Error propagation analysis in the processing of sar images for subsidence measuraments

Abstract

Every measurement of the physical world is affected by uncertainty, no matter how precise the available instruments are. In other words, a measure completely free of errors is not possible. Being able to quantify this uncertainty, or, equivalently, the distribution of the errors is of the most fundamental importance, as it determines the validity of any experiment or procedure. The Coherent Pixel Technique (CPT) is a technique developed by the Remote Sensing Laboratory (RSLab) of Universidad Politcnica de Catalunya (UPC) for the interferometric processing of satellite data. The objectives of CPT are the generation of altimetry and land displacement velocity maps, starting from the Synthetic Aperture Radar (SAR) acquisitions. The phase of these complex images already contains topographic information on the illuminated area. From it, the Persistent Scatter Interferometry (PSI) methodology allows the creation of deformation velocity maps over the interest area. This work studies in depth part of the CPT technique, in the context of terrain deformation analysis. In particular, it is necessary for the final user to have a measure of the uncertainty on the results. This work addresses the problem for the specific case of the CPT, providing maps of the uncertainty that help to determine the reliability of each pixel.