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This paper presents a novel strategy for dam monitoring by repeat-pass SAR interferometry. The proposed approach couples sub-band / sub-aperture decomposition prior to the GLRT-LQ detector. This method is tested with spaceborne InSAR images provided by the TerraSAR-X satellite.

Abstract-Infrastructure monitoring applications can require the tracking of slowly moving points of a certain structure. Given a certain point from a structure to be monitored, in the context of available SAR products where the image is already focused in a slant range -azimuth grid, it is not obvious if this point is the scattering center, if it is in layover or if it is visible from the respective orbit. This paper proposes a refocusing procedure of SAR images on a set of measured points among with a 4D tomography based scattering center detection. The refocusing procedure consists of an azimuth de-focusing followed by a modified back-projection on the given set of points. The presence of a scattering center at the given positions is detected by computing the local elevation-velocity plane for each point and testing if the main response is at zero elevation. The refocusing and scattering center detection algorithm is validated on real data acquired with the TerraSAR-X satellite during March-June 2012. The mean displacement velocities of the detected scatterers show good agreement with the in-situ measurements.

Infrastructure monitoring applications can require the tracking of slowly moving points of a certain structure. Given a certain point from a structure to be monitored, in the context of available SAR products where the image is already focused in a slant range -azimuth grid, it is not obvious if this point is the scattering center, if it is in layover or if it is visible from the respective orbit. This paper proposes a scattering center monitoring procedure based on refocusing a set of SAR images on a provided high-resolution DEM of the structure. The scattering centers of the refocused image are detected in the 4-D tomography framework by testing if the main response is at zero elevation in the local elevation-velocity plane obtained using the Capon estimator. The displacements of the scattering centers are computed from the estimated velocity spectrum. The algorithm is validated on real data acquired with the TerraSAR-X and TanDEM-X satellites over the Puylaurent dam in France during March-June 2012. The relative displacements between scattering regions show very good agreement with the in situ measurements.