Modeling the Earth’s Ionosphere by a Phase Screen for the Analysis of Transionospheric SAR Imaging

In the problems of transionospheric synthetic aperture radar (SAR) imaging, autofocus, and ionospheric tomography, the Earth’s ionosphere is often represented by a phase screen. A key advantage of the phase screen is that it reduces the overall dimension of the model. Yet, this convenient simplification comes at a price of introducing inaccuracies into the modeled quantities, such as the phase of the propagating radar signals. In this work, we develop the appropriate metrics to quantify these inaccuracies and evaluate their role for two particular scenarios: SAR imaging through large-scale ionospheric disturbances due to the atmospheric gravity waves (AGWs) and SAR imaging through ionospheric turbulence.