Abstract: | This paper presents a comprehensive analysis of the potential error sources in Low Earth Orbit (LEO)-based Positioning, Navigation, and Timing (PNT) and their impact on positioning accuracy. Signals emitted by the LEO satellite constellations are prone to several sources of disturbances. Error sources such as inaccuracies in satellite orbital information, limited clock stability and atmospheric and multipath effects are considered. Accounting for these errors is crucial for improving the accuracy of LEO-based positioning. Popular positioning approaches, including Doppler shift and pseudo-range, are explored, and the ways in which different error sources affect their accuracy is investigated. The objective of this work is to facilitate a better understanding of the impact of various signal errors on the performance of the positioning approaches. The paper provides insights into how disturbances to the received signal impact positioning accuracy by deriving the Fisher Information Matrix (FIM) for each of the positioning approaches achieved under three realistic LEO-based positioning scenarios, which represent a open sky, residential and urban canyon environment. In the scenarios, the Starlink constellation was considered, which provides full global coverage using thousands of deployed satellites. The impact of the error sources has been augmented into the FIM and has been evaluated using simulations with various measurement strategies. By considering measurements of only the Doppler shift, only pseudo-range, or both, it has been shown that error on the satellite’s orbital information and the number of satellites in line of sight have a significant effect on the achievable positioning accuracy. Moreover, it has been shown that ionospheric delay effects has the most impact on pseudo-range based methods, while the delay rate only affects the Doppler shift based methods. |
Published in: |
Proceedings of the 37th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2024) September 16 - 20, 2024 Hilton Baltimore Inner Harbor Baltimore, Maryland |
Pages: | 2272 - 2286 |
Cite this article: | Sardarabadi, Ahmad Mouri, Knaap, Vincent van der, Rodriguez, Eva Fernandez, Bosma, Detmer A., Hildmann, Hanno, "A Systematic Approach to LEO-Based PNT Error Source and Performance Analysis," Proceedings of the 37th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2024), Baltimore, Maryland, September 2024, pp. 2272-2286. https://doi.org/10.33012/2024.19730 |
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