Determining the accuracy of plasma irregularity geolocation from radio occultation observations

Currently there are many industries which are dependent on communications which pass through the ionosphere (e.g., GNSS). However, if plasma irregularities are located on the signal propagation path this can result in rapid fluctuations of the signal amplitude and/or phase, referred to as scintillation. Near-real time nowcasting of plasma irregularity positions can aid the mitigation of scintillation impacts to communications. However, most current techniques for irregularity geolocation nowcasting have limited efficacy in regions without ground-based observations (e.g., over oceans).

Irregularity Parameter Estimation (IPE) is a method which fits modelled power spectral density (PSD) functions to the PSD of a received signal. This provides estimates of plasma irregularity characteristics which can be used to determine the irregularity position. IPE can be performed on GNSS radio occultation (RO) observations, in which GNSS signals are detected by receivers located on satellites at lower altitudes. Therefore, IPE with RO observations can determine irregularity locations including in regions with limited ground-based observations. A method to rapidly perform IPE in near-real time is described and, for the first time, the accuracy of this method is assessed, comparing RO IPE irregularity geolocation with ground-based scintillation observations in the South American sector.