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分析了谱线漂移在地面辐射定标、星上辐射定标和在轨对地观测等环节对成像光谱仪辐射测量的影响,建立了从实验室辐射定标到星上辐射定标再到在轨对地观测全过程的辐射传递模型,并通过仿真分析求解了成像光谱仪入瞳处辐射测量不确定与谱线漂移之间的关系。结果表明,谱线漂移导致的辐射测量误差与谱线漂移量和入瞳辐亮度的分布梯度成正比;光谱带宽偏差对测量精度的影响程度较中心波长误差高一个数量级。对于可见近红外(VNIR)波段平均光谱带宽10nm、短波红外(SWIR)波段平均光谱带宽20nm的典型成像光谱仪,要保证谱线漂移引起的辐射测量不确定度小于6%,实现成像光谱仪在轨观测时入瞳处的辐射测量绝对精度优于10%,可见近红外波段中心波长偏差应不大于2nm,光谱带宽偏差应不大于0.1nm,短波红外波段中心波长偏差应不大于3nm,光谱带宽偏差应不大于0.1nm。
The effects of spectral line drift on the radiometric measurement of imaging spectrometer were analyzed in the aspects of radiation calibration on the ground, radiation calibration on the satellite and on-orbit observation, and the radiometric calibration of the imaging spectrometer was established. To the whole process of earth observation radiation transfer model, and through simulation analysis of the imaging spectrometer at the entrance pupil radiation measurement uncertainty and spectral drift between the relationship. The results show that the radiation measurement error caused by spectral shift is proportional to the spectral shift and the distribution gradient of entrance pupil radiance. The influence of spectral bandwidth deviation on measurement accuracy is one order of magnitude higher than the central wavelength error. For a typical imaging spectrometer with an average spectral bandwidth of 10 nm in the visible-near-infrared (VNIR) band and an average spectral bandwidth of 20 nm in the SWIR band, a radiation spectrometry uncertainty of less than 6% due to spectral drift is achieved, enabling in-orbit imaging spectroscopy The absolute accuracy of the radiation measurement at the entrance pupil is better than 10%. Therefore, the deviation of the central wavelength in the near-infrared band should not exceed 2 nm, the deviation of the spectral bandwidth should not exceed 0.1 nm, the deviation of the central wavelength in the infrared band should not exceed 3 nm, Not more than 0.1nm.