间歇采样转发干扰下基于稀疏 LVD的高速目标检测
High Speed Target Detection Based on Sparse LVD in Interrupted Sampling Repeater Jamming
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摘要: 间歇采样转发干扰作为雷达工作环境中一种广泛应用的干扰,通过对雷达发射信号进行多次采样和转发,在接收端可形成假目标使得雷达系统难以检测到真实目标。本文分析了高速运动目标的雷达回波特点,鉴于目标信号具有线性调频信号形式,采用吕氏分布(Lv’s Distribution,LVD)方法进行目标检测,然而在间歇采样转发干扰下该方法失效,无法检测到真实目标。针对高速运动目标在间歇采样转发干扰下的检测和参数估计问题,提出了稀疏LVD的高速目标检测方法。分析了间歇采样转发干扰的时域特征,考虑到间歇采样转发干扰具有时域采样不连续的特点,利用能量函数设置门限提取雷达回波中未受干扰影响的部分目标信号,对部分目标回波信号计算对称参数瞬时自相关函数并矢量化表示。然后利用线性调频Z变换矩阵和快速傅里叶变换矩阵构造出稀疏LVD表示模型,将高速目标检测问题转换为中心频率-调频斜率域上的稀疏求解问题。最后利用正交匹配追踪算法获得稀疏解,实现高速运动目标检测和参数估计。仿真实验结果表明,所建立的稀疏LVD表示模型正确有效,在间歇采样直接转发干扰和间歇采样重复转发干扰两种情况下稀疏LVD方法均可准确检测目标,具有良好的目标检测和参数估计性能。Abstract: Interrupted sampling repeater jamming, prevalent in radar environments, samples and retransmits portions of the transmitter signal to create false targets on the radar receiver, thereby hindering the detection of true targets. Considering that high-speed radar targets are characterized by linear frequency modulation signals, the Lv’s distribution (LVD) algorithm is typically employed for detection. However, this method is rendered ineffective in scenarios involving interrupted sampling repeater jamming. To solve this problem, a novel sparse LVD for a high-speed target detection method is proposed. This method exploits the discontinuity in the time domain of sampling repeater jamming. It extracts the undisturbed portion of the high-speed target’s radar echo signal using an energy function-based threshold. After that, the parametric symmetric instantaneous autocorrelation function of a signal is established for vector representation. Subsequently, the sparse LVD representation model is constructed using the chirp-z transform and fast Fourier transform matrices, which transform high-speed target detection into a sparse solution problem in the centroid frequency-chirp rate domain. After that, the orthogonal matching pursuit (OMP) algorithm is used to obtain the sparse solution. Finally, high-speed moving target detection and parameter estimation are achieved. Simulation experimental results show that the proposed sparse LVD representation model is accurate and effective, and the proposed method can solve the problem of high-speed moving object detection in interrupted sampling direct repeater jamming and interrupted sampling periodic repeater jamming situations accurately, and it has good target detection and parameter estimation performance.