SAR tomography

SAR tomography extends the conventional 2D SAR imaging to 3D, by synthesizing a synthetic aperture in the direction normal to the range-azimuth plane, by using multiple acquisitions taken from slightly different viewing angles. This additional dimension directly provides the solution of the target elevation ambiguity problem faced by the conventional SAR which cannot separate targets appearing in the same range cell despite their different elevations. The image profile in the normal-to-slant range direction (elevation) separates these targets. Differential SAR tomographic techniques simultaneously allow modeling the motion parameters of one or more scatterers in addition to their elevation. In this way, differential SAR tomography can be used as a technique for deformation assessment.

Combined use of PSI and SAR tomography is being investigated to improve deformation analysis in urban regions and alpine territories.

Enlarged view: Point cloud obtained with SAR tomography — 3D point cloud of coherent scatterers obtained with SAR tomographic inversion on an interferometric stack of 50 TerraSAR-X stripmap images. The scatterers are shown projected on Google Earth 3D building models. The colors represent the estimated parameters. The observed area is an commerical center (Diagonal Mar) in Barcelona city, Spain.