小型辐射定标光学系统的光机热集成分析

卫星遥感器辐射定标光机系统在模拟空间环境下的热学光学特性会影响辐射定标试验的精度。文章针对离轴抛物镜和辅助平面反射镜组成的小型定标光学系统，利用光机热集成分析技术建立其有限元模型，在模拟空间环境下进行热变形分析；选用在单位圆内正交的Zernike多项式作为基底函数，采用最小二乘法完成了离轴抛物镜面形的拟合；将相关数据读入光学软件，分析了该系统在模拟空间环境下的像质变化。结果表明:温度梯度对定标光机系统的影响主要表现在光学平台的刚性位移，对抛物镜面形影响非常小，光学系统像质变化量约为λ/37。最后，通过与刀口仪法的像质原位测量结果对比，证明了光机热集成分析结果的准确性。

Optical structural and thermal integrated analysis of a small radiometric calibration optical structural system

Thermal and optical performance of the radiometric calibration optical structural system under space simulation conditions can affect the precision of the radiometric calibration test for satellite IR remote sensor. In this paper, a finite element model of radiometric calibration optical structural system is built, which consists of an off-axis paraboloid mirror and a secondary mirror. It is convenient to use the orthogonal Zernike annular polynomials as the data transmission tool. Firstly, the least squares method is used for the polynomial fitting. Secondly, the Zernike coefficients are input into the ZEMAX software and the imaging quality of the optical system under space simulation conditions is analyzed. The results show that the thermal gradient of the optical structural system has an important effect on the rigid displacement of the optical bracket, but not so much on the off axis paraboloid shape. The imaging quality error is about λ/37. By comparing with the results of accurate in-situ measurements of imaging quality parameters by Foucault tester, the results of the thermal structural optical integrated analysis in this paper are validated.