机载宽视场大相对孔径成像光谱仪

Airborne imaging spectrometer with wide field of view and large relative-aperture

根据宽视场大相对孔径成像光谱仪的应用要求和技术指标,采用离轴Schwarzschild望远成像系统和双Schwarzschild光谱成像系统匹配的结构型式,设计了一个视场为28°、相对孔径为1/2.5、工作波段为0.4～1 μm的机载成像光谱仪光学系统;根据双Schwarzschild光谱成像系统的像散校正条件计算了初始结构参数.然后,利用光学设计软件ZEMAX-EE进行了光线追迹和优化设计,并对设计结果进行了分析与评价.结果显示：光谱成像系统中心波长和边缘波长88％以上的能量集中在一个探测器像元内;谱线弯曲和谱带弯曲均小于像元的5％,便于光谱和辐射定标;成像光谱仪全系统在各个波长的光学传递函数均达到0.59以上,完全满足设计指标要求.该成像系统体积小、重量轻,非常适合航空遥感应用.

According to the requirements of an airborne imaging spectrometer for the wide angle and large relative-aperture,an optical system for the airborne imaging spectrometer was designed using an off-axis Schwarzschild telescopic system and a double-Schwarzschild spectral imaging system.The imaging spectrometer has specifications by a field of view of 28°,a relative-aperture of 1/2.5,and working waveband from 0.4 μm to 1 tm.Based on the astigmatism-correction condition of doubleSchwarzschild spectral imaging system,the initial parameters were calculated.Then,the ray tracing and optimization design were performed by ZEMAX software.The analysis and evaluation on the design show that 88％ of the encircled energy for centric and edge wavelengths is within one pixel; both smile and keystone are less than 5％ of the size of one pixel,so it is easy for spectral and radiation calibrations.Moreover,the MTF of imaging spectrometer is more than 0.59 for different wavelengths,which satisfies the requirements of specifications.As the spectrometer has a smaller volume and lower mass,it is suitable for airborne remote sensing.