Small-scale ionospheric irregularities and their effects on GNSS - A status Report

Trans-ionospheric radio signals of global navigation satellite systems (GNSS) like GPS, GLONASS, GALILEO and BeiDou may suffer from rapid and intensive fluctuations of their amplitude and phase caused by small-scale irregularities of the ionospheric plasma. Such disturbances occur frequently in the equatorial region during the evening hours due to plasma flow inversion or during geomagnetic storms in the polar region. This phenomenon is called radio scintillation and can strongly disturb or even disrupt the signal transmission. We like to present an overview of the latest results as well as present and future work with respect to monitoring, modelling and forecasting of small-scale ionospheric irregularities. We will also discuss the scintillation impact on GNSS and possible mitigation measures. The work presented are results from the Working Group 4.3.5 of IAG Sub-Commission 4.3.