Deformation monitoring of bridges applying remote sensing satellite radar measurements

Deformations of the Earth's surface can be measured from space using remote sensing radar interferometry (InSAR). This paper demonstrates the use of these data for deformation monitoring on the Schottwienbr & uuml;cke-S6 Semmering motorway. The European Space Agency (ESA) recently began providing free research satellite data from the Sentinel-1 mission. The approach uses historically recorded natural reflection points as well as corner reflectors artificially attached to the structure. These are measured coordinately and analyzed using remote sensing methods. Thermal displacements of the structure are compensated to increase accuracy. A new model predicts the temperature of the structure based on network weather data. This means that the deformation measurements from the satellites can be analyzed and thermally compensated without sensors on the building, and the deviations can be more than halved. The recorded and processed annual measurements from 2022 onwards show a standard deviation of 1.7 to 3.0 mm compared to the reference system (Liquid Leveling System). Good agreement with the long-term settlement behavior of the bridge was also found for natural reflection points. Satellites can also be used to simultaneously record different structures at 6-day intervals up to 2016. Due to the time-delayed processing, they are currently well suited for long-term deformation monitoring of long-span bridges.