Differential Tomography: Evolutions of SAR Interferometry for Analyzing Complex Non-Stationary Scenarios

1 — Much interest is growing in advanced interferometric SAR methods for full 3D imaging. Multibaseline SAR tomographic elevation beam forming, i.e. spatial spectral estimation, is a promising technique in this framework. Recently, this concept has been integrated with the differential interferometry concept, producing the advanced differential tomography processing mode which produces ‘space-time’ signatures of scattering dynamics in the SAR cell. In this paper, the use of this new framework is investigated in critical scenarios of multiple scattering with temporal signal variations, both from scatterer deformation motions and scatterer temporal decorrelation. The first scenario is related to deformation velocity estimation in layover urban areas. Differential tomography algorithms are experimented to extend classical differential interferometry operation, using real ERS-1/2 data and continuing the first tests. The second scenario is related to elevation focusing of temporal decorrelating volume forest scatterers. After analysing blurring effects of conventional tomography and performance bounding in this condition, differential tomography based algorithms for 3-D imaging robust to temporal decorrelation are presented. Simulated performance analysis and first real E-SAR data results are reported.