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First demonstration of 3-D holographic tomography with fully polarimetric multi-circular SAR at L-band

This paper presents the first 3-D polarimetric holographic tomograms at L-band using fully polarimetric multi-circular SAR (MCSAR) over forested areas. This concept offers an innovative way of analyzing the Earth, in particular volume scatterers such as forested areas, ice and dry soils. Holographic tomograms are formed by low-frequency radar in L-band and by the acquisition of multi-angular measurements with MCSAR over 360°. MCSAR consists of the combination of CSAR with an additional synthetic aperture in height (z). The analysis of the impulse response function (IRF) of MCSAR shows 3-D sidelobe reduction and an improvement in the resolution along the z direction. A fully polarimetric MCSAR campaign using the DLR's F-SAR airborne system at L-band over the region of Kaufbeuren, Germany was carried out. Images in 3-D were focused with beamforming (BF) and compressive sensing (CS). Results depict advantages of MCSAR such as shadow reduction, low temporal decorrelation and a better understanding of the coherent 3-D radar backscattering.