Reduction of the Reconstruction Bias in Synthetic Aperture Imaging Radiometry

Synthetic Aperture Imaging Radiometers (SAIR) are powerful instruments for high-resolution observation of planetary surfaces at low microwave frequencies. This article is concerned with the reconstruction of radiometric brightness temperature maps from SAIR interferometric measurements. Even in the absence of modeling errors and radiometric noise, a systematic error, or bias, has been observed in the reconstructed maps. The origin of this bias is analyzed and an efficient solution is proposed for reducing it. Particular emphasis is laid on numerical simulations carried out for the SMOS space mission, a project led by the European Space Agency and devoted to the remote sensing of Soil Moisture and Ocean Salinity from a low orbit platform.