Evaluating Performance of Meta-Signal Exploitation in End User

Carlos Moriana, Guillermo Ortas, Esteban Garbin, Elisa Benedetti, Nicholas Boreham, Pedro Boto, Javier Míguez, José Antonio García-Molina, Floor Melman

Abstract:	Satellite navigation has become an essential part of modern life, enabling us to know our position with unprecedented accuracy, ubiquity, and performance levels. As our reliance on satellite navigation continues to grow, the need for positioning accuracy and availability also increases, defining new use cases that demand them, like unmanned vehicles or autonomous driving. The natural step to achieve these goals is the exploitation of carrier phase observations in user receivers. However, despite the high accuracy level that such measurements can provide, their availability is more limited than code-based ones, mainly because of carrier ambiguity and cycle slip occurrence. Even if robust carrier techniques are explored in literature, this may not be enough for some scenarios like urban environments, where signal obstruction due to buildings is frequent. To address this gap, the meta-signal concept has been explored in recent years by the GNSS community as an alternative mechanism to provide very precise code measurements, also with high multipath rejection capabilities. This is achieved by an AltBOC-like processing of different signal components [1], where a subcarrier component is tracked to maximize the Gabor bandwidth of the composite power spectral density. It is this subcarrier the one contributing to this accuracy and can be understood as a wide lane combination of the underlying carrier-phase in each signal component. Even if not as accurate as the carrier-phase observable, meta-signal observables have geometric meaning, just as pseudoranges, and provides more relaxed tracking boundaries in terms of C/N0. Although relevant results have been provided for the meta-signal concept in theoretical simulations and controlled environments [2], the suitability of meta-signal measurements in real scenarios remains relatively unexplored. Evaluating their performances is one of the objectives of the HARSHTAG activity, which aims to translate the good tracking properties of meta-signals into enhanced end user accuracy. For this to be accomplished, calibration techniques are needed to remove all the non-geometrical effects that contribute to the positioning error budget and to define weighting schemes that allow to score each ranging measurement in the solution. Finally, specific techniques for unambiguous positioning estimation are discussed to avoid false locks affecting meta-signal measurements [3]. This will be extended in the future to a GNSS MIMO framework, by including multi-antenna exploitation.
Published in:	Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023) September 11 - 15, 2023 Hyatt Regency Denver Denver, Colorado
Pages:	340 - 354
Cite this article:	Moriana, Carlos, Ortas, Guillermo, Garbin, Esteban, Benedetti, Elisa, Boreham, Nicholas, Boto, Pedro, Míguez, Javier, García-Molina, José Antonio, Melman, Floor, "Evaluating Performance of Meta-Signal Exploitation in End User," Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023), Denver, Colorado, September 2023, pp. 340-354. https://doi.org/10.33012/2023.19399
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