温度对星载成像光谱仪谱线漂移的影响

Thermal Effect on Spectral-Line Shift of Spaceborne Imaging Spectrometer

为了研究温度对成像光谱仪谱线漂移的影响,分析了谱线漂移与光谱成像系统各镜面刚体位移之间的关系,建立了温度对成像光谱仪谱线漂移影响的理论模型,通过软件仿真和热光学试验对理论模型进行了验证和修正。基于线性光学理论建立了镜面刚体位移对谱线漂移影响的数学模型,使用蒙特卡罗法对理论模型进行了数值仿真验证;采用有限元法求解了温度载荷下各镜面的刚体位移,在Matlab软件环境下利用Code V的API函数对变形后的光学系统进行了光线追迹,求解了镜面刚体位移导致的谱线位置变化,研究了成像光谱仪的谱线漂移特性,得到了温度载荷作用下的谱线漂移模型;通过热光学试验对理论模型进行了验证和修正。结果表明,在8℃～28℃范围内,谱线在光谱方向仅发生整体平移,没拉伸或压缩效应;基于线弹性理论和线性光学模型建立的理论模型与试验结果吻合较好,最大偏差不超过12%,修正后的谱线漂移模型相对误差小于5%,绝对精度优于0.2pixel。

To study the thermal effect on spectral-line shift of spaceborne imaging spectrometer, the relation between spectral-line shift and rigid-body motion of the mirror is analyzed, and the theoretical model, which is verified and corrected by simulation and thermal-optical test, is established to describe the spectral-line shift property. The mathematical model based on linear optics model is established to describe the relation between spectral-line shift and rigid-body motion of the mirror, and the Mont Carlo method is employed to do the verification. The finite element analysis （FEA） method is used to get the rigid-body motion of mirror under different thermal loads. Code V API functions are used, in Matlab environment, to calculate the variation of the spectral line caused by rigid-body motions, and the spectral-line shift property is studied at the same time. The spectral-line shift model is corrected and verified by thermal-optical test. The results show that spectral-line integral deviation without extension and compression under the temperature from 8 ℃ to 28 ℃. Spectral-line shift values obtained by the thermal optical test are well coincident with the ones calculated by theoretical model. The maximum deviation between theoretical analysis and thermal optical test is not exceeding 12 %, The new spectral-line shift model, corrected by the test data, realizes a high precision spectral line shift forecasting. The relative error is less than 5 % and the absolute accuracy is better than 0.2 pixel.