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

• Applicant: Professor Dr.-Ing. Harald Schuh
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 532942504

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.

• DFG Programme: Research Grants
• Co-Investigators: Professor Dr.-Ing. Maorong Ge; Professor Dr. Urs Hugentobler