可在轨溯源的太阳反射波段光学遥感仪器辐射定标基准传递链路

分析了现行光学遥感仪器辐射定标方法的局限性,以满足定量化遥感的精度及多数据融合比对研究的需求。设计了以空间低温辐射计为初级辐射基准,以太阳为光源,包括太阳单色仪、太阳光谱仪、传递辐射计、太阳漫反射板等组件在内的可在轨溯源的光学遥感仪器辐射定标基准传递链路。首先以低温辐射计和太阳光源建立的光谱辐射基准定标传递辐射计和太阳光谱仪;然后利用传递辐射计定标太阳漫反射板,建立对地光谱辐亮度基准;继而将基准传递至地球光谱成像仪作为对地观测标准,从而实现对其它卫星光学遥感器的交叉定标。对光学遥感仪器辐射定标基准传递链路各个环节的分析显示,辐射定标基准传递链路的测量相对不确定度为0.75%。结果表明,以此辐射基准传递链路构建覆盖我国空天一体的遥感定标网络可为建立平行于地面基准体系的空间数据质量保障体系奠定技术基础。

Standard transfer chain for radiometric calibration of optical sensing instruments with traceability in solar reflective bands

The weakness of current radiometric calibration methods for optical remote sensing instruments was analyzed to satisfy the precision needs of quantitative remote sensing and the data fusion coming from multi satellites. A standard transfer chain for radiometric calibration of optical sensing instruments with traceability was designed by taking a space cryogenic radiometer as a primary system for radiometric reference and the sun as the light source, which includes a solar monochromator, a transfer radiometer, a solar spectral irradiance monitor and a solar diffuser,etc. In radiometric calibration, the transfer radiometer and the solar spectral irradiance monitor were calibrated firstly by using spectral radiometric standards provided by the solar monochromator. And then the solar diffuser was calibrated by using the transfer radiometer. The radiometric standard was transferred to an imaging spectrometer for an earth observing standard, so that the radiometric standard could be used for inter calibration of other remote sensing instruments on other satellites. The analysis on the radiometric calibration for the standard transfer chain shows that the uncertainty of optical sensing instruments is 0.75%. It demonstrates that the proposed method is helpful for constructing calibration networks of remote sensing covering China in space and air and provides a technology foundation for developing space data quality assurance system parallel to the ground system of primary radiometric standards.