High-Integrity Surface Navigation for Unmanned Aircraft: A Multi-Frequency GNSS Approach

Daniel J. Larimer, Samer Khanafseh, Kana Nagai, and Boris Pervan

Abstract:	The aviation landscape is undergoing a rapid shift as advanced automation transforms not only unmanned aircraft, but also conventional platforms enhanced with pilot-assist or semi-autonomous functions. Despite decades of research and development, there is currently no safety-assured system capable of performing automatic takeoff, landing, and taxiing. In the past two decades, automatic approach and landing have seen significant technological development, while limited research and development in surface operations has left a critical void in technological readiness for UAS integration. This study proposes a navigation system architecture capable of filling the technical gap in autonomous aircraft surface operations. The analysis begins by identifying the scope of operations and the stringent accuracy requirements that the system will be expected to meet. Regulatory authorities are proactively shaping standards for autonomous surface operations, and meeting these evolving benchmarks is essential for the operations of any automated or assisted aircraft. In this work, we present a multi-frequency, multi-constellation differential GNSS architecture for automated and semi-autonomous aircraft surface operations, focusing on stringent integrity, continuity, and accuracy requirements. This approach builds on Ground-Based Augmentation System Approach Service Type E (GAST-E) inspired concepts to address this critical gap preventing seamless integration of Unmanned Aircraft System into the National Airspace System. We demonstrated through use of covariance analyses that even with significant satellite blockages from airport infrastructure, the system is capable of meeting the given requirements under fault-free conditions. Sensitivity analysis demonstrates that the system performance is highly impacted by the multipath environment, satellite blockage, and implementation of a zero-velocity update.
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:	311 - 332
Cite this article:	Larimer, Daniel J., Khanafseh, Samer, Nagai, Kana, Pervan, Boris, "High-Integrity Surface Navigation for Unmanned Aircraft: A Multi-Frequency GNSS Approach," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 311-332. https://doi.org/10.33012/2025.20305
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