Infrastructure and utilities

Engineers and planners are facing various challenges during the asset's life cycles:

• site selection and construction planning
• construction monitoring
• infrastructure operational monitoring

To evaluate structural stability and surface deformations we offer scalable and customizable solutions based on a suite of multi-temporal satellite interferometry (MT InSAR) techniques. The solution is applicable both to high-resolution (Sentinel-1) and very-high resolution (commercial) satellite data depending on detail needed by customers. It allows us to monitor assets of linear, area or spot-like nature. Deformations detected for objects indicate problems of structural nature or subsoil settlement. Ground motions detected in near or wider surroundings are mostly related to threats induced by ground subsidence, slow slope deformations or undermining.

Roads and railways

MT InSAR technique helps to prevent damages or potential collapse of embankments as markers derived from measurement time series can indicate forthcoming failure. Detected deformation patterns can be correlated with measurements from traditional monitoring systems (geodetic and GNSS, water pressure gauges, inclinometers, temperature and precipitation measurements) and existing survey networks. Monitoring from multiple directions helps determine real vectors of displacements. We have developed custom single- and double-flip design of artificial corner reflectors accustomed to mounting directly to infrastructure objects or nearby.

Tunnels and undermining

Gisat provides detection of extent, grading and chronology of ground settlements during and after shallow tunnel drilling - e.g. subway, road underpassess and tunnels in urban areas. Sinking bowl resulting from drilling or ground water withdrawal impacts structural stability of infrastructure and buildings on surface. MT-InSAR allows regular evaluation of stability during ongoing construction phases and raise alarm amid displacement exceeding warning state. Comparison of deformation rate chronology supports evidence-based assessment of potential damage causalities and transfer of liability.

Bridges

Though challenging due to mixing up with thermal dilatation and other influencing factors, long time series of InSAR measurements allow us to detect certain deformations patterns for parts of bridge structures. We have developed a multicriterial methodological framework for assessing MT InSAR feasibility for bridge monitoring that facilitate finding feasible and cost effective monitoring solutions for specific bridge characteristics

Revitalisations and recultivations

Interferometry provides insight into uneven distribution of soil consolidation and velocity for large dump sites. Measurements from currently or formerly operational satellites provide either up-to-date or historic dump settlement rates spanning as far back as to the 1990's. Results from our interferometric solution facilitate calibration of geotechnical ground-settlement models to provide more accurate projections of the consolidation process.

Dams and tailing dams

Satellite interferometry helps identify tailings dam’s weak points that are subject to higher rates of deformations where other risky patterns can be detected from deformation trend lines. Detected deformations can be temporally correlated to oscillations of liquid levels in the reservoir.

Artificial corner reflectors

Topographic and ground surface characteristics, vegetation and snow cover and stochastic nature of target detection (persistent or distributed scatterers) may hinder deformation mapping under certain circumstances. To overcome this caveat, a network of artificial corner reflectors can be installed within the area of interest. Such a network allows all-season monitoring and connection to existing survey networks and measurements.

Assets change detection

Assets operators need to react to changes occuring in protective corridors along the linear infrastructure and utility networks. Illicit activities such as unpermitted built-up, earthworks or dumping may impose direct risks to traffic or proper operations, or introduce additional costs for maintenance or legal and administrative procedures. Besides anthropogenic factors, vegetation volume, height and health represents another phenomena that need to be tackled in scope of management plans in order to assure full operability of the networks.

The above mentioned phenomena can be mapped from commercial very high resolution imagery. For large linear networks and grids, however, automated solutions with reduced cost for data are demanded. Our solution is based on detection of changes and indicators (markers) from long time series of high resolution data from Sentinel-1 (radar, all weather) and Sentinel-1 (optical) imagery. Results indicate potential objects of interest or vegetation growth hot-spots to be inspected by targetted field survey or UAV technology.