Cycle Slip Detection and Recovery for Integrity Monitoring in Deep Urban Environments Using Time Differenced Carrier Phase (TDCP)

Hojoon Jeong, Changdon Kee, Junesol Song

Abstract:	In this study, we applied a TDCP-RAIM–based integrity monitoring technique to data obtained from vehicle experiments in urban environments and demonstrated that the required integrity requirements were met. This method does not require a cycle ambiguity resolution because it uses Time Differenced measurements to obtain a relative position and to conduct the integrity monitoring. A conventional RAIM technique that uses TDCP measurements already exists, known as Relative Receiver Autonomous Integrity Monitoring (RRAIM). RRAIM performs differencing between the current epoch and a fixed initial epoch measurement. Due to its differencing scheme, RRAIM becomes less efficient in dynamic environments where the number of visible satellites changes. In contrast, TDCP-RAIM enables the use of newly available satellites and continuous positioning even under rapidly changing satellite visibility, which is a limitation of conventional methods. Since handling cycle slips is essential for the practical use of carrier-phase measurements, TDCP-RAIM has the advantage that its short differencing interval makes cycle-slip detection highly feasible, even with low-cost inertial sensors. In order to confirm the performance of the proposed method, we conducted a real vehicle-based experiment in an urban area. Under the assumption that the initial position is provided by SBAS, the results demonstrate that TDCPRAIM maintains SBAS-level performance in urban environments and satisfies the integrity requirements, which cannot be achieved by RRAIM.
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:	1893 - 1906
Cite this article:	Jeong, Hojoon, Kee, Changdon, Song, Junesol, "Cycle Slip Detection and Recovery for Integrity Monitoring in Deep Urban Environments Using Time Differenced Carrier Phase (TDCP)," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 1893-1906. https://doi.org/10.33012/2025.20478
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