RFI Mitigation in Aperture Synthesis Radiometers Using a Modified CLEAN Algorithm

For aperture synthesis radiometers, sparse samplings on the $u$ -$v$ frequency plane cause undesirable sidelobes in the synthesized beam. Through these sidelobes, artificial sources emitting in the protected 1400-1427 MHz band contaminate the retrievals of the soil moisture and ocean salinity (SMOS) from MIRAS measurements. One effective way to correct the artificial interferences is to create a synthetic signal to compensate for the interference's impact. Based on the similar idea, in this letter, we describe an algorithm to compensate for the interference's impact by constructing an artificial signal as close as possible to the Gaussian beam. Numerical studies using synthetic and real SMOS data have been carried out to demonstrate that the proposed algorithm outperforms the classical CLEAN algorithm in correcting the impact of the extended radio frequency interference source.