温度对某机载成像光谱仪谱线漂移的影响

Thermal Effect on Spectral-Line Shift of a Airborne Imaging Spectrometer

为了研究温度对机载成像光谱仪谱线漂移的影响,分析了机载环境下仪器温度载荷的特点、作用机理和表现形式,研究了光谱仪的谱线漂移特性。根据机载环境下温度载荷特点,利用有限元法,结合最小二乘法和坐标转换法,计算了光学系统各镜面在温度载荷作用下面形变化和刚体位移。对变形后的光学系统进行了光线追迹,研究了其谱线漂移特性。通过热光学实验和飞行成像期间光谱定标实验验证了理论分析。热光学实验表明,在±10℃温度变化范围内,谱线在光谱方向仅发生整体平移,没有拉伸或压缩效应。在飞行期间的定标实验中,其平均谱线偏移量为0.248 nm,满足定标精度的1/3(定标精度为1 nm)要求。后续成像不需要再进行光谱定标或光谱修正。

In order to study the thermal effect on spectral- line shift of aerial imaging spectrometer, the characteristics, mechanism and manifestation of the instrument temperature load airbrone environment are analyzed, and the spectral-line shift characteristics of the spectrometer are studied. According to the characteristics of the temperature load in airbrone environment, the finite element method is taken to calculate the deformation and rigid body displacement of the mirror of the optical system at a temperature load, combined with the least squares method and coordinate transformation method. Ray tracing to the deformed optical system are carried out and its spectral-line shift characteristics are studied. The thermal-optical test and calibration test during flight is taken to prove the theoretical analysis. The results show that within the range of ±10 ℃, there is only shifting in the spectral direction, no tension or compression effects. During the calibration test of flight, the average line offset is 0.248 nm, satisfies the need of 1/3 of the accuracy（calibration accuracy is 1 nm）. No further spectral calibration or correction is needed in the later imaging.