This study is focused on wide-area deformation monitoring initiatives based on the differential interferometric SAR technique (DInSAR). In particular, it addresses the use of advanced DInSAR (A-DInSAR) techniques, which are based on large sets of synthetic aperture radar (SAR) and Copernicus Sentinel-1 images. Such techniques have undergone a dramatic development in the last twenty years: they are now capable to process big sets of SAR images and can be exploited to realize a wide-area A-DInSAR monitoring. The study describes several initiatives to establish wide-area ground motion services (GMS), both at county- and region-level. In the second part of the study, some of the key technical aspects related to wide-area A-DInSAR monitoring are discussed. Finally, the last part of the study is devoted to the European ground motion service (EGMS), which is part of the Copernicus land monitoring service. It represents the most important wide-area A-DInSAR deformation monitoring system ever developed. The study describes its main characteristics and its main products. The end of the production of the first EGMS baseline product is foreseen for the last quarter of 2021.

This research is related to the eco-hydrological problems of the herbaceous wetland drying and biodiversity loss in the floodplain lakes of the Middle Basin of the Biebrza River (Poland). An experiment was set up, with its main goals as follows: (i) mapping the vegetation types and the temporarily or permanently flooded areas, and (ii) comparing the usefulness of the C-band Sentinel-1A (S1A) and X-band TerraSAR-X/TanDEM-X (TSX/TDX) for mapping purposes. The S1A imagery was acquired on a regular basis using the dual polarization VV/VH and the Interferometric Wide Swath Mode. The TSX/TDX data were acquired in quad-pol, a fully polarimetric mode, during the Science Phase. The paper addresses the following aspects: (i) wetland mapping with the S1A multi-temporal series; (ii) wetland mapping with the fully polarimetric TSX/TDX data; (iii) comparing the wetland mapping using dual polarization TSX/TDX subsets, that is, the HH-HV, HH-VV and VV-VH; (iv) comparing wetland mapping using the S1A and TSX/TDX data based on the same polarization (VV-VH); (v) studying the suitability of the Shannon Entropy for wetland mapping; and (vi) assessing the contribution of interferometric coherence for wetland classification. Though the experimental results show the main limitations of the S1A dataset, they also highlight the good accuracy that can be achieved using the TSX/TDX data, especially those taken in fully polarimetric mode. Some practical outcomes significant for the study area management using SAR were also described.

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This paper describes a Persistent Scatterer Interferometry procedure to process Sentinel-1 SAR data. Its most original part includes a set of tools to perform two key processing stages: a first 2 + 1D phase unwrapping, prior to atmospheric filtering, and a second 2 + 1D phase unwrapping, to generate the deformation time series. These tools address two fundamental aspects of a Persistent Scatterer Interferometry processing chain: the quality control of the intermediate and final results, and the generation of quality indices to characterise such results. The effectiveness of the proposed tools is illustrated using a case study located in Catalonia (Northern Iberian Peninsula).

This paper focuses on bistatic coherence as an additional feature complementing amplitudes in classification space, permitting to monitor temporal changes in water extent on the wetland comprising surface water and inundated vegetation. The research was conducted on a herbaceous wetland. The TanDEM-X (TDX) images were acquired during the science phase: in bistatic mode with long perpendicular baselines. Two different sets of observations were computed: polarimetric amplitudes and interferometric coherences in single-pass mode. Next, the datasets composed of a multitemporal stack of images were classified using objectbased image analysis (OBIA). The main outcome of the experiment is that bistatic coherences increased greatly the overall accuracy of expected thematic classes. The overall accuracy (OA) shows that thematic categories were classified with higher accuracy when the bistatic coherence complemented polarimetric amplitudes. The OA is greater than 85% for all analyzed datatakes. The accuracy achieved using amplitudes only was higher than 70% but varied overtime. The bistatic coherence at X-band turned out to be really helpful in mapping high vegetation, which can be an indicator that this methodology can be directly used in the monitoring of common reed mowing or mapping highly invasive vegetation. Additionally, we could observe that short inundated vegetation was also mapped correctly, allowing flooded areas in this floodplain to be mapped with great precision throughout the growing season.