Weighted subspace fitting of interferometric phases for multibaseline SAR interferometry

In this paper, we deal with the problem of exploiting 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. The multilook framework is adopted to counteract the presence of the space varying distortion, termed speckle, which is due to the extended nature of natural targets; to this purpose we introduce a weighted subspace fitting approach to estimate the interferometric phases. Although the approach does not take the speckle into account, it is found to yield estimates superior to previously examined methods.