New differential SAR tomography functionalities for probing 3D forest structure and dynamic processes

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.