Performance Limitations for the Phase Screen in the Settings of Transionospheric SAR

Low-frequency transionospheric radar is affected by large- and small-scale inhomogeneities of the ionospheric electron number density causing phase perturbations of the radar pulses. These perturbations may lead to distortions in the synthetic aperture radar (SAR) images. Phase corrections may be implemented by means of a phase screen, which is an approximation of the actual "thick" ionosphere by an infinitesimally thin layer of plasma. We evaluate the accuracy that can be achieved using such a representation. We will consider a large-scale setup due to the atmospheric gravity wave and a small-scale scenario represented by the turbulence.