SMOS RFI Experience in the 1400-1427Mhz Passive Band Due to Radiations at Intermediate Frequency of Satellite Home-TV Receivers

SMOS is the European Space Agency's (ESA) mission addressing the need for high-quality global observations of soil moisture and ocean salinity from space. SMOS operates in a dusk-dawn sun synchronous near circular orbit at 763 km, with 6pm descending node. The payload consists of the Microwave Imaging Radiometer with Aperture Synthesis (MIRAS) operating in the 1400–1427 MHz purely passive band. This band is a primary allocation to the passive remote sensing in the Earth Exploration Satellite Service (EESS (passive)) by the ITU Radio-Regulations (RR). Although all emissions are prohibited in this band (RR No. 5.340), since its launch in November 2009, the SMOS science data have been polluted by Radio Frequency Interference (RFI) worldwide. Among the causes of interference detected by SMOS, one of the most unexpected and difficult to eliminate, is due to the aggregate radiations from the intermediate frequency (IF) circuits of satellite home-TV receivers in Japan. Since October 2011, this type of interference case is detected in SMOS observations over the country, in particular in urban areas with high density of population.