利用干涉级次小数部分计算得到成像物镜相对焦距值，结合微小角度引起的相对位移值，实现微小角度测量的自校准。仿真计算了小数重合法的算法误差及温湿度误差，并实现了F-P间隔计算结果的修正，设计了可自校准的微小角度测量实验装置，通过测量实验得到了间隔修正前后成像物镜焦距值及微小角度测量结果。实验结果表明：在当前实验条件下，经修正后的焦距测量相对扩展不确定度从0.014减小到0.007，600″测量范围内的角度测量不确定度从0.132″减小到0.084″，微小角度测量的准确度得到有效提升。

The demand for high-accuracy measurement of micro-angle in modern industries is getting higher and higher, and its measurement methods and measurement technologies are also constantly improving. At present, The micro-angle measuring instrument with the highest accuracy in the world is the ELCOMAT HR photoelectric autocollimator produced by M?LLER-WEDEL in Germany, and its angle measurement uncertainty within the range of 300″ can reach 0.06″ (k=2). And the highest accuracy in China is the AUTOMAT 5 000 photoelectric autocollimator produced by Tianjin Automate Optoelectronics Co., which can achieve a measurement accuracy of ±0.25″ within the range of ±1 000". With the continuous improvement of the precision of micro-angle measurement, higher and higher requirements are put forward for the angle calibration, and some traditional angle calibration methods are difficult to meet the current needs. Therefore, using the self-calibration technology to realize micro-angle measurement has become a research hotspot in recent years. The current angle self-calibration technology mainly focuses on the measurement of the circumference angle with the characteristic of circle closure, and there are few studies on the self-calibration measurement of micro-angle. In the early stage, our research group proposed a micro-angle measurement system based on F-P etalon, which used the displacement of the concentric rings in the focal plane after F-P multi-beam interference ring imaging to achieve micro-angle measurement, and pointed out the possibility of using the system to realize the micro-angle self-calibration measurement. This paper provides a comprehensive review and summary of the self-calibration method for this micro-angle measurement. The key point of this self-calibration method is to use the exact fraction method to measure the exact value of the F-P etalon interval, and then accurately calculate the relative focal length of the imaging objective lens, and combine the relative displacement caused by the small angle, so as to realize the self-calibration of the micro-angle measurement. The main research work of this paper is as follows: 1) The principle and method of the self-calibration measurement of the micro-angle measurement system are systematically and detailedly sorted out, and the calculation method of exact fraction method is described in detail, and the complete micro-angle self-calibration measurement process is finally obtained. 2) Special consideration is given to the effect of the algorithm error of the exact fraction method, temperature and humidity on the measurement results of the F-P etalon. The interference image under the theoretical interval d₀ is obtained through simulation by MATLAB, and the calculated interval d₁ of the F-P etalon under this condition is obtained by using the exact fraction method, and compared with the theoretical interval d₀, the algorithm error and the temperature and humidity error of the exact fraction method are obtained, and the correction of the calculation result of the F-P interval is realized. 3) The self-calibrated micro-angle measurement experiments are carried out, and the accurate interval of the F-P etalon in the current environmental conditions is measured. Combined with the simulation method in 1), the corrected value under the current environmental conditions is obtained, and finally the corrected etalon interval is obtained, which is d '=(2 014.986 5±0.000 3) μm. The focal lengths of the imaging objective and the micro-angle measurement results before and after self-calibration are obtained. The measurement results show that under the current experimental conditions, the relative expanded measurement uncertainty of the focal length after self-calibration has reduced from 0.014 to 0.007, while the angle measurement uncertainty in 600" has decreased from 0.132″ to 0.084″, which promotes the accuracy of micro-angle measurement greatly.