Precise Relative Positioning in MEO to Support Science Missions

Ramin Moradi, Maria Manzano Jurado, Jaime Fernández Sánchez, Manuel Martín-Neira

Peer Reviewed

Abstract:	Establishing inter-satellite baselines accurately in Medium Earth Orbit (MEO) would open the door to new missions in the areas of Science, Lunar Exploration and Earth Observation. Imaging of the event horizon of the supermassive black hole in the centre of our galaxy is an example. However, reaching the desired baseline positioning accuracy for such applications is challenging. The study case presented in this paper consists of a constellation of two radio telescope satellites, sharing the same polar MEO orbital plane and flying at 8280 km and 8303 km altitudes above the Earth surface, designed for imaging black hole shadows. The main objective of this study is to propose a relative positioning system that can determine the relative position vector between the two MEO satellites within 3 cm (3-sigma) on-the-fly and 3 mm (3-sigma) in postprocessing in each of the 3 relative coordinates x, y and z. The real time results presented in this report shows that at the first few days in which the baseline was relatively short, the required relative navigation performance is achieved (3cm 3sigma). However, with increasing the baseline the error reached to 20cm. The post-processing algorithm shows different results depending on the error budget assumed. Considering no geopotential errors, the accuracy in the direction of the black holes (the most interested direction) is bounded at 7 mm.
Published in:	Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022) September 19 - 23, 2022 Hyatt Regency Denver Denver, Colorado
Pages:	3632 - 3645
Cite this article:	Moradi, Ramin, Jurado, Maria Manzano, Sánchez, Jaime Fernández, Martín-Neira, Manuel, "Precise Relative Positioning in MEO to Support Science Missions," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 3632-3645. https://doi.org/10.33012/2022.18479
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