A New Method for Urban Subsidence Monitoring Using Time Series InSAR Combining Tandem: A Case Study of Pazhou Island

With the rapid development of Guangzhou's economy and urbanization and the gradual deepening of the urban planning and development system, various types of engineering construction activities have become increasingly frequent, and different degrees of ground subsidence have appeared in some areas of the city.Traditional InSAR technology is greatly affected by terrain residuals when monitoring surface deformation.To improve the accuracy and resolution of the digital elevation model and remove the terrain residual phase is the key to improve the monitoring accuracy of temporally interferometric SAR deformation.Based on the TerraSAR-X and tandem X acquisition of high-precision DEM, this paper proposes a Tandem-assisted sequential interference SAR (permanent scatterer) technology, 21 views of ENVISAT/ASAR data and 56 views sentinels on Pazhou Island in Guangzhou City - 1 The data was processed to obtain high-precision monitoring results of surface subsidence and spatio-temporal evolution of urban areas in the study area.The experimental results show that the DEM extracted by TSX/TDX can significantly improve the accuracy of temporally interferometric synthetic aperture radar, and proves that this method has a good effect and application potential in the monitoring of urban surface subsidence.