卫星遥感载荷在轨辐射定标需要高稳定、高可靠、可追溯的辐射定标源支持。将辐射基准搬至空间平台，利用同步对地观测的方式将基准传递至卫星载荷，已成为未来提升在轨辐射定标精度的可行方式之一。临近空间高度上可获得与卫星相接近的观测，同时，以高空科学气球为代表的临近空间浮空器还具有长时区域驻空、可回收等平台优势，也是空间辐射基准可选择的搭载平台之一。本文介绍了将高空科学气球作为平台搭载辐射参考载荷的系统设计，以及在青海大柴旦地区开展的临近空间光学载荷辐射定标飞行试验情况。结合试验获取的临空平台位置姿态数据、观测辐射亮度数据，分析了临近空间高空科学气球平台及辐亮度计的工作稳定性，给出了在临近空间开展卫星光学载荷定标的一般性方法，并对定标不确定度进行了分析，得到气球过境均匀区和山地区辐亮度观测的不确定度分别为3.8% ~ 4.3%和5.0% ~ 6.8%。与MODIS、GF-6\WFI同步观测数据比对结果也一定程度上证实了不确定度估算的可靠性。本次基于临近空间高空科学气球的卫星光学载荷辐射定标试验探索了高空科学气球作为空间辐射基准搭载平台的可行性，为进一步发展基于临近空间的辐射基准传递定标系统积累了经验。

The on-orbit calibration and performance monitoring of satellite remote sensing payload calls for the support of the radiometric calibration source, which is of high stability, high reliability and traceability. Facing the problem of the improving the accuracy of on-orbit radiometric calibration, one of the most effective ways is to move the radiometric benchmark from laboratory to space-borne platform, to from “calibration satellites”, just like “THUTHS”, “CLARREO” and Chinese “LIBRA”. And then the simultaneous nadir overpass observations obtained from both the calibration satellite and other satellites can be employed to transfer the benchmark to other satellites. However, up to now all the above projects are in the research and development stage. There is currently no operational satellites that can be used to validate the benchmark transfer chain, which is one of the core functions of the future calibration satellites. Taking into account that the high-altitude scientific balloon has the advantages of close to the TOA observations, long-term regional flight and recyclability, it can be regarded as an optional platform for space radiometric benchmarks. This paper illustrated the composition of the demonstration system, which could be working in near-space altitude, with high-altitude scientific balloon as a platform, and a radiometer covering the spectrum range of 400-2500nm as the main Earth observation instrument. In this paper, the flight experiment utilizing this system in Da-Qaidam in Qinghai Province was also introduced. During this flight, the position and attitude data of the balloon platform and the observed radiance data were obtained and fully recorded. These data were firstly used to analyze the stability of the high-altitude scientific balloon platform and the radiometer in the near-space. The result revealed that during the whole flight the radiometer was in a stable environment and working well. And then, a general method of satellite radiometric calibration with the balloon observation in the near-space was given, within the consideration of balloon flight track that are difficult to fully control. The uncertainty of the proposed method could be reached to 3.15% ~ 3.35% and 4.60% ~ 4.75%, respectively, in the uniform and mountain area. At last, the comparison with MODIS and GF-6\WFI synchronous observations were used to confirmed the reliability of uncertainty analysis. The satellite and the balloon observations had good agreement with each other. The successful of the flight experiment explored the feasibility of high-altitude scientific balloons as a space radiometric benchmark carrying platform. And it also accumulated experience for the further development of a near-space-borne radiometric benchmark transfer calibration system.