一体化系统直达波抑制技术

探测干扰一体化系统通过波形一体化设计，利用无典型雷达信号特征的干扰信号进行探测，共享波形、频率、时间、孔径等资源，极大提升了系统资源的综合利用率。然而，为实现有效干扰，探测干扰一体化波形在频段上会与对方雷达信号有所重叠，一体化设备探测回波会受到由对方雷达发射信号带来的强直达波影响，造成探测性能的严重恶化。本文考虑探干一体化系统与线性调频雷达对抗的场景，提出了两种直达波抑制算法（去斜频域滤波与稀疏恢复）。在第一种算法中，通过分数阶傅里叶变换（Fractional Fourier Transform,FRFT）估计对方线性调频直达波调频斜率，构造回波去斜函数，将直达波分量变换为点频信号后通过频率滤波进行滤除。在第二种算法中，以去斜滤波方法作为预处理步骤，针对直达波功率强时去斜滤波带来的回波能量损失问题，利用稀疏恢复的方法恢复损失信号，进一步提升了探干一体化系统的探测能力。通过仿真和实测结果验证了算法可行性。

Direct Wave Suppression Technology Based on De-slope Filtering and Sparse Recovery of Integrated Detection and Jamming System

? ?Through the integrated design of waveforms， the integrated detection and jamming system used jamming signals without typical radar signal characteristics to detect. The signals could share resources such as waveform， frequency， time， and aperture， which greatly improved the comprehensive utilization rate of system resources. However， in order to achieve effective interference， the integrated detection and jamming waveform would overlap with the other side’s radar signal in the frequency band， and the detection echo received by the integrated equipment would be affected by the strong direct wave caused by the other side’s radar transmission signal. Considering the scenario of the confrontation between the integrated detection and jamming system and the linear frequency modulation （LFM） radar， this paper proposed two methods of direct wave suppression algorithm （de-slope and frequency-domain filtering and sparse recovery）. In the first method， the echo de-slope function could be constructed by the direct LFM slope of the other side which could be estimated by fractional Fourier transform （FRFT）. After the direct wave component was converted into a point-frequency signal， it could be filtered by the frequency filtering. In the second method， the de-slope and frequency-domain filtering method was taken as the preprocessing step. Aiming at the problem of echo energy loss caused by de-slope filtering when the direct wave power was strong， the loss signal was restored by using the sparse recovery method. The detection capability of the integrated detection and jamming system had been further improved. The feasibility of the proposed algorithm is verified by simulation and results of measured data processing.