Evaluating European Ground Motion Service against Local InSAR Analysis along Key Swedish Corridors

Abstract. Ground motion poses a significant threat to the safety and functionality of transport infrastructure, particularly in regions affected by landslides, subsidence, freeze–thaw processes, and large-scale tunnelling. Interferometric Synthetic Aperture Radar (InSAR) enables millimeter-level displacement monitoring over large areas and is used to support infrastructure risk assessment. Here, we evaluate the usability of two InSAR approaches, (i) Persistent Scatterer Interferometry (PSI) using displacement products from the European Ground Motion Service (EGMS), and (ii) a combined Persistent- and Distributed-Scatterer (PS+DS) phase-linking workflow across key Swedish transport corridors. Rather than a strictly controlled methodological comparison, we evaluate how differences between operational InSAR solutions translate into practical performance for infrastructure monitoring. Results show that PS+DS consistently yields five times as many measurement points while maintaining RMSE values within a similar range to EGMS (mostly below 6 mm in the Line Of Sight direction). The EGMS exhibits narrower RMSE distributions, but PS+DS achieves comparable median RMSE of the measurement points across most land-cover types and corridor environments. Both datasets capture similar displacement patterns along all corridors, with measurement points from both approaches concentrating within the linear corridor geometry. Overall, the five-fold increase in PS+DS point density offers infrastructure operators a practical pathway to finer-scale ground motion monitoring for railway maintenance and risk assessment, while demonstrating how the choice of operational InSAR processing strategy shapes the information available for Earth-observation-based infrastructure applications.