On the estimation of interferometric phases for multibaseline SAR interferometry using a relaxation-based technique

In this paper, we examine how one can exploit baseline diversity of a multichannel interferometric SAR system to overcome the layover problem. The problem arises when different height contributions collapse in the same range-azimuth resolution cell, due to the presence of strong terrain slopes or discontinuities in the sensed scene. We propose a multilook approach to counteract the presence of the time-and-space varying amplitude distortion which is due to the extended nature of natural targets; to this purpose we extend a recent relaxation based approach by estimating the interferometric phases using a nonlinear least squares estimation technique that is based on a deterministic modelling of the amplitude distortion.