温度环境下空间遥感光学系统成像质量的检测

在离轴三反射系统热光学理论分析的基础上，利用热光学实验测试了光学系统在不同热环境下的成像质量。将实测温度代入有限元模型，计算表征镜面变形的Zernike系数。将Zernike系数输入光学设计软件，复算光学系统的理论成像质量，并与测试结果进行对比分析。结果显示，理论复算值与实验实测值相吻合，证明了理论分析的正确性。试验检测表明，系统在Nquist频率下，18℃时的静态传递函数为0．247；14～21℃时的静态传递函数为0．221～0．254，满足系统成像质量要求。

Image quality testing of space remote sensing optical system under thermal environment

On the basis of the theoretical thermal optical analysis of off-axis three-mirror systems, the image quality of a space remote sensing optical system in different thermal environments was tested by using a thermal optical experiment. After the actually measured temperature was input into finite element model, the surface aberrations of mirrors with temperature gradients were obtained using finite element analysis software, and the surfaces with aberrations were fitted with the Zernike Polynomials. Then, Zernike coefficients were input into the optical design software, and the imaging qualities of system with difference temperature gradients were ana- lyzed. Finally, the experimental results were compared. It shows that the theoretical analysis results are in a- greement with the measured results, proving that the analysis is correct. Measured Modulation Transfer Func- tions（MTF） at Nquist frequency are 0. 247 at 18 ℃ and 0. 221 -0. 254 between 14 -21 ℃ , which meet the requirement of image quality.