Superresolving SAR tomography for multidimensional imaging of Urban areas: Compressive sensing-based TomoSAR inversion

Synthetic aperture radar (SAR) is capable of assessing the deformation of the ground and buildings in the order of centimeters and millimeters due to its coherent nature and short wavelengths. Spaceborne SAR systems are particularly suited for long-term monitoring of such dynamic processes. A single SAR image, however, only provides a two-dimensional (2-D) projection of the objects, which is in many cases noninjective (i.e., suffers from layover). To retrieve the real three-?dimensional (3-D) localization and motion of ?scattering objects, advanced interferometric methods, like persistent scatterer interferometry (PSI) or SAR tomography (TomoSAR), are required, which exploit stacks of complex-valued SAR images with diversity in space and time [1]?[6]. Modern spaceborne SAR sensors like TerraSAR-X, TanDEM-X, and COSMO-Skymed, provide data with very high spatial resolution (VHR) in the order of 1 m, which matches well with the scale of building features (typical floor height and window size and distance). This motivated the further development of existing TomoSAR techniques for exploring the potentials of VHR SAR data for urban infrastructure mapping [6]?[8]. In the last decade, conventional spectral estimation methods have been implemented for tomographic SAR imaging [3]?[6], [8]. However, for VHR urban monitoring, the ?following requirements should be met: