196,305 research outputs found
Quality assessment of interferometric SAR DEMs
No full textA new interferometric SAR (InSAR) procedure for DEM generation was employed to generate different DEMs from ERS SAR image pairs. The procedure was validated comparing the InSAR DEMs with a suited reference DEM. In the first part of the paper the principal features of the procedure are briefly summarised. The second part is focused on the quality assessment of the InSAR DEMs. They cover the same test area and come from one ascending SAR image pair, one descending pair and from the fusion of data coming from ascending and descending images. The analysis includes the influence of the SAR image coherence, the degradation of the DEM quality related to the terrain topography and the artefacts due to atmospheric effects
Early detection and in-depth analysis of deformation phenomena by radar interferometry
No full textAbstract
The spaceborne differential interferometric SAR (DInSAR) technique may play an important role in the measurement of land deformation phenomena, especially in urban, suburban and industrial areas. In order to fully exploit its capabilities and increase its operational use, this paper proposes two complementary levels of analysis. The first one is a comprehensive low-cost screening, in order to detect unknown subsidence phenomena over large areas. This analysis, which provides a first estimation of deformations, has to be performed using a limited set of SAR images. The second level includes an in-depth quantitative analysis based on large image stacks, which requires more image acquisition and data processing resources. This type of analysis can be typically used to study deformation phenomena of special relevance, where an effective support to the decision-makers requires a fully quantitative estimation of deformations. The two levels of analysis were proved over a test area of about 2100 km2, located in Catalonia (Spain). Without any a priori information, seven deformation phenomena were detected using a reduced set of interferograms. Furthermore, the quantitative analysis of a subsidence of small spatial extent, which was based on ascending and descending datasets, confirmed the capability of DInSAR to quantitatively assess deformation phenomena.
Keywords
Subsidence;
Deformation;
Monitoring;
Remote sensing;
SA
Pasquasia potassic salts mine (Central Sicily, Italy): ground deformation phenomena pointed out by means of Differential SAR Interferometry (DInSAR)
No full text
Editorial for the special issue "urban deformation monitoring using Persistent Scatterer Interferometry and SAR tomography"
No full textThis Special Issue hosts papers related to deformation monitoring in urban areas based on two main techniques: Persistent Scatterer Interferometry (PSI) and Synthetic Aperture Radar (SAR) Tomography (TomoSAR). Several contributions highlight the capabilities of Interferometric SAR (InSAR) and PSI techniques for urban deformation monitoring. In this Special Issue, a wide range of InSAR and PSI applications are addressed. Some contributions show the advantages of TomoSAR in un-mixing multiple scatterers for urban mapping and monitoring. This issue includes a contribution that compares PSI and TomoSAR and another one that uses polarimetric data for TomoSAR
Sentinel-1A/B imagery for terrain deformation monitoring: a new strategy for Atmospheric Phase Screening (APS) estimation
No full textThis work focus on terrain deformation monitoring by means of C-band Synthetic Aperture Radar (SAR) Sentinel-1A/B imagery exploiting the Persistent Scatterer Interferometry (PSI) technique. The deformation monitoring strategy described in this article is related to a specific monitoring scenario where a relatively small urban area is potentially affected by deformation and its surroundings are stable. In the case study considered in this work, the scenario corresponds to an area of potential subsidence induced by underground water pumping covering an area of interest with a radius of approximately 1 km. The proposed monitoring strategy takes advantage of the specific scenario at hand and, in particular, of the availability of stable areas in the vicinity of the area potentially affected by ground deformation, to estimate the Atmospheric Phase Screen (APS), i.e. signal propagation delay caused by the Earth’s atmosphere, in an attempt to minimize the underestimation of the deformation rate.Grant numbers : DEMOS (CGL2017-83704-P)
Spaceborne Differential SAR Interferometry: Data Analysis Tools for Deformation Measurement
No full textThis paper is focused on spaceborne Differential Interferometric SAR (DInSAR) for land deformation measurement and monitoring. In the last two decades several DInSAR data analysis procedures have been proposed. The objective of this paper is to describe the DInSAR data processing and analysis tools developed at the Institute of Geomatics in almost ten years of research activities. Four main DInSAR analysis procedures are described, which range from the standard DInSAR analysis based on a single interferogram to more advanced Persistent Scatterer Interferometry (PSI) approaches. These different procedures guarantee a sufficient flexibility in DInSAR data processing. In order to provide a technical insight into these analysis procedures, a whole section discusses their main data processing and analysis steps, especially those needed in PSI analyses. A specific section is devoted to the core of our PSI analysis tools: the so-called 2+1D phase unwrapping procedure, which couples a 2D phase unwrapping, performed interferogram-wise, with a kind of 1D phase unwrapping along time, performed pixel-wise. In the last part of the paper, some examples of DInSAR results are discussed, which were derived by standard DInSAR or PSI analyses. Most of these results were derived from X-band SAR data coming from the TerraSAR-X and CosmoSkyMed sensors
Resolving vertical and east-west horizontal motion from differential interferometric synthetic aperture radar : The L'Aquila earthquake
No full textAnalysis of surface coseismic displacement has already been obtained for the 6 April 2009 L'Aquila (central Italy) earthquake from differential interferometric synthetic aperture radar (DInSAR) data. Working jointly on ascending and descending DInSAR data makes for a step forward with respect to published preliminary estimates: we process data in order to retrieve a continuous displacement pattern, both in the vertical and horizontal directions, the latter being limited to the eastward component because of the low sensibility of the SAR images used to resolve northward motion. Our analysis provides new insights on the horizontal component of displacement, obtaining a clear picture of eastward displacement patterns over the epicentral area. This result is noteworthy, as until now little information has been available on horizontal displacement following normal-fault events in the central Apennines (Umbria-Marche, 1997, and L'Aquila, 2009), given the lack of dense GPS networks, the only available source of horizontal displacement data in this area. Inverted fault characteristics from such data also show noteworthy differences compared to previous studies, localizing the Paganica fault as the causative fault for the earthquake
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