RFI mitigation of SMOS image based on CLEAN algorithm

Aperture synthesis measurements, also termed complex visibilities, are the sparse samplings in the (u,v) frequency plane, which causes undesirable side lobes in the synthesized beam. Through the side lobes, artificial sources emitting in the protected 1400-1427MHz band are contaminating the retrievals of the soil moisture and ocean salinity (SMOS) satellite launched by the European Space Agency (ESA) in November 2009. An effective way to correct the artificial interferences is to create a synthetic signal as close as possible to the interference and subtract it from the measured data. Based on the same idea, in this paper, we describe an approach to compensate for the effect of interference iteratively, which uses the CLEAN algorithm that was first developed to deconvolve a map made up of some point sources in radio astronomy. It works by finding the brightest point and then removing its contribution iteratively. Experiments based on real SMOS data have been carried out to demonstrate that the proposed algorithm is effective in correcting the influence of RFIs.