Morphology of Shape and Drift of Ionospheric Irregularities and GPS Scintillation Statistics

On its way from the satellite to the receiver, a trans-ionospheric radio signal is distorted by the ionospheric irregularity that causes signal delay, changes in signal's phase and amplitude, hence producing a complicated diffraction pattern on the ground. The variability of the ionospheric drifting irregularity shape and small scale statistics, reflects the ionospheric behaviour during quiet and storm events, influencing the signal propagation. The purpose of this investigation is to infer the characteristics of the ionospheric irregularities from those of the scintillation diffraction pattern. Plasma drift velocity and irregularity geometry are studied through the eigen-analysis of the cross-correlation matrix of gradients of the scintillation pattern. As far as the scintillation statistics of the GPS signal is concerned, the study of probability distributions of the signal fluctuations at different scales provides important information useful in applications. This study has been performed on radio signal phase and power recorded by GPS monitors located at high latitudes at Hornsund, Svalbard and at near equatorial site in Brazil. Data covers periods before, during and after some major events in 2010-2011. We validated the estimated properties of ionospheric irregularities using additional independent measurements.