为了实现对拼接镜子镜之间相对曲率半径的精确测量,提高各子镜曲率半径的匹配精度，提出了一种使用Shack-Hartmann传感器和高精度球径仪测量球面子镜相对曲率半径的新方法，并建立了一个实验系统。该方法首先使用共焦调整方法使各子镜共焦，用S-H传感器测量子镜的轴向离焦量，轴向调整压电陶瓷促动器，使由传感器测得的离焦量接近于0；最后,再对子镜进行一次共焦调整之后，使用高精度球径仪来测量各子镜之间的相对曲率半径差。实验采用的拼接镜由3块对边长300 mm的正六边形子镜组成，子镜为球面，设计曲率半径为2 000 mm。分析测试结果表明，该方法测得的球面拼接子镜的相对曲率半径精度约为1 μm，该方法表明适用于大型球面拼接镜面望远镜各子镜相对曲率半径的检测。

With the aim to measure the relative curvature radius between the two segments in spherical segmented mirrors and to improve the matching accuracy of segments, a new method utilizing a Shack-Hartmann sensor and a high precision spherometer to measure the relative radius of each spherical segment is presented and an experiment system is also setup. The method firstly uses a co-focus technique to co-focus each segment; then uses the S-H sensor to measure the defocus in the optical axis direction and employs a PZT actuator behind the segments to make the defocus near zero. After the same co-focus process is undertaken again, the relative radius of each segment can be measured by the high precision spherometer. In the experiment, the segmented mirror consists of three spherical hexagonal segments with an opposite side of 300 mm and a curvature radius of 2 000 mm. The analysis and experiment indicate that the precision of the method is about 1 μm, which shows that the method is suitable for the measurement of relative curvature radius of large spherical segmented mirrors.