Multi-constellation and multi-sensor integrated non-conservative forces modeling framework (MOTIVATING)

全球导航卫星系统（GNSS）所有实时服务和与GNSS相关的科学研究的一个重要前提是卫星轨道的准确性。作用在卫星上的非保守力的错误建模是轨道精度下降的主要原因之一，因此日食季节的非保守力建模仍然是一个关键的挑战。由于卫星在日食季节处于阴影区，没有直接的太阳辐射压（SRP）效应作用于它，其他潜在的非保守摄动力往往是显着的。对于特定的卫星来说，穿过一个阴影区域的持续时间大约是几个小时或更短，并且具有如此稀疏的时间间隔的传统的仅GNSS轨道解无法精确地捕获显著的非保守摄动力的同时变化。各种先进的卫星导航和大地测量技术的快速发展，如全球导航卫星系统启用的低地球轨道（LEO）卫星星座的部署与测距链接到更高轨道的卫星，从地面的卫星激光测距（SLR）链接，和星间链路（ISL）有效载荷提供了一个有前途的潜力，高分辨率的非保守力建模。本项目将在观测层开展GNSS/LEO/SLR/ISL紧密集成处理模型的研究，以提高对非保守力短期同时变化的探测能力。该项目的主要科学目标是研究和建立一个新的，严格的，全面的建模框架，基于多星座和多传感器集成处理将重要的非保守力模型与特定卫星联系起来。我们的研究旨在填补这一领域的研究空白，并为力模型的物理解释提供新的见解。·将研究GNSS/LEO/SLR/ISL综合处理的数学模型，以形成高分辨率非保守力建模的基础。研究了观测水平上的质量控制和权重策略。·在高分辨率非保守力建模中，将基于所有可用的多星座元数据来执行力模型参数的长期系统偏差的估计。此外，空间和时间特性的重要力量模型参数将进行分析，新检测到的随机特性的重要非保守力将允许更准确的物理解释。·本项目中产生的新的非保守力模型将被分类，以建立多星座的综合建模框架。将进一步评估应用新的建模框架对GNSS相关科学研究的潜在改进。

An important prerequisite for all the real-time global navigation satellite systems (GNSS) services and GNSS-related scientific researches is the accuracy of satellite orbits. The mismodeling of non-conservative forces acting on the satellites is one of the major reasons for degradation in orbit accuracy and thus the non-conservative force modeling over eclipse seasons remains a key challenge. As the satellite is within the shadow area over eclipse seasons, no direct solar radiation pressure (SRP) effects act on it and the other potential non-conservative perturbing forces tend to be significant. The duration of crossing one shadow area is about a few hours or less for a specific satellite and the simultaneous variation of significant non-conservative perturbing forces cannot be precisely captured by the traditional GNSS-only orbit solution with such a sparse time interval. The rapid development of various advanced technologies for satellite navigation and geodesy, like the deployments of GNSS enabled low earth orbit (LEO) satellite constellations with ranging links to satellites in higher orbits, satellite laser ranging (SLR) links from ground, and inter-satellite link (ISL) payloads offers a promising potential for the high-resolution non-conservative force modeling. In this project, we will carry out research on a GNSS/LEO/SLR/ISL tightly integrated processing model on the observation level for enhancing the capability of detecting the short-term simultaneous variation of non-conservative forces. The main scientific objective for the project is to investigate and establish a new, rigorous, and comprehensive modeling framework that links significant non-conservative force models to a specific satellite based on the multi-constellation and multi-sensor integrated processing. Our study aims to fill the research gap in this field and provides new insights into the physical interpretation of force modeling. The following key aspects will be addressed in this project: • A mathematical model for GNSS/LEO/SLR/ISL integrated processing will be investigated to form the basis for the high-resolution non-conservative force modeling. The quality control and weight strategies on the observation level will be investigated. • In the high-resolution non-conservative force modeling, estimation of long-term systematic biases of force model parameters will be performed based on all available multi-constellation metadata. Moreover, spatial and temporal characteristics of significant force model parameters will be analyzed and newly detected stochastic characteristics of significant non-conservative forces will allow more accurate physical interpretations. • New non-conservative force models produced within this project will be categorized to establish a comprehensive modeling framework for multi-constellations. The potential improvements in the GNSS-related scientific researches due to applying the new modeling framework will be further evaluated.