Multifrequency InSAR height reconstruction through maximum likelihood estimation of local planes parameters

In this paper, a technique able to reconstruct highly sloped and discontinuous terrain height profiles, starting from multifrequency wrapped phase acquired by interferometric Synthetic Aperature Radar (SAR) systems, is presented. We propose an innovative unwrapping method, based on a Maximum Likelihood Estimation technique, which uses multifrequency independent phase data, obtained by filtering the interferometric SAR raw data pair through nonoverlapping band-pass filters, and approximating the unknown surface by means of local planes. Since the method does not exploit the phase gradient, it assures the uniqueness of the solution, even in the case of highly sloped or piece-wise continuous elevation patterns with strong discontinuities.