相位梯度自聚焦（PGA）算法被广泛应用于SAR成像过程中，具有很好的聚焦性和稳健性。文中在对聚束SAR中的标准PGA算法进行分析的基础上，根据聚束SAR与条带SAR回波信号的不同特点，提出了适用于条带SAR的PGA算法。该算法通过选取更为合适的特显点目标及以特显点位置作为分段的依据，在条带SAR的仿真和实际成像过程中取得了良好的聚焦效果，并且具有较快的收敛速度。

The phase gradient autofocus(PGA) algorithm has been widely used in synthetic aperture radar(SAR).It has been proven to be a superior and robustness autofocus method.This paper describes a generalization of the standard PGA algorithm used in spotlight SAR,and analyses the differences between the spotlight SAR and stripmap SAR.We present a modified PGA algorithm used in stripmap SAR.New methods are employed in selecting the scatterers and segmenting the stripmap data based on the position of the scatterers.This algorithm has been demonstrated with the simulated and real stripmap SAR data and proved to be a superior method.

TN958