Real-Time Cycle Slip Detection and Isolation for Actual Smartphone Data Using the TDCP-Parity Method

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

Abstract:	Precise navigation on smartphones is consistently challenged by the frequent occurrence of cycle slips, primarily due to the limitations of low-cost antennas. Unlike commercial receivers, smartphones exhibit various types of cycle slip, including step, fluctuation, and ramp types, which lead to persistent positioning errors. This study proposes a real-time cycle slip detection and isolation method using only single-frequency carrier phase data without additional sensors. The proposed approach applies the Time-Differenced Carrier Phase (TDCP) and the parity method—a RAIM-based technique— to eliminate user motion and separate the cycle slip components. To overcome the detection limits of single-epoch analysis for non-step slips (ramps and fluctuations), which may remain undetected due to their small magnitude per epoch, we introduce a Multi-epoch TDCP residual test. This method evaluates test statistics over multiple time intervals, ensuring that even small, gradual changes in carrier phase are captured. Once a slip is detected, a subset residual test is employed to identify and exclude the specific satellite experiencing the slip. Furthermore, a position update strategy is applied to adaptively select the reference epoch, preventing bias errors that may occur when the small initial changes of a non-step slip are not immediately detected The effectiveness of the proposed method was verified through dynamic experiments using a Samsung Galaxy S22+. Results demonstrate that the multi-epoch approach successfully detects and isolates various types of slips, significantly improving the positioning accuracy and reliability of smartphone-based GNSS navigation.
Published in:	Proceedings of the ION 2026 Pacific PNT Meeting April 13 - 16, 2026 Hilton Waikiki Beach Honolulu, Hawaii
Pages:	318 - 330
Cite this article:	Namgung, Ho, Hwang, Jae Woong, Jeong, Hojoon, Kee, Changdon, "Real-Time Cycle Slip Detection and Isolation for Actual Smartphone Data Using the TDCP-Parity Method," Proceedings of the ION 2026 Pacific PNT Meeting, Honolulu, Hawaii, April 2026, pp. 318-330. https://doi.org/10.33012/2026.20588
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