Premiers résultats de la surveillance des déplacements terrestres à Paris (France) avec la série temporelle Sentinel 1 A / B
L’interférométrie différentielle SAR représente un outil efficace pour surveiller spatialement les petites déformations du sol.
Jauvin, Matthias (1); Yan, Yajing (1); Fruneau, Bénédicte (2); Trouvé, Emmanuel (1); Gusmano, Pierre (3) 1: LISTIC, Université Savoie Mont-Blanc, France; 2: Université Paris-Est Marne-la-Vallée, Equipe MATIS – IGN, France; 3: MIRE sas, France
Les grandes villes comme la ville de Paris connaissent des changements constants qui impliquent d’importants travaux de construction, à la surface et sous terre. Paris a par exemple lancé un nouveau projet appelé «Grand Paris», qui vise à transformer l’agglomération parisienne avec notamment des développements majeurs dans le réseau de transport (métro, train et tramway).
De tels projets sont généralement accompagnés d’un important pompage d’eau souterraine ou de grandes excavations, dont les impacts de surface doivent être surveillés avec précision pendant et après les opérations. Dans ce contexte, les données Sentinel 1 constituent une alternative prometteuse des images satellitaires radar(…)
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First Results Of Ground Displacement Monitoring In Paris (France) With Sentinel 1 A/B Time Series
SAR differential interferometry represents an efficient tool to spatially monitor small ground deformations. During the last fifteen years, methods based on image time series, such as Persistent Scatterers technique, have shown their capabilities for monitoring finer displacements with millimeter precision. With the launch of Sentinel 1A and 1B in April 2014 and 2016, it is now possible to work with free time series of medium resolution images. The rapid revisit time (6 days) of this new constellation limits the temporal decorrelation, which makes it possible to have a high PS density, especially in urban areas. This reduction of the distance between PSs would then reduce the dispersion of the displacement measurements, so that the main source of error in deformation measurement will be due to the variation of the atmospheric composition.
Major cities such as the city of Paris are experiencing constant changes that involve major construction works, both on the surface and underground. Paris for instance has started a new project called “Grand Paris”, which aims at transforming the Parisian metropolitan area with in particular major developments in transport network (subway, train and tramway). Such projects usually come with important pumping of groundwater or large excavations, whose surface impacts must be monitored with precision during and after the operations. In this context, Sentinel 1 data is a promising alternative of precedent radar satellite images, which guarantees the continuous availability of data for all applications and offers a good opportunity to develop operational monitoring applications. Even with a medium resolution, it is still possible to consider a use of this technique for monitoring displacements related to human activity (pumping of groundwater, construction of underground structures…) in urban areas.
In this paper, we will present our first results obtained with a stack of Sentinel 1A and 1B images (29 images from S1-A and S1-B already processed, probably 45 for the Fringe workshop) acquired in IW mode. The PS processing is performed by using Gamma software. Some specific areas where construction works have already started are currently investigated to try to identify meaningful displacement patterns. In order to avoid limitations such as difficult PS identification and wrong interpretation of the deformation, we consider integrating PS results in processes of monitoring with others geodetic measurements (GPS, tachometry or leveling) acquired by companies specialized in high-precision topography, in order to better analyze and understand the deformations, their related processes and risks.