Ionospheric Irregularities Response to the April 2023 Major Geomagnetic Storm: A European Perspective

The ionosphere plays a critical role in the propagation of Global Navigation Satellite System (GNSS) signals. However, ionospheric irregularities, such as scintillation and electron density fluctuations, can significantly impact the performance of GNSS applications. Scintillation in trans-ionospheric signals, such as those used by the Global Positioning System (GPS), is caused by electron-density irregularities in the ionosphere. As these signals pass through the irregularities, they experience rapid and unpredictable changes in signal strength, resulting in amplitude and phase fluctuations. These fluctuations can lead to degraded receiver performance in several ways, from accuracy issues, such as range errors, to the loss of signal tracking [Paula et al. 2003]. Thus, obtaining reliable information about key parameters that describe the ionosphere's perturbation level is crucial for ensuring the required safety standards. The occurrence and intensity of ionospheric scintillation depend on factors like location, time, and the Earth's magnetic field. Despite decades of study, research gaps persist, primarily due to the need for specialized high-rate GNSS receivers.