Simulation of the Impact of Low-Earth-Orbit GNSS on Carrier Phase Ambiguity Resolution

Claire Mah and Kyle O’Keefe

Peer Reviewed

Abstract:	This paper details the impact that a Low-Earth-Orbit (LEO) constellation will have on existing GNSS carrier phase ambiguity resolution. A LEO constellation was modelled to have 66 satellites at an altitude of 780km and was used together with GPS satellites to conduct a global covariance simulation and evaluate the performance of a combined low- and medium-earth orbit system compared to GPS alone. The LEO satellites were found to improve how quickly the system could reach 99.9% probability of correct fix by a factor of 2.4 on average. Additionally, a detailed look at an example where a LEO satellite disappears early in the dataset emphasizes how strongly the system can be affected by the fast-changing geometry of a single LEO satellite. Overall, this leads to the conclusion that current GNSS systems will be well complimented by future LEO GNSS, and that LEO satellites will be beneficial to positioning applications without requiring full global coverage with redundancy. Keywords—LEO, low-earth-orbit, GNSS, ambiguity resolution, positioning, covariance
Published in:	2025 IEEE/ION Position, Location and Navigation Symposium (PLANS) April 28 - 1, 2025 Salt Lake Marriott Downtown at City Creek Salt Lake City, UT
Pages:	697 - 703
Cite this article:	Mah, Claire, O’Keefe, Kyle, "Simulation of the Impact of Low-Earth-Orbit GNSS on Carrier Phase Ambiguity Resolution," 2025 IEEE/ION Position, Location and Navigation Symposium (PLANS), Salt Lake City, UT, April 2025, pp. 697-703.
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