Quantitative analysis of Faraday rotation impacts on image formation of spaceborne VHF/UHF-SAR

The performance of spaceborne synthetic aperture radar (SAR) at lower frequencies, such as VHF/UHF bands, is affected by ionosphere effects, especially Faraday rotation (FR). A quantitative analysis of Faraday rotation impacts on spaceborne VHF/UHF-SAR image formation is presented in this paper. The error models of FR resulting from calm Total Electron Content (TEC) and fluctuant TEC, for Linearly Polarized (LP) and Dual Circularly Polarized (DCP) mode, are established. The simulation results indicate that for LP mode Faraday rotation effect on azimuth signal can be neglected, while the range signal is seriously affected, bur for DCP mode, the error in both range and azimuth signals is negligible. Therefore, DCP mode is a better choice to decrease the effect on image focusing caused by FR effect.