A Framework of Provincial Ground Motion Service Using L-Band LuTan-1 InSAR Data for Geological Hazard Monitoring

Wide-area, high temporal resolution ground deformation measurements are crucial for geological hazard identification, continuous monitoring, and risk assessment. Interferometric Synthetic Aperture Radar (InSAR) has become an important technique for acquiring ground deformation information due to its all-weather, day-and-night observation capability and high measurement precision. LuTan-1 (LT-1) is China’s first interferometry-oriented SAR twin-satellite formation operating at L-band. Since its launch in 2022, LT-1 has collected a large volume of high-quality SAR data, demonstrating strong potential for deformation measurement. However, delivering stable, reliable, and operational wide-area ground motion services with LT-1 remains challenging because of the limited swath width in stripmap imaging, the complexity of multi-track acquisitions, and pronounced long-wavelength systematic errors that lead to inconsistencies across tracks.

To address these issues, we propose a provincial-scale ground motion service framework for geological hazard monitoring using LT-1 InSAR data. The framework enables automated multi-track InSAR processing, systematic errors correction, and routine generation of consistent wide-area deformation products. We first process LT-1 SAR data to generate multi-track InSAR deformation results. We then apply a large-look-based method to correct systematic errors in each InSAR deformation result. Exploiting the distinct spatial characteristics of the long-wavelength error component versus the true deformation signal, we select an appropriate large-look window and upsample to estimate and remove systematic errors, thereby reducing inter-track discrepancies. A unified reference frame is subsequently established, and the corrected multi-track results are resampled and integrated using weighted averaging to produce a seamless provincial ground motion result.

We used Shaanxi Province as the study area. The results showed that after correction, the mean absolute error (MAE) decreased by approximately 2 mm, and long-wavelength systematic errors were effectively suppressed. Comparison with contemporaneous Sentinel-1 (S-1) deformation results showed strong consistency in deformation trends. Approximately 150 deformation results covering the entire province were mosaicked in about 2 hours, demonstrating a good balance between accuracy and efficiency. The results were integrated into routine geological hazard monitoring workflows, and joint interpretation with optical imagery enabled the detection and delineation of potential hazard sites, providing data support for hazard surveillance and risk assessment. Similar to the European Ground Motion Service (EGMS), we have developed a provincial-scale ground motion monitoring service based on LT-1 data. The system can generate monthly updated deformation maps, providing a basis for near-real-time monitoring.