# A GeoNode-Based Platform for an Effective Exploitation of Advanced DInSAR Measurements
## 2 DInSAR Techniques
The SBAS-DInSAR algorithm allows the investigation of ground deformation phenomena at two distinct spatial scales [31; 71]: (1) a regional one (medium resolution scale), where it exploits averaged (multi-look) interferograms to detect and analyse deformation phenomena relevant to map large areas, with a spatial resolution ranging from about 30 to 100 m; (2) a local one (full resolution scale), where the SBAS-DInSAR approach exploits single-look interferograms, i.e., generated at the full sensor spatial resolution (typically down to a few meters), to study local deformations that may affect buildings and man-made structures. Moreover, the multi-scale SBAS-DInSAR algorithm allows time series computation from multi-sensor SAR data acquired by different radar systems but with the same illumination geometry, as for the case of the C-band ERS-1/2 and ENVISAT sensors [72; 73] (see Figure 2). Accordingly, the SBAS-DInSAR approach allows generating LOS displacement maps and associated time-series spanning very long periods (decades), thus guaranteeing the continuity in  
Figure 2: The SBAS-DInSAR algorithm processing flow: from left to right, large number of SAR data are processed to generate a stack of interferograms with small temporal and spatial baselines, from which velocity deformation maps and deformation time-series are estimated. the monitoring of the Earth's surface deformation phenomena, as well as providing unprecedented information for studying long-term ground movements at different spatial scales. In recent years, the advanced DInSAR technologies have been rapidly changing to take into account the large availability of SAR data acquired by the so-called \"second generation\" satellite constellations, such as the X-band Italian COSMO-SkyMed (CSK) [74] and German TerraSAR-X (TSX) [75] systems. These new generation SAR systems are mainly characterized by a higher spatial resolution (of about 3 m for the stripmap mode, but potentially down to 1 m or less for the spotlight mode case) and a reduced revisit time (11 days for the TSX system, but as short as a few days for the CSK constellation) compared to the first generation SAR systems [34; 69], thus leading to the rapid creation of large SAR data archives. Moreover, massive SAR data volume is supplied by the C-band Sentinel-1 (S1) SAR constellation, which is composed by twin satellite systems, launched on 3 April 2014 and the 25 April 2016, within the framework of the Copernicus (formerly GMES) Programme of the European Union [35]. In particular, the S1 systems have been designed to work over land by exploiting the innovative acquisition mode referred to as Terrain Observation with Progressive Scans (TOPS) mode [76], which allows collecting SAR images, referred to as S1 Interferometric Wide Swath (IWS) scenes, with a spatial resolution comparable to that of the ERS and ENVISAT satellites, but with a very wide swath (about 250 km, see Figure 3), and a \"free and open access\" data policy. Moreover, where both the acquisition of the S1-A and S1-B satellite are available (the entire Europe, for instance) the revisit time is 6 days, thus allowing us to follow the temporal evolution of significantly rapid phenomena. Accordingly, innovative and appropriate solutions are needed to effectively and routinely exploit the huge amount of surface deformation measurements produced by these new generation SAR sensors through the available advanced DInSAR methodologies [77; 78].