Stabilized image reconstruction algorithm for synthetic aperture imaging radiometers

It is now well established that synthetic aperture imaging radiometers promise to be powerful sensors for high-resolution observations of the Earth at low microwave frequencies. Within this context, the European Space Agency (ESA) is currently developing the SMOS (Soil Moisture and Ocean Salinity) mission. The Y-shaped array selected for SMOS is fitted with equally spaced antennae and leads to natural hexagonal sampling grids. This article deals with the reconstruction of radiometric brightness temperature maps over such grids from interferometer measurements. The corresponding inverse problem is stated without any reference to the numerical method that could be used to solve it. To support the theory, numerical simulations are presented and analyzed with emphasis on stability and error analysis.