Abstract: The LuTan-1 (LT-1)satellite is China's first L-band differential interferometry SAR satellite,notable for its high spatial resolution,short revisit cycle,and full polarization capabilities.The current research on the application of SAR images acquired by this novel sensor is insufficient.The city of Hefei is chosen as the focal point for this study,where in three high-resolution radar images from LT-1 spanning July 2023 to May 2024 are utilized.To derive the surface subsidence deformation image of Hefei city,we employ the GACOS atmospheric correction model and delaunay minimum cost flow phase unwrapping method.The findings indicate that the ground deformation in Hefei city is generally smooth,with cumulative settlements in most areas ranging from -200～20 mm.However,certain local areas exhibit noticeable deformation trends.Five regions with significant deformation have been selected for a more detailed analysis,and their results have been compared with concurrent Sentinel observations,thereby validating the reliability of the LT-1 monitoring data.This study demonstrates that LT-1 imagery is capable of detecting finer deformation signals and providing higher-precision subsidence information,which can serve as vital support for urban safety and maintenance monitoring.

Key words: LT-1, GACOS atmospheric correction, D-InSAR, surface subsidence