Monitoring and analysis of subsidence along Lian-Yan railway using multi-temporal Sentinel-1A InSAR

Multi-temporal interferometry synthetic aperture radar (MT-InSAR) has the capability to monitor deformation with millimeter precision over wide areas. It has been widely applied for the monitoring of land subsidence. In recent years, much attention was paid on monitoring of the subsidence along large-scale man-made linear features represented by high speed railway(HSR) with MT-InSAR. This paper conducts a tentative test for applying C-band SAR data to the deformation monitoring of HSR subgrade, phase stability analysis and improved StaMPS technology were jointly used to increase the point density and stability of deformation parameter solution. In this paper, a total of 47 Sentinel-1A images spanning 21 months were processed for MT-InSAR analysis along Lian-Yan HSR, and the accuracy of linear deformation velocity and time-series deformation were evaluated respectively by the data of continuous BDS (BeiDou navigation satellite system) monitoring station. The results demonstrate that C-band Sentinel-1A data is capable of achieving millimeter accuracy in linear deformation velocity and time-series deformation, the mean root mean square error (RMSE) value of time-series displacement differences between the InSAR and the BDS is 3.8 mm, agreed well with BDS monitoring data, and the overall performance of Lian-Yan HSR is stable.