根据波像差理论，推导了光学合成孔径成像系统单个子孔径存在各种像差时波面方差与子孔径数(N)的关系。推导结果表明，piston误差对系统的影响最大，其次是离焦误差、倾斜误差、球差、彗差和像散。运用离焦误差对piston误差、球差和像散进行像差平衡，其效果显著，特别是球差引起的波面方差下降90%。系统各项像差系数随子孔径数的增加而降低；当子孔径数大于6时，各像差系数变化缓慢。根据瑞利判据，计算N(N≤6)个子孔径合成系统的像差允限和相应的3孔径系统的斯特列尔比。

Based on the wave aberration theory,the relation between wave surface variance and the number of subapertures is derived when some aberration exists in single subaperture of the optical synthetic aperture imaging system. The derivation result shows that the most sensitive aberration is piston error,and then the defocusing error,tilt error,spherical aberration,coma and astigmatism. To improve the quality of the image,the defocusing error was used to balance the piston error,spherical aberration and astigmatism,and the results were significantly improved,especially the wave surface variance caused by spherical aberration was decreased by 90 %. The coefficients of every aberration were decreased with the increase of the number of subapertures (N),but changed slowly when N was greater than 6. The aberration tolerance of synthetic aperture imaging system with N (N≤6) subapertures and Strehl ratio of the system with 3 subapertures were calculated according to Rayleigh criterion.