SMOS RFI mitigation using array factor synthesis of synthetic aperture interferometric radiometry

Abstract

Radio frequency interference (RFI) is one of the most significant limiting factors in the retrieval of geophysical parameters measured by microwave radiometers. In this work, based on the measured visibilities of European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission, RFI mitigation results are presented using two approaches of array factor synthesis of synthetic aperture interferometric radiometry, i.e., RFI mitigation based on null control and low sidelobe synthesis. Results show that, for the approach of array factor synthesis with null control, the Gibbs-like contamination of weak and moderate RFIs can be mitigated very well, but it is not enough effective for strong RFIs because of instrument errors. On the other hand, for strong RFIs, at the cost of spatial resolution degradation which may be not critical for ocean salinity retrieval, result shows the approach of low sidelobe synthesis can be effective to mitigate the Gibbs-like contamination of strong RFIs.