太阳是地球唯一外部能量输入源，长期精准监测空间太阳总辐照度（TSI）可为气候变化预测、环保政策制定提供科学依据。目前我国太阳辐射遥感仪器的TSI定标绝对精度低，难以降低空间TSI测量不确定度，无法满足气候变化、辐射收支等应用领域研究迫切需求。本项目拟研究溯源至低温辐射计的真空共光路TSI定标方法，基于太阳光谱辐照度分布，设计真空共光路定标模型的全光谱范围校正方法，结合黑体腔吸收比和光阑衍射的光谱特性，研究多光谱定标校正与全谱段定标等效性；基于夫朗禾费衍射原理，研究光阑衍射效应修正的理论模型和实验检测方法，降低光阑衍射修正因子不确定度；建立基于激光扫描的太阳辐射模拟仿真模型，研究高斯光束叠加与太阳辐射等效性，设计以快速扫描振镜和准直镜头为核心的光学系统，实现功率稳定、空间均匀的太阳辐射模拟。研究工作将为实现0.03%不确定度的TSI定标提供技术储备，跨越式提升空间TSI测量精度。

The sun is the only external energy source of the earth. The long-term accurate monitoring of the space Total Solar Irradiance (TSI) can provide scientific basis for climate change prediction and environmental policy formulation. At present, the absolute accuracy of TSI calibration of solar radiation remote sensors in China is low. The uncertainty of space TSI measurement cannot be reduced. The urgent needs of climate change, radiation budget and other application fields cannot be met. The project will research on the TSI calibration method traced back to the cryogenic radiometer by the vacuum common light path. Based on solar spectral irradiance distribution, the full spectral range correcting method will be designed for the calibration model of vacuum common light path. The equivalence between multispectral calibration and full band calibration will be researched according to the spectral characteristics of blackbody cavity absorptance and aperture diffraction. Based on Fraunhofer diffraction principle, the theoretical model and experimental measurement method for correcting the aperture diffraction effect will be researched, and reducing the uncertainty of the correction factor of aperture diffraction. The laser scanning simulation model of solar radiation will be established. The equivalence between the superposition of Gaussian beams and solar radiation will be researched. The optical system based on fast scanning galvanometer and collimating lens will be designed for simulating the solar radiation with stable power and uniform space. The research work will provide technical reserves for the realization of TSI calibration with 0.03% uncertainty, and markedly improve the accuracy of space TSI measurement.