Dynamic GPS-based LEO orbit determination with 1 cm precision using the Bernese GNSS Software

• Published in: Advances in space research Vol. 67; no. 2; pp. 788 - 805
• Main Authors: Mao, Xinyuan, Arnold, Daniel, Girardin, Valère, Villiger, Arturo, Jäggi, Adrian
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.01.2021
• Subjects: Bernese GNSS software; Non-gravitational forces; Precise orbit determination; Sentinel satellites; Single-receiver ambiguity resolution; Bernese GNSS software; Sentinel satellites; Precise orbit determination; Non-gravitational forces; Single-receiver ambiguity resolution
• ISSN: 0273-1177; 1879-1948
• DOI: 10.1016/j.asr.2020.10.012

The Astronomical Institute of the University of Bern (AIUB) has been performing GPS-based Precise Orbit Determination (POD) for a large variety of Low Earth Orbit (LEO) satellites since two decades. Traditionally, LEO orbits have been generated by a reduced-dynamic POD strategy using the Bernese GNSS Software, replacing an explicit modeling of non-gravitational forces by dedicated empirical orbit parametrizations. This LEO POD strategy can be advanced by two main developments: on the one hand, use is made of the GNSS Observation-Specific Bias (OSB) and clock products provided by the Center for Orbit Determination in Europe (CODE), allowing for the resolution of single-receiver GNSS carrier-phase ambiguities. On the other hand, the main focus of this article, a refined satellite non-gravitational force modeling strategy is constructed to reduce the amount of empirical parameters used to compensate for force modeling deficiencies. LEO POD is first performed for Sentinel-3, a satellite formation currently consists of two identical satellites −3A and −3B, which experience a similar in-flight environment and allow for direct POD performance comparisons. A third satellite Swarm-C, which flies at a lower altitude and has a more sophisticated surface geometry, is selected to validate the robustness of the new POD strategy. As a result, both the internal consistency checks and external orbit validations suggest superior orbit quality obtained for the three satellites for a time span of 1.5 years (7 June, 2018 to 31 December, 2019). The ambiguity resolution adds strong constraints to the orbits and the satellite non-gravitational force modeling leads to more tightly constrained (towards zero) pseudo-stochastic empirical parameters. The final orbit solutions agree with external orbit solutions and independent satellite laser ranging measurements at levels of sub-cm, indicating approximately 20% improvement w.r.t. the nominal reduced-dynamic orbit solutions. This suggests potential benefits to the space geodesy community that always pursues best-possible satellite orbits.