Ground deformation mapping by fusion of multi-temporal interferometric synthetic aperture radar images: a review

Interferometric synthetic aperture radar (InSAR) has emerged as a powerful geodetic imaging technique in the past two decades, focused on the retrieval of deformation, topography and even meteorological measurements by the analysis of phase components of complex-valued radar data. The strength of this technique lies in its abilities of all-weather, day and night data acquisition, high measurement accuracy and wide spatial scale. Although vast successful applications have been achieved, conventional InSAR technique possesses several limitations (e.g. decorrelation, phase unwrapping error and atmospheric artefacts), which, in turn, have motivated the development of advanced multi-temporal InSAR (MTInSAR) analysis techniques. Fusion of MTInSAR imagery of the same area has led to a marked improvement in the reliability and accuracy of derived products (e.g. deformation) and has also been important for gleaning dynamic signals of deformation over a wide range of temporal scales. This paper is intended to introduce the development of MTInSAR and provide a practical guidance to the users of the technique. Specially, cross-comparison among approaches employed by different MTInSAR techniques is conducted using either simulated or real datasets. We have addressed the weakness of each approach and highlighted the potential technical improvement.