介绍了相位差法基本原理，应用相位差法估算稀疏孔径成像系统各子镜误差，分析基准子镜对相位差法计算结果的影响。以Golay3稀疏孔径为例，提出利用稀疏孔径成像系统中的每个子镜单独对目标物成像，计算每个子镜的焦面成像图与原目标物图的算术平均值标准偏差（AMSD），将AMSD值最小的子镜设为基准子镜。分析在实际运用中基准子镜误差大小对系统剩余子镜误差估算精度的影响，最后讨论离焦量对相位差法计算精度的影响。理论仿真表明：利用相位差法对稀疏孔径成像系统各子镜误差进行估算时，必须先确定基准子镜；AMSD值越小，对应子镜的误差也越小，将其作为基准子镜，利用相位差法计算出的系统剩余子镜的误差也越小；在相位差法的计算过程中，改变离焦像的离焦量对计算结果影响不明显。

The principle of phase diversity(PD) is firstly introduced. The effect of the benchmark sub-mirror of sparse aperture imaging system on PD is illustrated. Taking Golay3 sparse aperture as an example, the object is imaged by each sub-mirror of the imaging system. The arithmetic mean standard deviation(AMSD) between images of each sub-mirror and the original object is calculated, and the sub-mirror with minimum AMSD value is selected as the benchmark sub-mirror. The influence of errors of the benchmark sub-mirror which are unknown practically on the accuracy of error estimation of the other sub-mirrors is analyzed. The impact of the defocus amount on the results of PD is also discussed. It is shown that the benchmark sub-mirror must be confirmed before error estimation of the other sub-mirrors of the sparse aperture imaging system with PD. The smaller the AMSD value is, the smaller the error of the corresponding sub-mirror is, the smaller the error of the residual sub-mirrors in the system calculated by PD method is, while the variation of the defocus amount has little influence on PD results.