Ground movement measurement service | icgc

Ground movement measurement service

Sentinel 1 provides Synthetic Aperture Radar images that allow us to monitor surface movements with millimeter precision

ICGC has implemented a new service for queryng, visualization and downloading from the Ground motion measurements service viewer. The viewer allows you to choose the reference measurements, select the area in which you want to carry out the analysis by place name, load different background base maps, view time series of measured points and perform different visualization operations.

ICGC has developed its own interferometric processing chain to obtain ground motion measurements, with images from the Sentinel-1A/B satellites of the European Space Agency (ESA). These measures can be used in a wide range of cases, which include the maintenance of infrastructures, the monitoring of aquifers or the monitoring of landslides and underground mining.

The Ground Motion Measurement Service stores and manages radar images and processes them to obtain ground deformations. The viewer gives access to this large volume of data in an agile and simple way; by selecting the analysis area by toponym and graphically; choosing the reference measurements, loading different base maps, and performing different display operations of the time series of the measurement points. In this way, public and private actors can make use of this information for the study of different geological dynamics that affect the territory.

The viewer allows you to choose the reference measurements, select the area in which you want to perform the analysis by place name, load different base maps, consult the time series of the measurement points and perform different visualization operations.



Full window viewer


Obtaining the deformations of the terrain

ICGC has developed its own interferometric processing chain to obtain measurements of ground motions and additional algorithms that, using different acquisition geometries, ascending and descending orbits of the satellite, decompose the measurement into vertical and horizontal components of the motion .

The initial stage of satellite image processing is co-registration with respect to the geometry of the master acquisition. Subsequently, interferometric pairs are generated in which the topographical component of the radar signal is removed to obtain differential interferograms and the points that show interferometric coherence.

The candidate points to be measured using the Persistent Scatterer Interferometry (PSI) technique are those with greater coherence, where movement accuracies of around 3 or 4 mm can be obtained. The density of measurement points depends on the surface characteristics of the terrain. Urban and rocky areas have a high density of points while vegetated areas have a low density, due to what is known as temporal decorrelation. Areas with a low density of measurement points may be susceptible to the installation of artificial reflectors. The artificial reflectors or corner-reflectors are aluminum structures, which focused towards the orbit of the passage of the satellite ensure high quality measurement points. For its installation, a support base is necessary for the reflector and its subsequent alignment towards the orbit.

Dealing with the expettise in the analysis of satellite images of radar for the determination of subsidencies and moreover from the annual elaboration of a regional cartography of subsidencies of Catalonia, one of the emblematic projects in which the ICGC has carried out was concentrated over one of the most vulnerable areas of the territory. The LIFE EBRO-ADMICLIM project is a multidisciplinary project in the analysis and evaluation of mitigation and adaptation measures against climate change in the Delta de l'Ebre. The geoinformation data provided by the radar satellites over the Delta de l'Ebre allow us to estimate which areas in the last decades are presenting a greater instability or ground movements and therefore are candidates for major impacts due to the increase in the level of the sea sea.

Exemple d’anàlisi interferomètric

Exemple d’anàlisi interferomètric sobre la zona de les obres de la plaça de les Glòries sota la base temporal 2016-2021


Video. Ground movements: detecting, preventing and mitigating risks (2'59", Catalan)