Ground-Based Augmentation System Operation in Low Latitudes - Part 2: Space Weather, Ionospheric Behavior and Challenges

Abstract

Ionospheric dynamics over low latitudes, especially in Brazil, are highly active, with several phenomena resulting from the complex interaction between space weather and atmospheric elements. These phenomena may cause disruptions to aviation communications, navigation and surveillance systems. Motivated by the issues posed by the ionosphere to the operation of ground-based augmentation of global navigation satellite systems (GNSS) in Brazil, this review paper presents fundamental physical aspects of space weather and low-latitude ionospheric dynamics to show how and why the ionosphere over Brazil is much more challenging for satellite-based positioning technologies. Solar influence, geomagnetic field configurations under quiet and storm periods, and the ensuing ionospheric dynamics over low latitudes occasionally lead to the development of structures known as equatorial plasma bubbles. These structures can produce strong plasma gradients within the ionosphere and cause scintillation on transionospheric signals. The consequences of these structures for GNSS users are specifically addressed.