The interest for advanced methods of full 3D SAR imaging of volumetric forest scatterers is rapidly increasing. In particular, multibaseline SAR tomographic elevation beamforming i.e. spatial spectral estimation is a promising technique. Recently, this concept has been integrated with the differential interferometry concept, producing the new differential tomography mode which yields ‘space-time’ signatures of scattering dynamics in the SAR cell. Based on this framework, we develop new tomographic functionalities to allow extracting geometric and dynamic information of forest layers. First, we show a new tomographic method robust to temporal decorrelation, arising during the synthesis of the tomographic array. A parametric method matched to non-line spectra is applied to decouple the nuisance temporal signal histories in the spatial spectral estimation. Second, we propose a new differential method aiming to overcome the limitations of classic differential interferometry in scenarios with interfering volumes. In particular, we focus on the possibility of monitoring subcanopy ground subsidences. Finally, a last new functionality is proposed to retrieve information on different temporal decorrelation mechanisms of overlayed scatterers. Simulated and first airborne real data results are reported.
['Fabrizio Lombardini', 'Francesco Cai']
New differential SAR tomography functionalities for probing 3D forest structure and dynamic processes