Generation of Earth's surface Three-Dimensional (3-D) Displacement Time-Series by Multiple-Platform SAR Data

In this Chapter, the recent advancements of differential SAR interferometry (DInSAR) technique are presented, with the focus on the DInSAR-based approaches that lead to the generation of three-dimensional time-series of Earth's surface deformation, based on the combination of multi-platform line-of-sight (LOS)-projected time-series of deformation. Use of pixel-offset (PO) measurements for the retrieval of North-South deformation components, which are difficult to be extracted from DInSAR data, only, is also discussed. A review of the principal techniques based on the joint exploitation of the amplitude and phase signatures of sequences of SAR images will be first provided, by emphasizing the limitations and the strength of each single approach. Then, the interest will be concentrated on the recently-proposed multi-track/multitemporal InSAR combination algorithm, referred as Minimum Acceleration InSAR Combination (MinA) approach. The algorithm assumes the availability of two (or more) sets of SAR images acquired from complementary tracks. SAR data are pre-processed through one of currently available multi-temporal DInSAR toolboxes (Permanent Scatterers and/or Small Baseline oriented), and the Line-of-sight (LOS)-projected surface deformation time-series are computed. An under-determined system of linear equations is then solved, based on imposing that the 3-D displacement time-series have minimum acceleration (MA). The presented results demonstrate the validity of the MinA algorithm. Additional experimental results will also be presented to highlight the significance of the combined use of SAR-driven amplitude and phase information for the temporal analysis of large deformations (with rates on the order of several centimetres per year) of the Earth's crust.