This paper focuses on multi-pass spaceborne synthetic aperture radar interferometry (InSAR) in presence of distributed scattering, paying particular attention to the role of target decorrelation in ...the estimation process. This phenomenon is accounted for by splitting the analysis into two steps. In the first step we estimate the interferometric phases from the data, while in the second step we use these phases to retrieve the physical parameters of interest, such as LOS displacement and residual topography. This approach is suited both to derive the performances of InSAR with different decorrelation models and for providing an actual estimate of LOS motion and DEM. Results achieved from Monte-Carlo simulations and a set of repeated pass ENVISAT images are shown.
SAR data gathered from forested areas collect contributions coming from the vegetation layer, from the ground below and from other scattering mechanisms (SMs). Multi-baseline data allow a tomographic ...analysis thus retrieving information about the vertical structure of the target. Multi-polarimetric acquisitions enrich the data, providing ways to identify the targets basing on their electromagnetic properties. The joint exploitation of multi-polarimetric and multi-baseline data suggests the possibility of linking the estimation of the vertical structure of different SMs with their polarimetric signature. A formal framework in which this task can be accomplished is provided by the Algebraic Synthesis (AS) technique, which extends the concepts within PolInSAR through the assumption of the Sum of Kronecker Products (SKP) structure. By assuming the presence of two SMs (for example ground and volume scattering), the SKP assumption leads to a cross dependence between the polarimetric and interferometric coherences, in that ground structure is shown to be related to volume polarimetry, and dually volume structure is shown to be related to ground polarimetry. The aim of this paper is to investigate the implications of this cross relation. Experimental results will be shown basing on a data-set of multi-polarimetric and multi-baseline SAR images at P-band acquired by DLR's E-SAR over the Krycklan catchment, in northern Sweden, in the framework of the ESA campaign BioSAR 2008.
This work deals with the estimation of terrain topography from multi-pass Synthetic Aperture Radar (SAR) interferometry (InSAR), focusing on the case where the variation of the system geometry within ...the imaged swath is relevant, as in airborne multi-pass interferometric campaigns. The space varying nature of the system geometry gives rise to a major issue in multi-pass InSAR analyses, in that it prevents from compensating for the presence of interferogram phase offsets by simply phase locking the data stack to a reference point, therefore hindering the retrieval of terrain topography. To cope with this issue properly we propose a novel approach that exploits the algebraic properties of the problem. Such an approach allows to cast the problem in terms of identification of a null space component for terrain topography, after which both topography and the interferogram phase offsets are quickly obtained without exploiting calibration points.
An automatic power control system based on arrays of four optical variable attenuators, realized in glass-on-silicon technology, is proposed. The application to a specific optical equipment is then ...reported and the main features and performances are highlighted.
