Differential SAR interferometry for the monitoring of land subsidence along railway infrastructures

The paper summarizes the results of an ongoing research project carried out in cooperation between CTTC (Spain) and the University of Milan (Italy). The work aimed at investigating the role of quality indicators in the analysis of differential interferometric SAR time series products. Small baseline multi-temporal differential interferometric techniques have been used to derive TS products from six-year Sentinel-1 images covering railway networks in Barcelona, Spain. Redundancies of interferograms and post-phase unwrapping phase estimation residuals were pivotal parameters in determining the reliabilities of measurements. Preliminary results have supported the importance of quality indicators as well as the feasibility of multi-temporal differential interferometric techniques in monitoring subsidence along railway infrastructures. The time series evolutions of measurements from coherent scatterers have also shown that the target area is stable in the study period. AGAUR, Generalitat de Catalunya, has partially funded this work through a grant to recruit early-stage research staff (Ref: 2021FI_B2_00186).