在子孔径拼接系统中, 各子孔径之间的倾斜与位移对整个系统的成像质量有直接影响. 本文应用动态光学理论中等效节点概念, 根据各个子孔径倾斜及轴向与垂轴位移位移时等效节点也将发生相应移动的原理, 利用拼接元件形成像点的位移引起的各个子镜形成像点叠加误差形成的弥散圆尺寸变化之间的关系, 简化了子孔径倾斜与位移对拼接系统像质影响的分析与计算.通过在子孔径拼接原理样机结构设计与公差分析中的应用，得出原理样机的倾斜公差为4 μrad，位移公差为6 μm，使原理样机的子孔径装配调整得到了有效控制.

In sub-aperture stitching system, image quality will be affected directly by tilt and shift errors of sub-apertures. The equivalent nodal point concept of dynamic optics was applied. During alignment of sub-aperture stitching system, if the sub-aperture was tilted and shifted, the circle center of sub-aperture would be tilted and shifted consequently. The equivalent nodal point will shift would sub-apertures. The spot size variation due to sub-apertures image displacement was analyzed in detail. The effect of sub-aperture tilt and shift on image quality in stitching system was simplified with equivalent nodal point concept. Through application in structure design and tolerance analysis of sub-aperture stitching prototype, the tilt tolerance and displacement tolerance is 4 μrad and 6 μm respectively. Consequently the alignment tolerance was controlled effectly in stiching prototype.