Multiple Satellite Cycle Slip Recovery for Smartphones Based on Parity Method Using Time-Differenced Carrier Phase (TDCP)

Ho Namgung, Jae Woong Hwang, Hojoon Jeong, Changdon Kee

Abstract:	When using smartphones for precise GNSS positioning, cycle slips in carrier-phase measurements frequently occur and can occur on several satellites simultaneously. Because smartphones use small, low-cost antennas, cycle slips occur more often than with commercial receivers, making centimeter-level navigation particularly challenging. In this paper, we propose a novel cycle slip recovery algorithm for single-frequency GNSS measurements that operates without additional sensors by combining Time-Differenced Carrier Phase (TDCP) measurements with the parity method. The key idea is a subspace-based approach that enables direct estimation of cycle slip magnitudes, together with a residual test and a repetition check to validate and reinforce the estimation. Correct estimations repeatedly occur across different subspaces, whereas wrong estimations do not, making reliable recovery possible. Monte Carlo simulations with 100,000 epochs demonstrated 100% recovery for cycle slips on one or two satellites, and recovery rates above 99.7% even when cycle slips occurred simultaneously on three or four satellites. The method was further validated in a real static smartphone experiment, confirming that the algorithm can maintain continuous positioning in the presence of actual cycle slips. These results suggest that the proposed method not only enables precise navigation on smartphones but also holds strong potential for extension to dynamic and real-time applications.
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:	1120 - 1131
Cite this article:	Namgung, Ho, Hwang, Jae Woong, Jeong, Hojoon, Kee, Changdon, "Multiple Satellite Cycle Slip Recovery for Smartphones Based on Parity Method 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. 1120-1131. https://doi.org/10.33012/2025.20477
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