短脉冲非相参雷达的逆合成孔径成像及其稀疏恢复成像技术

短脉冲非相参雷达(NCSP)的辐射源输出微波脉冲持续时间短，针对于高速运动目标而言，其脉冲持续时间内的目标运动可忽略不计，对回波信号不需进行专门的脉冲内运动补偿。为了利用短脉冲非相参雷达信号进行逆合成孔径雷达成像，该文应用补偿相参处理的方法，去除辐射信号包络时间不确定性和初始相位的不确定性影响，在常规方法进行包络对齐和初相补偿后可利用距离-多普勒(RD)方法进行逆合成孔径雷达成像，仿真验证了补偿后信号成像的可行性。然而，短脉冲非相参雷达的载频随机抖动的因素会导致距离-多普勒成像结果在多普勒维度产生随机调制的旁瓣，影响成像的质量。利用稀疏恢复技术，在成像空间中对目标的散射中心进行稀疏重构，利用正交匹配追踪(OMP)算法和稀疏贝叶斯学习(SBL)算法进行成像，从而实现了抑制非相参因素引起的成像旁瓣，改进了成像质量，通过仿真验证了方法可行性。

Inverse Synthetic Aperture Radar Imaging with Non-Coherent Short Pulse Radar and Its Sparse Recovery

The microwave source of Non-Coherent Short Pulse (NCSP) radar transmits short pulse. Thus, for high velocity targets, the motion effect in the pulse duration can be neglected, and the echo signal does not need special motion compensation. In order to use the NCSP radar signal for Inverse Synthetic Aperture Radar (ISAR) imaging, the compensation coherent processing method is applied to removing the uncertainty of the envelope time and the initial phase uncertainty. Assuming that the echo is envelope-aligned and initially compensated by conventional methods, ISAR radar imaging can be performed using the Range-Doppler (RD) method, subsequently. The simulation verifies the feasibility of the compensation signal ISAR imaging. However, the carrier-frequency random jitter factor of NCSP radar causes random-modulated sidelobes in the Doppler dimension, which affect imaging quality. In this paper, the sparse recovery technique is used to perform sparse reconstruction of the target scattering center in the imaging space. The Orthogonal Matching Pursuit (OMP) algorithm and the Sparse Bayesian Learning (SBL) algorithm are used as the recovery algorithm for imaging simulation experiments. The simulation results show that the sparse recovery technique can suppress the imaging sidelobes caused by non-coherence and improve the imaging quality.