陆地观测卫星遥感产品真实性检验场网建设的思考与实践

Practice and reflection on the construction of remote sensing products validation network for the land observation satellite

遥感产品真实性检验作为衔接遥感数据产品与应用服务的重要过程,是遥感数据产品高质量应用的必要保证。多年来,国内外建设了不少面向陆地遥感产品的真实性检验站点,但由于陆表过程和观测目标的高度复杂性、遥感卫星载荷产品的多样性、陆地遥感产品演变的动态性,在典型特性表征—要素测量—样本优化—弹性服务全过程中的理论运用与技术实现仍显不足,规模化基础设施有待进一步发挥可持续运行的服务价值。本文分析了真实性检验地面观测场网、地面参考真值获取技术、遥感产品综合检验服务的国内外现状与发展趋势,进而从理论方法体系化着手,提出在地统计学的空间变异理论、计量学的不确定性理论、运筹学的最优化理论等基础之上,研究真实性检验场网空间代表性表征、测量基准不确定性度量及传递、多途径检验结果综合定权合成、样本集与待检产品的最优匹配等方法,发展形成陆地观测卫星真实性检验场网方法体系框架。对标国家空间基础设施重大工程建设和关键共性产品的应用需求,综合考虑整体布局、产品覆盖完备性、时空基准一致性和可追溯性等因素,统筹建设完善真实性检验站网、航空协同真实性检验系统、基准参考构建及传递系统以及高精度检验服务系统,形成符合中国实际的陆地观测卫星遥感产品真实性检验技术方案。文章对于完善真实性检验场网理论方法体系,“用足”、“用好”国产陆地观测卫星遥感数据,提升定量化应用水平具有重要意义。

Validation of remote sensing products,as a crucial process bridging remote sensing data products and their application services,is essential for meeting the increasing demands for precision and performance in a series of quantitative applications.Such a validation is also necessary for improving the algorithm and production procedure after collecting feedback in such applications.Over the years,numerous sites for the validation of land remote sensing products have been established domestically and internationally.However,the theoretical and technical systems in the construction of a validation network is still not perfect in the entire process.These systems include the site characteristic representation and selection,measurement of surface and/or atmospheric parameters,sampling of measurement,and validation service mode toward different users.The possible reasons include the complexity and dynamic nature of the Earth system that lead the interaction between different spheres,land surface heterogeneities and uniformities,system and random errors in measurements,and various types of remote sensing satellite products for different applications.These problems result in difficulties in fully utilizing existing facilities.Therefore,to solve a series of basic theories and techniques problems,and to provide new models and specific solutions become the precondition in improving the application efficiency of validation system infrastructure at present and in the near future.In this research context,the status and development trends are first analyzed,including the research domain of ground observation networks for validation,acquisition technology for ground reference truth,and comprehensive validation services for remote sensing products domestically and internationally.Thereafter,three basis theories(i.e.,spatial variability theory in geostatistics,uncertainty theory in metrology,and optimization theory in operations research)are adopted to improve the validation methods.These three theories explore the spatial representativeness characterization of the network of product validation,uncertainty analysis and transfer of the fiducial reference measurements,comprehensive weighting and composition of multiple validation results,and optimal balance between the validation resources and user demands.Based on the theories,a framework is developed for the methodological system of the terrestrial observation satellite product validation network.This framework lays the theoretical foundation for the construction of a remote sensing production validation system and plays an important supporting role in forming targeted solutions.Aiming with the construction of the National Civil Space Infrastructure and the application needs of validation of key common products,considering overall layout,product coverage completeness,spatio-temporal consistency,and traceability,this study proposes specific requirements for the validation targets,validation areas,validation methods,validation accuracy,validation frequency,and service mode of Chinese land observation satellite remote sensing product validation network.The blueprint of the validation network for the“14th Five Year Plan”was designed based on the proposed methodology.This study coordinates the construction of a comprehensive product validation network,comprising an aerial collaborative validation system,a benchmark referenced transfer and fiducial reference measurement system,and a high accuracy validation service system.This network forms a technical solution for Chinese land observation satellite remote sensing product validation.The proposed solution will promote the resolution of related bottleneck issues,such as the accuracy,efficiency,and consistency of product validation.Lastly,the proposed solution will significantly improve the theoretical method system of the product validation network by fully utilizing and optimizing the use of domestic land observation satellite remote sensing data,and enhancing the level of quantitative applications.