• ionosphere
• ionospheric tomography
• polarimetry
• SAR polarimetry
• synthetic aperture radar
• tomography

Spaceborne synthetic aperture radar (SAR) acquisitions are distorted by the propagation of the transmitted and backscattered pulses through the ionosphere especially at low frequencies. The knowledge of the free electron concentration in the slant range direction in terms of (slant) total electron content (TEC) is critical to correct the amplitude, phase and polarization distortions in SAR images. TEC values can be obtained from precise measurements of Faraday rotation, enabled by the availability of fully polarimetric SAR data. However, an accurate conversion of Faraday rotation to TEC requires the knowledge of the (slant) electron density profiles. Conventional ionosphere mapping techniques can not provide these profiles with the necessary spatial/temporal sampling and resolution for an operational use. As a consequence, evaluating the possibility to obtain them from the SAR data themselves is an important issue.
Tomographic reconstructions of the electron density profiles in the plane defined by the orbit and the slant range direction can be obtained from Faraday rotation measurements in multiple azimuth sub-bands.