杂波背景下的时距联合检测前聚焦方法研究

传统相干雷达信号处理流程对跨距离单元走动的目标一般采用脉冲压缩与Radon傅里叶变换(RFT)先后级联的处理方法，但级联方法存在以下问题:一是对高速目标能量积累的过程中目标峰值位置偏移甚至主瓣展宽、增益下降、旁瓣增高；二是缺少有效杂波抑制，影响弱目标检测。为此，该文借鉴多维信号联合以及杂波抑制的思想，提出一种杂波背景条件下将脉冲压缩、RFT与自适应杂波抑制联合的时距联合检测前聚焦方法(A-PCRFT)。该方法首先将脉内时间(快时间)与脉间时间(慢时间)两个雷达信号处理维度相联合，引入与高速目标相对应的二维导向矢量，补偿脉内和脉间的多普勒频移；然后根据辅助数据估计脉冲压缩前的杂波协方差矩阵；最后根据杂波协方差矩阵和导向矢量确定最优滤波器权矢量。在距离-速度二维空间中，该方法能有效地抑制杂波，同时对目标能量进行最佳聚焦。仿真结果表明，该方法与先脉冲压缩后自适应Radon傅里叶变换(ARFT)的级联方法相比性能更优。 

Time-Range Focus-Before-Detect Method in Clutter Background

The traditional coherent radar signal processing generally adopts the cascaded processing method of pulse compression and Radon-Fourier Transform (RFT) for a target moving across the range cell. However, the cascaded processing exhibits the following problems: first, during the energy integration of a high-speed target, problems including the offset of the target peak, even broadening of the main lobe, gain reduction and increases in the side lobes will occur; second, the lack of effective clutter suppression affects the detection of weak targets. Based on the multi-dimensional signal combination and clutter suppression, this paper proposes a Time-Range Focus-Before-Detect method (Adaptive-Pulse Compression Radon-Fourier Transform, A-PCRFT) in clutter background, which combines the pulse compression, RFT and adaptive clutter suppression. First, the method combines the two radar signal processing dimensions of intra-pulse time (fast time) and inter-pulse time (slow time). The two-dimensional steering vector corresponding to the high-speed target is introduced to compensate for the intra-pulse time and inter-pulse Doppler shifts; Then, the clutter covariance matrix before pulse compression is estimated based on the secondary data; Finally, the optimal filter weight vector is determined according to the clutter covariance matrix and the steering vector. This method can effectively suppress the clutter and focus the target energy simultaneously in the range-velocity space. Simulation results show that this method is superior to the cascaded method, which adopts the pulse compression and adaptive Radon–Fourier transform.