Enhanced geopotential field modelling as basis for the establishment of precise height systems (Geo-H)

目前大地测量学的一个挑战是实施一个综合的全球大地测量参考框架(GGRF)，该框架支持按照国际大地测量协会(IAG)的定义和2015年联合国关于全球大地测量参考框架促进可持续发展的决议的规定，在全球范围内以高精度一致地确定和监测地球的几何、自转和重力场变化。GEO-H项目的主要目标是按照全球国际高度参考系统(IHRS)的定义，为实现现代基于地球位势的高度系统奠定方法学基础，这是迈向全球地球观测框架的主要要求。我们的目标是：(1)以高分辨率重力场和区域大地水准面建模方面的专业知识为基础，(1)高可靠地量化物理高程测定的误差预算；(2)发展新的概念和方法，以改进的地球位势解决方案及其精度评估为基础；(3)为实现全球一致的重力场和区域大地水准面系统提供科学指南和路线图。该项目建立在三个基石上：(1)通过与独立观测进行比较，对区域地球位势(大地水准面)模型进行误差预算分析，并查明/减少与不同大地水准面建模方法有关的系统误差。(2)改进随机模型，对不同分辨率的重力数据进行谱组合和最优加权，以实现重力(大地水准面)模型确定中严格的误差传播分析。(3)编制建立、维持和长期维持基于地球位势的高度系统的科学概念，重点是建立全球IHRS。Geo-H的方法、发展和结果将被放在国际上作为基线方法，作为实现IHRS的科学和管理指南，更广泛地说，用于实现基于地球位势的高度系统。

A current challenge of Geodesy is the implementation of an integrated Global Geodetic Reference Frame (GGRF) that supports the coherent determination and monitoring of the Earth’s geometry, rotation, and gravity field changes with high accuracy worldwide as defined by the International Association of Geodesy (IAG) and declared by the United Nations Resolution on a GGRF for Sustainable Development in 2015. The main objective of the project Geo-H is to develop the methodological foundation for the realization of modern geopotential-based height systems in agreement with the definitions of a global International Height Reference System (IHRS) as a main requirement to advance towards the GGRF. Based on the expertise of the “Ingenieurinstitut für Astronomische und Physikalische Geodäsie” (IAPG) and the “Deutsches Geodätisches Forschungsinstitut der Technischen Universität München” (DGFI-TUM) on high-resolution gravity field and regional geoid modelling, we aim at (1) quantifying with high reliability the error budget of the physical height determination,(2) developing new concepts and methods towards improved geopotential solutions and their accuracy assessment, and (3) providing scientific guidelines and a roadmap for the realization of globally consistent geopotential-based height systems. The project is built on three cornerstones: (1) Error budget analysis from the validation of regional geopotential (geoid) models by means of comparison to independent observations and the identification/reduction of systematic errors associated to different geoid modelling methods. (2) Improvement of stochastic models, spectral combination and optimal weighting of gravity data of different resolutions to implement rigorous error propagation analyses in the determination of geopotential (geoid) models. (3) Compilation of a scientific concept for the establishment, maintenance, and long-term sustainability of geopotential-based height systems, with emphasis in the establishment of the global IHRS. Methodologies, developments and findings of Geo-H will be placed on international level as baseline methods, to be used as guidelines for science and administration in the realization of the IHRS, and more general, in the realization of geopotential-based height systems.