Why Some Cycle Slip Detection Methods do not Work for Smartphones: Investigation, Explanation and Solutions

Jiahuan Hu

Peer Reviewed

Abstract:	Smartphone precise positioning has attracted significant attention in the field of global navigation satellite system (GNSS) for nearly ten years. The introduction of carrier-phase measurements in data processing provides for improved positioning performance, but at the same time, possible cycle slips in phase measurements can also degrade solution accuracy. The crucial role of cycle slip detection in precise positioning motivated this paper, in which the Melbourne-Wübbena (MW) combination, the geometry-free (GF) combination, code-minus-phase (CMP), as well as the Doppler cycle slip detection methods are investigated, analyzed, and assessed. Due to the clock inconsistency issue in time-differenced carrier-phase (TDCP) and Doppler measurements for phones such as the Xiaomi Mi8 and Samsung S20, the conventional Doppler cycle slip detection method is not applicable. Furthermore, other methods such as MW, GF, and CMP are easily affected by the frequent loss of dual-frequency measurements and noisy measurements in smartphones. This paper proposed a novel optimized Doppler detection method which regards the test value as a mean shift model which follows normal distribution, with median constellation and frequency-specific test values the means of the Gaussian distribution. Results show that, the noisy pseudorange measurements result in the insensibility of MW and CMP methods for small cycle slips. The GF method can detect small cycle slip which is only one cycle; however, it needs dual-frequency measurements and does not work for cycle slips which are close to the ratio of the two used frequency’s wavelengths. Compared to conventional cycle slip detection methods, the proposed Doppler cycle slip detection method has the best performance, with all the simulated cycle slips settings vary from 1-67 cycles detected. The proposed method has the potential in improving the positioning performance, and possibly, benefit smartphone ambiguity resolution.
Published in:	Proceedings of the 37th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2024) September 16 - 20, 2024 Hilton Baltimore Inner Harbor Baltimore, Maryland
Pages:	2541 - 2554
Cite this article:	Hu, Jiahuan, "Why Some Cycle Slip Detection Methods do not Work for Smartphones: Investigation, Explanation and Solutions," Proceedings of the 37th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2024), Baltimore, Maryland, September 2024, pp. 2541-2554. https://doi.org/10.33012/2024.19883
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In