Advanced D-InSAR techniques applied to a time series of airborne SAR data

This paper presents airborne differential SAR results using a stack of 14 images, which were acquired by the experimental SAR (E-SAR) system of the German Aerospace Center during a time span of only two and a half hours. An advanced differential technique is used to retrieve the error in the digital elevation model and the temporal evolution of the deformation for every coherent pixel in the image. The two main limitations in airborne SAR processing are analyzed, namely the existence of residual motion errors (inaccuracies in the navigation system in the order of 1-5 cm), and the accommodation of the topography and the aperture during processing. The SAR focusing chain to process the data is also presented, together with the modifications in the differential processor to deal with the remaining baseline error. The detected deformation of a corner reflector and of several agricultural fields allows validating the proposed techniques.