多种多源数据混叠的局部重力场逼近理论与方法

Currently, the common algorithm based linear theory and methodology in gravity field approximation are mainly developed during 1970s～1980s. Over the past thirty years, with the rapid development of gravity observation technology, the traditional ground based acquisition of gravity field information has been evolving to airborne and spaceborne mode, which results in multi-type and multi-source complicated gravity data. The traditional theory and methods are difficult to deal with multi-type and multi-source complicated data for the refinement of high precision gravity field and geoid. This research mainly focus on the theory and algorithm for gravity field approximation, inculding precise terrain effect computation of the arbitary field element, high precision gravity field error analysis, stable estimation of the field element based on multi-source data, funsion of the multi-source complicated gravity field information and solution of the non-linear boundary value problem. By experimenting and analysis, the integrated theory and method of high precision gravity field approximation will be established, the capability of the algorithm system will be fully tested and the software system of local gravity field and geoid computation will be perfected. This research can provide theoretical and technical basis for the future centimeter level geoid determination, the modernization of height datum and the reasonable application of gravity field resources.

近30年来，重力场探测技术取得了突飞猛进的发展，信息获取方式已从地球表面全面拓展到海域及航空和卫星高度，数据资源不断丰富，但与之相适应的局部重力场逼近理论和算法研究严重滞后，难以满足当前复杂数据情况下高精度重力场及大地水准面精化的需要。本项目针对多种多源数据混叠情况下局部重力场逼近这一国际性难题，重点研究地球外空间任意类型重力场元的精密地形影响、高精度重力场误差理论、多源数据综合的场元稳定性估计、重力场整体集成融合以及非线性边值问题直接解法等基础理论和算法问题,在此基础上通过技术集成，构建较为完备的、统计框架下的高精度重力场逼近算法体系，全面测试验证算法体系的各项性能、指标及总体效果，完善局部重力场及大地水准面计算平台，以适应当前和今后厘米（毫米）级大地水准面精化的要求，为推进重力场资源科学合理应用和高程基准现代化奠定基础。

针对多种多源数据混叠情况下局部重力场逼近这一国际性难题，重点研究地球外空间任意类型重力场元的精密地形影响、高精度重力场误差理论、多源数据综合的场元稳定性估计、重力场整体集成融合以及非线性边值问题直接解法等基础理论和算法问题。提出了“地形影响移去-恢复法”的理论、方法和快速算法，发展了高精度重力场误差理论，发展了多源重力数据处理理论、方法与实用性较强的系列算法，提出了以边界面类型为标准的重力场边值问题。基于本项目的理论和算法研究进展，进一步完善了局部重力场及大地水准面计算平台，能灵活处理不同来源的地球重力场数据；重力场计算不再局限在地面或大地水准面，可以是地球外空间任意高度；场元类型不再局限于重力异常，可以是具有调和性质的任何类型实际地球扰动重力场元、多尺度分量、地形影响、地球部分质量生成的重力场元。综合利用沿海陆地、航空、船载和卫星测高海洋重力数据，精化陆海统一的局部重力场，计算与陆地一致的我国海域重力似大地水准面模型，精度达到3.9厘米。