针对定标光源和遥感器在轨探测目标的光谱非匹配对空间光学遥感器实验室辐射定标精度的影响, 设计了一种基于发光二极管(LED)和基底光源的光谱分布可调谐光源。采用该光源模拟了典型地物目标光谱, 用于遥感器的实验室绝对辐射定标, 大幅降低了光谱非匹配带来的影响。首先, 从理论上分析了光谱非匹配影响遥感器绝对辐射定标精度的机理; 然后, 根据设计指标确定了光源的设计方案, 解决了光源的选型与光谱匹配算法设计、光谱分布可调谐光源驱动和控制系统、目标光谱匹配与光谱反馈调整、光谱分布可调谐光源光机设计等四项关键技术问题; 最后, 对光源进行了性能测试。测试结果显示: 等能光谱和6 000 K黑体光谱的光谱匹配误差分别为6.37%和8.76%, 出光口的辐照度非均匀度为053%, 30 min内的辐照度不稳定度为0.03%, 水平方向±30°内的辐亮度角度非均匀度为0.80%, 各波长处光谱辐亮度值均高于0.07 W/(m2·sr·nm), 410~900 nm波段积分辐亮度为58.3 W/(m2·sr), 均满足设计指标。

A spectrum-tunable integrating sphere light source based on a Light Emitting diode(LED) and basis sources was developed to eliminate the effect of spectral non-matching between calibration source and an on-orbit detecting target on the calibration accuracy of space optical remote sensor in a laboratory. The developed source was used to produce typical ground object spectra and to calibrate space optical remote sensors, which significantly diminishes the absolute radiometric calibration error caused by spectral non-matching mentioned above. Firstly, the affecting mechanism of the spectral non-matching on the absolute radiometric calibration accuracy of space optical remote sensor was analyzed. Then, the design scheme of the spectrum-tunable light source was given according to technical requirements. The scheme was mainly divided into four key issues: the determination of light source and design of spectral matching algorithm, the design of light source drive circuit and control system, the matching of target spectrum and spectral adjustment, and the optical-mechanical design of spectrum-tunable light source. In the end, the performance of calibrated spectrum-tunable light source was tested. The results show that the spectral non-matching errors of equi-energy spectrum and 6 000 K blackbody spectrum are 6.37% and 8.76% respectively, the irradiance non-uniformity is 0.53%, the irradiance instability of the spectrum-tunable light source within 30 min is 0.03%, and the radiance angular non-uniformity of the spectrum-tunable light source within horizontally ±30° is 0.80%. Moreover, it offers the spectral radiance above 007 W/(m2·sr·nm) and the integral radiance in 410—900 nm of 58.3 W/(m2·sr). These data all meet the design requirements of spectrum-tunable light sources.