海域航空重力向下延拓非求逆稳健算法研究

High precision marine gravity observation information is the essential basic data for the geoid refined and the unification of the global height datum, also is the key elements for the aerospace aircraft determination orbit precisely, the strategic missile precision guidance and the underwater vehicle navigation. The air gravity measurement in sea area is an important means to detect the information of the ocean gravity field, and is also a hot spot in the field of ocean surveying and mapping. Downward continuation is one of the essential links to translate the airborne gravimetric achievements to the application area. Due to the downward continuation of airborne gravity data based on the idea of inversion is difficult to meet the engineering application requirements. This project base on the inherent ill posed problem in the airborne gravity downward continuation, analyzing the coupling relationship between the downward continuation elements, and revealing the error amplification mechanism in the downward continuation process. From the following three aspects: the multi-source characteristics of the sea gravity information, the frequency spectrum of the airborne gravity signal, and the boundary correlation between the upward and downward continuation of the potential field, three kinds of non inverse robust downward continuation models, which are differential correction number method, spectrum band limited method and least squares analytical method based on upward continuation, are constructed respectively. The applicability and effectiveness of the above robust downward continuation model in different sea areas are evaluated with different characteristics will be verified by theoretical derivation, simulation analysis and test verification, thus to provide practical and reliable airborne gravity downward continuation method for engineering applications, and also providing technical support for the construct and also providing technical support for the construction of a perfect marine airborne gravity measurement system.

高精度海洋重力观测信息是精化海域大地水准面，实现全球高程基准统一的基础资料。海域航空重力测量是探测海洋重力信息的重要手段，向下延拓是海域航空重力测量成果向应用领域转化的关键环节之一，当前基于求逆思路的海域航空重力向下延拓技术难以满足工程化的应用需求。本项目拟针对海域航空重力向下延拓在数学上固有的不适定问题，分析向下延拓要素之间的耦合关系，揭示向下延拓过程中的误差放大机理；从海域重力信息的多源特性、海域航空重力测量信号的频谱构成以及位场向上与向下延拓的边值关联等角度出发，分别构建差分改正数法、频谱带限法和基于向上延拓的最小二乘解析法等相对应的非求逆稳健向下延拓模型；采用理论推导、仿真分析和试验验证相结合的手段，评估上述稳健向下延拓新模型对不同海域航空重力测量特征的适用性和有效性，为海域航空重力向下延拓工程化应用提供理论依据，为构建完善的海域航空重力测量作业体系提供技术支撑。

高精度海洋重力观测信息是研究确定海域地质构造和矿产资源分布规律、查明地质体储存状态必不可少的基础资料，同时也是精化海域大地水准面，实现全球高程基准统一必不可少的基础资料。海域航空重力测量是探测海洋重力信息的重要手段，向下延拓是海域航空重力测量成果向应用领域转化的关键环节之一，基于求逆思路的海域航空重力向下延拓技术难以满足工程化的应用需求。本项目针对海域航空重力向下延拓在数学上固有的不适定问题，分析向下延拓要素之间的耦合关系，揭示向下延拓过程中的误差放大机理；从海域重力信息的多源特性、海域航空重力测量信号的频谱构成以及位场向上与向下延拓的边值关联等角度出发，分别构建了差分改正数法、频谱带限法和基于向上延拓的最小二乘解析法等相对应的非求逆稳健向下延拓模型；采用理论推导、仿真分析和试验验证相结合的手段，评估上述稳健向下延拓新模型对不同海域航空重力测量特征的适用性和有效性。项目研究过程中发表学术论文14篇，其中SCI收录4篇，EI收录2篇，中文核心收录8篇；公开发行专著1部，由科学出版社；授权发明专利5项，资助培养博士研究生2名，完成了全部预期的内容研究，达到了预期目标。项目成果为工程化应用提供了实用可靠的海域航空重力向下延拓计算方案，为构建完善的海域航空重力测量作业体系提供了技术支撑。