Equatorial Plasma Bubble Threat Parameterization to Support GBAS Operations in the Brazilian Region. Issue 3 (17th September 2017) - Yoon, Moonseok
Abstract: The Brazil ionospheric study project aims to develop a new ground‐based augmentation system (GBAS) ionospheric threat model to better reflect Brazil's low‐latitude conditions. Data processing from the global navigation satellite system for 123 active ionospheric days identified 1017 anomalous ionospheric gradients caused by nighttime equatorial plasma bubbles (EPBs). A significant number of gradients, including the largest verified gradient of 850.7 mm/km, exceed the upper bound (375–425 mm/km) of the conterminous United States (CONUS) threat model. This paper defines a series of parameters to model the geometry of EPBs. A maximum ionospheric delay drop of 35 m and a transition zone between 20 and 450 km are estimated for EPBs that move roughly eastward and parallel to the geomagnetic equator with speeds between 40 and 250 m/s. These parameters are key to the development of a GBAS ionospheric mitigation and safety case for operational approval in Brazil and other low‐latitude locations. Copyright © 2017 Institute of Navigation