Forest temporal decorrelation: 3D analyses and processing in the Diff-Tomo framework

Techniques based on coherent combination of complex (amplitude and phase) SAR data, in particular Pol-InSAR and 3D multibaseline SAR Tomography (Tomo-SAR), can extract rich information on complex scenarios with multiple scatterers mapped in the SAR cell. However, forest scenarios are characterized by a temporal decorrelating volume canopy scatterer, and a set of related open problems exists, in particular for Tomo-SAR techniques to be applied to space monitoring of biomass. Multipass/multibaseline 4D Differential Tomography (Diff-Tomo) is a promising advancement in this field, furnishing space-time signatures of multiple scatterer dynamics in the SAR cell, in particular with urban applications. In this paper, to deal with the forest decorrelation issues in Tomo-SAR, experimental advances are presented of the original extension of Diff-Tomo methods for analyzing vegetated scenes, to extract jointly geometric and dynamic information of forest layers. The Diff-Tomo enabled functionalities are separation in the height dimension of different temporal coherence levels that are mixed (undiscriminated) in classical total coherence analyses (“Tomography of coherences”), and 3D Tomography robust to temporal decorrelation. Extended airborne P-band multipolarimetric results and phenomenological investigations are shown.