机载前视合成孔径雷达Chirp Scaling成像算法研究

Research of Chirp Scaling Imaging Algorithm for Air-borne Forward-looking SAR

针对目前机载侧视合成孔径雷达(SAR)无法对飞行路线正前方进行高分辨率成像的问题,该文研究了一种新型机载前视SAR,分析了前视SAR的工作原理和方位分辨率提高的可行性。基于空间几何模型和回波信号形式,推导并给出了适用于机载前视SAR成像的chirp scaling算法,给出了各相位补偿因子表达式及算法实现步骤。模拟了前视SAR点目标回波数据,并利用该方法对分布于场景中心及边缘的点目标阵进行了成像仿真,分析了成像效果,成像质量指标与理论值基本吻合,证实了算法的有效性。

Based on the problem that side-looking SAR can not image in flight direction with high azimuth resolution, an innovative forward-looking SAR system is studied, The operation mechanism and feasibility of high azimuth resolution are analyzed. According to the spatial geometry and the model of echo signal, chirp scaling algorithm is proposed for forward-looking SAR. The phase compensation factors and realized steps of algorithm are given. Raw data of forward-looking SAR is simulated, and image is achieved by using the chirp scaling algorithm proposed in this paper. The imaging effect is analyzed, and imaging quality is consistent with theory value. Simulation results demonstrate the validity of the algorithm.