Sun effects in 2D aperture synthesis radiometry imaging and their cancellation

Abstract

The Microwave Imaging Radiometer by Aperture Synthesis (MIRAS) is the single payload of the European Space Agency’s (ESA) Soil Moisture and Ocean Salinity (SMOS) Earth Explorer Opportunity mission. MIRAS will be the first two-dimensional aperture synthesis radiometer for earth observation. Two-dimensional aperture synthesis radiometers can generate brightness temperature images by a Fourier synthesis process without mechanical antenna steering. To do so and have the necessary wide swath for earth observation, the array is formed by small and low directive antennas, which do not attenuate enough bright noise sources that may interfere with the measurements. This study analyzes the impact of the radio-frequency emission from the sun in the SMOS mission, reviews the basic image reconstruction algorithms, and proposes a technique to minimize sun effects.