Assessment of Decorrelation and Deformation Monitoring Accuracy in Geosynchronous SAR Interferometry

Interferometric synthetic aperture radar (InSAR) has emerged as a powerful tool for surface deformation monitoring. Conventional low Earth orbit (LEO) SAR systems are constrained by narrow swath widths and long revisit intervals, limiting their applicability in large-scale and rapid-response scenarios. Although satellite constellations partially address these issues, they introduce increased system complexity and operational costs. In contrast, geosynchronous SAR (GeoSAR) offers significantly shorter revisit intervals, on the order of hours rather than days, and much wider swath coverage, expanding from the hundred-kilometer scale of LEO SAR to the thousand-kilometer scale. These advantages make GeoSAR a promising solution to the limitations of LEO SAR systems. However, its decorrelation characteristics and deformation monitoring performance remain insufficiently understood. This study provides a quantitative analysis of key decorrelation sources, including thermal, spatial, temporal, Doppler centroid, and processing-induced decorrelation, and further evaluates the deformation measurement accuracy of GeoSAR using differential interferometric SAR, persistent scatterer interferometry, and the small baseline subset technique. Results indicate that GeoSAR is less susceptible to spatial decorrelation, and that, given a fixed number of acquisitions and invariant decorrelation conditions, longer revisit intervals can significantly enhance the accuracy of deformation measurements. These findings provide valuable insights into the potential of GeoSAR for surface deformation monitoring.