Using SAR Satellite Data to Support Ground Deformation Monitoring at Road Construction Sites

Road construction sites often involve complex ground conditions, such as cut-and-fill slopes, rapid surface modification, and spatially heterogeneous deformation. While conventional in-situ monitoring systems, including inclinometers and GNSS, provide accurate point-based measurements, their applicability is limited by spatial coverage, particularly along long or inaccessible construction corridors. This study explores the feasibility of using spaceborne Synthetic Aperture Radar (SAR) data to support qualitative monitoring of ground deformation and slope behavior at road construction sites.

High-resolution X-band SAR data from TerraSAR-X and ICEYE were analyzed over a highway construction site in South Korea. Different observation geometries, including ascending and descending orbits as well as left- and right-looking configurations, were examined to assess slope visibility under varying terrain orientations. Geocoded gamma-nought and multilooked intensity images were used to qualitatively evaluate slope detectability and surface change patterns at different construction stages.

The analysis shows that SAR observation geometry strongly influences slope visibility in road construction environments. The availability of multiple viewing geometries from ICEYE improves the observation of slopes with diverse orientations along linear infrastructure corridors. High-resolution Spotlight imagery enables identification of small-scale cut slopes and construction-related surface changes, supporting site-scale qualitative monitoring. However, variations in incidence angle limit the suitability of ICEYE data for consistent quantitative deformation analysis. In contrast, TerraSAR-X provides more stable observation geometry, making it more appropriate when quantitative displacement assessment is required. 

These results indicate that SAR satellites can serve as an effective wide-area screening and complementary monitoring tool for road construction site management. SAR-based observations can assist in early identification of potentially unstable slopes, prioritization of field inspections, and integration with ground-based monitoring systems for infrastructure safety management.