如何提高子孔径拼接干涉测量精度是子孔径拼接系统的关键问题。针对一维平面子孔径拼接系统，分别采用两两拼接算法和误差均化拼接算法，进行拼接位移台定位误差、参考面面形误差和随机噪声对拼接精度影响的数值仿真与分析。仿真结果表明，对于平面拼接系统，参考面高阶误差、随机噪声对拼接精度影响较小，高阶误差的影响略大于随机噪声的影响；参考面低阶误差(二阶项误差)在拼接过程中会累积放大，是平面拼接干涉测量的主要误差来源，误差均化拼接算法不能有效控制参考面低阶误差的拼接累积误差；两两拼接算法与误差均化拼接算法得到基本相同的拼接结果。对450 mm×60 mm的平面镜进行了15个子孔径的拼接测量，去除参考面低阶误差面形前后，拼接结果与大口径干涉仪的测量结果偏差从λ/3［峰谷值(PV)，λ=632.8 nm］减小至λ/45(PV)。

How to improve the sub-aperture stitching interferometry accuracy is critical for the sub-aperture stitching system. For one-dimensional flat sub-aperture stitching system, the influence of the stitching stage positioning error, the reference surface error and random noise on the stitching accuracy is simulated and analyzed of data based on both double sub-aperture stitching algorithm and error averaging stitching algorithm. The simulation results show that, the flat stitching system is insensitive to the high order errors of reference surface and the random noise. The stitching error of the high order errors of reference surface is a little larger than that of the random noise. The low order errors (the second order errors) of the reference surface will be accumulated and enlarged during the stitching process, which is the main error source for the flat stitching interferometry. The stitching accumulation error of the low order errors of the reference surface cannot be effectively controlled by the error averaging stitching algorithm. The double sub-aperture stitching algorithm and the error averaging stitching algorithm almost get the same stitching result. A flat mirror with aperture of 450 mm×60 mm is tested by 15 sub-apertures. The deviation between the stitching result and the test result of a large aperture interferometer is reduced from λ/3 ［peak valley value (PV), λ=632.8 nm］to λ/45 (PV) after removing the low order errors of the reference surface.