Estimation of Sub-Canopy Ground Height from Capon TomoSAR profiles: A Performance Analysis

Synthetic Aperture Radar (SAR) waves at low frequency can penetrate through the different forest layers down to the ground. The received signal contains information not only on the 3-D distribution of the vegetation scatterers, but also on the underlying ground. Using multiple acquisitions, SAR tomographic (TomoSAR) techniques estimate vertical re-flectivity profiles, thus they enable the separation and localization of multiple backscattering contributions. The objec-tive of this paper is to discuss the capabilities of the Capon TomoSAR profiles in the estimation of the sub-canopy ground height by addressing the role of the TomoSAR acquisition configuration, the ground-to-volume ratio and the volume reflectivity profiles, and the technique used to identify the ground scatterer. The analysis is carried out by means of theoretical relationships and supported by airborne real L-band TomoSAR data acquired over a temperate forest site in the south of Germany.