On the impact of propagation disturbances on SAR Tomography: Analysis and compensation

This paper is meant to discuss the role of propagation disturbances, such as those due to atmospheric disturbances or to residual platform motion, in SAR Tomography applications. It will be shown that phase stability requirements vary as a function of the number of targets within the system resolution cell, from which it follows that SAR Tomography applications require a higher phase stability, or a more accurate phase calibration, with respect to SAR Interferometry. Phase calibration will be discussed by comparing two approaches. The first is the traditional approach from Permanent Scatterers Interferometry, based on the assumption that it is possible to find stable targets in the imaged scene. The second is a new technique based on the Sum of Kronecker Products Decomposition, recently introduced in literature, which allows to isolate ground and volume contributions within the data provided the availability of multi-polarimetric acquisitions. As such, the latter approach is suited to carry out phase calibration in presence of volume scattering, as it is the case of forested areas. Experimental results will be provided basing on the analysis of the P-Band data-set relative to the forest site of Remningstorp, Sweden.