相位梯度自聚焦（PGA）算法广泛应用于合成孔径雷达的运动误差补偿。激光信号波长比微波信号小3~4个数量级，因而在合成孔径激光成像过程中，实验平台的振动会引入极大的相位误差，导致成图质量下降。在合成孔径激光雷达（SAL）成像过程中应用PGA算法，并针对激光波段信号的特点对传统的PGA算法在加窗方法上加以改进。实现了SAL样机在室外64 m成像距离下的快速合成孔径激光成像的实验验证，证明PGA算法能够实现散焦数据中相位误差的精确补偿，且改进后的PGA算法在达到同样补偿效果的前提下，迭代次数更少。

Phase gradient autofocus (PGA) algorithm can be used to estimate and correct phase errors effectively in echo signals of synthetic aperture lidar. The wavelength of laser is three to four magnitudes shorter than that of the microwave, so the vibration of experimental platform can bring great phase errors during the process of synthetic aperture lidar (SAL) imaging, which results in the reduction of imaging quality. To improve the image quality, a PGA algorithm with an improved method of windowing compared to the conventional PGA method is applied in SAL and is experimentally verified by an SAL demonstrator on a 64 m-distance-target to not only realize the accuate compensation to the phase errors in the defocusing data, but also have fewer iteration times and the same compensation effect.