中文摘要：

雷达（SAR）信号相位的稳定性对于成像处理后图像的方位向分辨率的高低有至关重要的影响．由于飞行平台运动误差或湍流大气中微波传播的影响会直接导致信号相位的波动，机载SAR的方位聚焦一直是SAR成像研究中的重要内容．这里介绍一种基于相位梯度自动聚焦矫正信号相位的高分辨率机载SAR成像处理方法，利用这种方法，对真实的机载SAR信号实验数据进行成像处理．试验表明：在缺乏机载平台运动补偿系统提供飞机运动状况信息的情况下，该成像方法能够有效地估计和补偿相位误差，从而可获得方位向分辨率明显提高的机载SAR图像．

英文摘要：

Phase stability of SAR signal is essential to image azimuth resolution of coherent imaging processing. Phase fluctuations can be induced by platform motion error or microwave propagation effect in turbulent atmosphere. Thus azimuth autofocus has been an important research subject for advanced precision airborne SAR imaging processing. This paper introduces an experiment of high-resolution airborne SAR imaging based on phase gradient autofocus. This method is developed to compensate the phase error in SAR signal while the aircraft platform motion compensation system is not provided. Experiments show that the imaging algorithm based on phase gradient autofocus can effectively measure and compensate the phase error, thus obtain an obviously improved airborne SAR image in azimuth resolution.