Effects of ionospheric inhomogeneities on remote sensing of the earth by space-borne P-band SAR

Numerical modeling of the effect of the polarization vector rotation in the ionospheric plasma on the radio waves of the high frequency range is performed. The relevance of the work is associated with the creation of space-based P-band synthetic aperture radars (SARs) for the Biomass mission and the MKS-RSA (P) experiment on board ISS station. These instruments are intended for surface and subsurface sounding of the Earth and their readings are strongly influenced by the ionosphere. Another problem of EM propagation is the reconstruction of the profile e-ionospheric plasma density by radio tomography methods. The source of radiation is located on the moving spacecraft at a distance of 400 km from the Earth's surface. The angle of rays inclination varies from 150 to 30° relative to the horizontal axis. The receiver is located on the surface of the Earth. Three spherical two-layer models of the ionosphere are compared. To determine the ray paths, a bi-characteristic system of equations is used. The dependence of the aiming angle deviation on group time is investigated. The phase variation due to the influence of the ionosphere and the angle of the Faraday rotation are studied. It is shown that the changes in the Faraday rotation angle for the selected parameters lie in the range from 6° to 54°, which will have a strong impact on the operation of the P-band SAR and requires a sufficiently accurate quantitative account of the variability of the angle when probing vegetation and soil covers.