Abstract

Transionospheric radio signals might undergo random modulations of their amplitude and phase caused by scattering on irregular structures in the ionosphere. This phenomenon, known as scintillation, is governed by the space weather conditions, time of the day, season, local distribution of the geomagnetic field, etc. All these factors make ionospheric scintillation both highly variable in space and time. Moreover, scintillation are intrinsically anisotropic since the associated scattering irregularities tend to align and stretch along the geomagnetic field lines. Depending on the relative position of signal source, the receiving station, and the irregularity, the scintillation effect on the transmitted wave might be enhanced or reduced. This study is focused on the consistent accounting of this geometric effect in scintillation modeling with the emphasis on situations when the communication or sensing sender-receiver link is nearly horizontal. For this task the single phase screen model has been used to model the scattering of propagating radio signals on random ionospheric layer. The geometric enhancement effect of scintillation is demonstrated by considering communication links via a geostationary beacon satellite over the equator.