DESDynI adopts hybrid polarity SAR architecture

DESDynl-Deformation, Ecosystem Structure, and Dynamics of Ice-is one of the first-tier missions recommended in The National Research Council´s Earth Science 2007 Decadal Survey. DESDynI´s L-band synthetic aperture radar (SAR) is designed to measure terrain surface deformation and forest biomass, hence its quadrature-polarimetric SAR mode. The objective to provide quantitative information on a global scale imposes severe requirements on the radar to maximize coverage and to sustain reliable operational calibration. These requirements are best served by the hybrid-polarity architecture, in which the radar transmits in circular polarization, and receives on two orthogonal linear polarizations, coherently, retaining their relative phase. This architecture offers many significant advantages over conventional all-linearly-polarized SARs. This paper reviews those advantages, summarizes key attributes of hybrid-polarity dual- and quadrature-polarized SARs including conditions under which the signal-to-noise ratio is conserved, and describes the evolution of this architecture from first principles.