Improvement of the SMOS RFI Scenario
Oliva Balague, Roger1; Ruiz, Vicente1; Daganzo, Elena2
1ESAC, SPAIN; 2ESTEC, NETHERLANDS
European Space Agency's (ESA) Soil Moisture and Ocean Salinity (SMOS) mission was launched on 2 November 2009 with the objective of providing global observations for soil moisture and ocean salinity. SMOS carries the first-ever spaceborne L-band Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) in two dimensions. MIRAS operates within the Earth Exploration Satellite Service (EESS) passive band at 1,400-1,427 MHz, where all emissions are prohibited. However, despite the regulations SMOS' objective is disturbed by Radio Frequency Interference (RFI) that jeopardize part of its scientific retrieval in certain areas of the world, especially over continental areas in Europe, Southern Asia, and the Middle East.
In order to improve SMOS images over those areas, the SMOS team has put in place a plan to improve the RFI problem by requesting the countries to enforce regulations. For this the SMOS team needs to provide accurate coordinates of the RFI source to the national spectrum management authorities so they can locate the interference emitter and enforce those responsible to switch it off. This strategy was initiated early in the mission and has seen important improvements in the World RFI scenario, especially over North-America and Europe. Some good examples showing how the RFI situation can be reversed are shown in Figure 1. In total, more than 500 RFIs have been reported to the national countries and out of those, more than 200 cases have been successfully switched off.