摘要
Atmospheric phase delay,primarily caused by water vapor in the troposphere,is a major source of error in InSAR measurements,especially for land subsidence monitoring.This study integrates GNSS and GACOS data to correct tropospheric delay and enhance InSAR accuracy in Banting,Selangor.A total of 27 Sentinel-1A images,14GNSS stations,and 27 corresponding GACOS ZTD mapswere used tomonitor subsidence between 2023 and 2025.The InSAR data were processed using SNAP,StaMPS,and the TRAIN toolbox,incorporating both GNSS-and GACOS-derived ZTD corrections.The results show that applying atmospheric correction improved the estimated deformation range from−14.9 mm/year(min)and 9.1 mm/year(max)to−14.7 and 9.2 mm/year usingGACOS ZTD.Further enhancement was achieved by integrating GNSS and GACOS ZTD,resulting in deformation estimates ranging from−15.4 to 9.3 mm/year.Validation against reference GNSS data from the MERU MyRTKnet station revealed that the integrated correction yielded the lowest RMSE of 0.025,compared to 0.029 with GACOS-only correction and 0.03 without any correction.Overall,the integration of GNSS-and GACOS-derived atmospheric corrections significantly improved the accuracy of InSAR-based subsidence measurements,offering a promising approach for precise ground deformation monitoring in humid,tropical environments.
