为提高长焦红外光学系统焦距测量的准确性, 提出一种将干涉测量、光电自准和激光跟踪技术相结合的焦距测量方法。基于光学系统波前干涉测量光路, 利用波前的power值对球面反射镜位置非常敏感的特性, 结合激光跟踪仪的空间几何量精密测量和光电自准直仪的精密测角功能, 实现长焦红外光学系统焦距的高精度测量。实验中对一理论焦距为1 520 mm的航空长焦红外光学系统进行测试, 并结合测试设备的测量精度进行误差分析, 5次测量的标准偏差为0.930 mm, 测量误差小于0.2%, 满足测试技术要求。结果表明这种方法用于长焦红外光学系统焦距的测量是合理可行的。

In order to improve the accuracy of focal length measurement for long-focus focal infrared optical system, a new method is proposed, that includes interferometry, photoelectric auto-collimation, and laser tracking technique. Based on the wavefront interferometry optical path, it can be realized that the focal length for long-focus infrared optical system is measured with high accuracy, by using the features that the power of wavefront is very sensitive to the position of spherical mirror, and combining with the high-precision position measurement function by laser tracker and the high-precision angle measurement function by photoelectric autocollimator.A long-focus infrared optical system for aerial reconnaissance was tested in the experiment, whose theoretical focal length was 1 520 mm, and the testing error was analyzed according to the accuracy of the equipments. The standard deviation of 5 measurments results was 0.930 mm, and the measurement error was less than 0.2%,meeting the test technical requirements. The experimental result shows that the method is successful and effective to measure the focal length of long-focus infrared optical system accurately.