Auroral Ionospheric Irregularity Properties via Estimation and Inverse Modeling of GNSS Scintillations

When Global Navigation Satellite System (GNSS) signals traverse the ionosphere, variations in plasma density cause the received signal at the ground to scintillate, i.e., exhibit a rapid fluctuation in power and/or phase. Scintillation at high latitudes near the auroral zone can be frequent, and are typically observed, with standard GNSS receiver processing, as phase scintillations. Scintillation is an undesirable effect for navigation purposes, because it degrades signal quality and can lead to poor tracking, cycle slips, and loss of lock on satellites needed for robust positioning. One of the challenges to understanding the irregularities producing scintillation is that they are not directly sensible with established sensing methods such as incoherent scatter radar. A motivating premise behind this work is that, while undesirable for navigation, scintillation of a received signal is beneficial for ionospheric study because it can be used to investigate the properties of and the physical mechanisms producing exactly those irregularities that scatter the signal.