Lunar Surface Station to Support Lunar Positioning, Navigation, and Timing Services

Guillem Casadesus Vila and Grace Gao

Abstract:	Lunar Positioning, Navigation, and Timing (PNT) services are critical for upcoming crewed and robotic missions, many of which will rely on the availability of these services during the early deployment phases of LunaNet Service Provider (LNSP) constellations. Considering different stages of an LNSP constellation with two and five satellites in Elliptical Lunar Frozen Orbits (ELFOs), this work investigates the benefits in orbit determination and time synchronization (ODTS) of deploying a lunar surface station. We evaluate the performance of various measurement combinations, including weak GNSS signals, inter-satellite links (ISLs), and satellite-to-surface links, under different clock configurations for both the satellites and the surface station. Results demonstrate that combining weak signals from Global Navigation Satellite Systems (GNSS) with a surface station improves ODTS accuracy by an order of magnitude, providing a superior alternative to ISLs. We also show that a high-stability clock on the surface can compensate for lower-grade satellite clocks, with the combined architecture achieving meter-level accuracy and satisfying LunaNet performance requirements. These findings highlight the potential of hybrid orbital-surface architectures to enhance the availability of lunar navigation services and improve the capabilities of future missions.
Published in:	Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025) September 8 - 12, 2025 Hilton Baltimore Inner Harbor Baltimore, Maryland
Pages:	2861 - 2877
Cite this article:	Vila, Guillem Casadesus, Gao, Grace, "Lunar Surface Station to Support Lunar Positioning, Navigation, and Timing Services," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 2861-2877. https://doi.org/10.33012/2025.20258
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