Date of Award

Fall 2019

Access Type

Dissertation - Open Access

Degree Name

Doctor of Philosophy in Aviation


College of Aviation

Committee Chair

Steven Hampton


The ground-based augmentation system (GBAS) is a safety-critical system consisting of the hardware and software that augments the Global Positioning System (GPS) to provide precision approach and landing capability and is one of the navigational cornerstones of the International Civil Aviation Organization's (ICAO) global transition to space-based technologies. In low latitude regions, where the space-based augmentation system (SBAS) cannot provide adequate precision approach service due to large system errors induced by ionospheric delays, GBAS is the best option to provide the primary navigation function for the modernized global air traffic system. The purpose of the study was to identify patterns of ionospheric event behavior during nighttime hours to determine if the hours of operation and availability of CAT I service for GBAS operations at Galeao airport in Rio de Janeiro, Brazil, can be expanded beyond hours established by the GBAS safety case. This study investigated the potential correlation of scintillation to time, azimuth, satellites in view, and satellite elevation as these variables pertain to operational safety (use of the system). The study included analysis of GBAS approach operations based on system performance, ionospheric activity, and satellite geometry to establish safe levels of service, Category (CAT) I or higher, during periods of increased ionospheric activity. The analysis was conducted utilizing archived system performance data collected from the GBAS installation located at Galeao International Airport and ionospheric data collected from the Rede Brasileira de Monitoramento Continua do GPS, as well as three reference receivers installed on the Galeao airport. The goal of the research was to determine the impact of scintillation, if any, on the ability of GBAS to support low latitude precision approach operations. The results of the study provided information critical to development of the safety case for GBAS operations to possibly support System Design Approval (SDA)/certification by Brazil and lay a foundation for development of operational mitigations. The research may be applicable to all commercial aircraft conducting GBAS operations in low latitude regions around the world, approximately± 20° of the magnetic equator.

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