星载大气监测光谱仪高精度星上定标技术  

High Precision On-board Calibration for Spaceborne Atmospheric Monitoring Spectrometer

作　　者：李碧岑[1] 李明[1] 徐彭梅[1] LI Bicen;LI Ming;XU Pengmei(Beijing Institute of Space Mechanics ＆ Electricity, Beijing 100094, China)

机构地区：[1]北京空间机电研究所,北京100094

出　　处：《航天返回与遥感》2018年第3期60-69,共10页Spacecraft Recovery & Remote Sensing

基　　金：国家重大科技专项工程

摘　　要：大气成分的高精度反演及应用对星载超光谱载荷的辐射精度和光谱精度均提出了更高要求,且随着遥感器运行寿命的不断延长,需建立高精度、高稳定的星上定标系统。文章介绍了一种满足大气监测光谱仪高精度定标要求的星上定标技术,结合时间调制型傅里叶变换光谱仪的技术特点,制定了星上绝对辐射定标、仪器线形函数ILS测量和光谱定标的方案。采用太阳漫反射板定标法实现全口径、全视场、全光路绝对辐射定标,定标漫反射板在光谱仪光路的最前端将太阳光谱引入,通过已知的大气层外太阳光谱照度和地面标定的漫反射板双向反射分布函数BRDF确立星上绝对辐射定标基准。设置参考漫反射板进行在轨性能衰减的监测和校正,采用的QVD漫反射板具有高稳定性,可保证全寿命周期内星上绝对辐射定标精度优于5%。星上设置单色稳频激光器对光谱仪的仪器线形函数进行定期监测,以评估光谱仪的光谱分辨率等光学性能的在轨状态。利用太阳光谱和大气光谱中的特征谱线进行在轨波长校正。Radiometric accuracy and spectral accuracy should be very high for spaceborne hyperspectral payload applied in atmospheric composition retrieval. With extension of the lifetimes of spaceborne optical sensors, it is required to establish an on-board calibration system with high accuracy and high stability. The calibration techniques which can meet the high on-board calibration accuracy for atmospheric monitoring spectrometer are described in this paper. According to the characteristics of time modulated Fourier transform spectrometer, the methods of absolute radiometric calibration, instrument line shape（ILS） measurement and spectral calibration are presented. Solar diffuser is used to realize the absolute radiometric calibration on orbit covering full aperture, full field of view and whole detecting link of instrument. The calibration diffuser in front of the optical path of the spectrometer reflects the sunlight into the instrument, and the standard radiance is obtained using the known exoatmospheric solar irradiance and the BRDF（bidirectional reflectance distribution function） of the diffuser calibrated on ground. And another diffuser as a calibration reference is used to monitor and correct the degradation and variation of the calibration unit and the instrument. The absolute radiometric calibration accuracy in total life time is better than 5% by use of Quasi Volume Diffuser（QVD） which have the advantage of very stable optical performance in space. Monochromatic lasers are employed for regular ILS measurement from which the on-orbit status of optical performance like spectral resolution can be evaluated. Spectral lines in solar spectrum and atmospheric spectrum are used to correct the wavelength shift of instrument.

关 键 词：漫反射板 仪器线形函数 波长校正 绝对辐射定标 大气监测光谱仪 航天遥感 “高分五号”卫星 

分 类 号：V447.1[航空宇航科学与技术—飞行器设计]