Preliminary Definition of Navigation System Performance for SA CAT I Approaches Based on GNSS Guidance

Denis Bouvet, Jean-Pierre Arethens

Abstract:	The Synthetic Vision Guidance System (SVGS) allows Category I (CAT I) operations to be improved into Special Authorization Category I (SA CAT I) operations towards a CAT I runway end, with Decision Heights below 60 m (200 ft), down to 45 m (150 ft). The SVGS combines a Synthetic Vision System (SVS), which allows faster acquisition of visual references, and additional on-board monitoring of the navigation signal used during the instruments phase. These on-board monitors enable lower minima to be targeted, and to decrease the Runway Visual Range (RVR), as the CAT I lighting elements provide closer visual references at reduced decision height (DH). The SVGS concept has already been developed and validated to support SA CAT I operations down to 150 feet, when a CAT I ILS provides the navigation signal used during the instrument phase of the approach. Within the framework of the PJ02-W2 AART ‘Airport airside and runway throughput’ of the SESAR 2020 programmei, the objective of solution PJ.02-W2-17.4c ‘Synthetic Vision Guidance System (SVGS) for approach operation on LPV or GLS CAT I guidance’ is to extend the SVGS assistance concept to support precision approach on CAT I runways with minima lower than 200ft when using GNSS/SBAS guidance. The main technical challenges for the extension of the SVGS with SBAS CAT I guidance supporting LPV200 approaches are related to the use of a navigation signal during the instrument phase, ensuring the airworthiness of the landing or go-around phase. They include: - The definition of a set of high-level navigation performance requirements in terms of accuracy and integrity, supporting the intended operations; - The definition of the airborne monitors providing improvement of the SBAS CAT I navigation performance to support the airworthiness of the targeted operations. The paper describes how the set of high-level navigation performance requirements characterizing the vertical positioning error has been defined to support SA CAT I operations with SVGS using a GPS/SBAS navigation signal for guidance during the instrument phase of the approach.
Published in:	Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022) September 19 - 23, 2022 Hyatt Regency Denver Denver, Colorado
Pages:	154 - 165
Cite this article:	Bouvet, Denis, Arethens, Jean-Pierre, "Preliminary Definition of Navigation System Performance for SA CAT I Approaches Based on GNSS Guidance," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 154-165. https://doi.org/10.33012/2022.18299
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