On the Integrity Assurance of Carrier-Phase PNT

Peter J.G. Teunissen, Chengyu Yin, and Christian C.J.M. Tiberius

Abstract:	GNSS monitoring and model validation constitute an important part of any GNSS data processing and integrity assuring scheme. Statistical tests are employed to test for the stability of estimated parameters, for instance, in GNSS time-series for displacement, deformation or landslide studies, or in case of integrity assurance, for the occurrence of model misspecifications, such as pseudo range outliers, carrier-phase slips, and neglected atmospheric delays. To achieve the highest accuracy in GNSS parameter estimation, carrier-phase measurements are used, as they have a two-orders of magnitude better precision than their pseudo range (code) counterparts. However, since the interferometric carrier-phase observables are integer ambiguous, the carrier-phase GNSS models are of the mixed-integer type, consisting of real-valued and integer-valued parameters. Although the theory for mixed-integer GNSS parameter estimation is reasonably well developed (Leick et al., 2015; Teunissen and Montenbruck, 2017; Morton et al., 2021), this is not yet the case for the integrity monitoring and validation of mixed-integer GNSS carrier-phase models. The absence of such is a hindrance for any safety-critical or liability-critical carrier-phase GNSS relying application. It is the goal of this contribution to demonstrate how the integerness of the carrier-phase ambiguities can be properly exploited for the purpose of significantly improving the power of the employed statistical integrity tests. By doing so, we show that integer ambiguity resolution has a dual-role to play, one for parameter estimation and one for model validation. The mixed -integer testing methodology presented is also not restricted to carrier-phase GNSS, but applies to any interferometric carrier-phase based PNT-system, including terrestrial and non-terrestrial carrier-phase signals of opportunity (Yang et al., 2025).
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:	2714 - 2720
Cite this article:	Teunissen, Peter J.G., Yin, Chengyu, Tiberius, Christian C.J.M., "On the Integrity Assurance of Carrier-Phase PNT," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 2714-2720. https://doi.org/10.33012/2025.20453
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