Urban Land Deformation Monitoring Based On Time Series InSAR Technology

Urban land deformation is mainly divided into lifting effect and subsidence effect.When the deformation effect develops to a certain stage,it will become a geological disaster.Among them,land subsidence disasters are most common in urban areas,which not only cause damage to building infrastructure,but also cause casualties and economic losses.Nowadays,the research on land deformation is still based on traditional methods(GPS network,leveling network,etc.).However,due to the limitations of traditional monitoring methods,such as difficulty in surface sampling,large manpower and material resources,and long monitoring period,it is still difficult to meet the urban surface deformation and fine-grained monitoring requirements.Based on this,the emergence of a new remote sensing time series InSAR monitoring technology has solved this technical problem.The technology has the characteristics of full time period,high precision,full coverage observation and low cost,which makes the technology become the application hotspot of monitoring urban land subsidence research.Due to the complicated geological,hydrological and climatic conditions,Fuzhou is also suffering from the comprehensive influence of the southeast coastal seismic belt and various large-scale above-ground and underground construction of Engineering,which poses a serious potential risk of land subsidence.In the past,the research on monitoring land deformation in Fuzhou City is still scarce.It is very useful to use the new InSAR monitoring technology to extract the land deformation information in the near future.Firstly,this paper reconstructs the latest surface elevation data model(DEM)during the monitoring period by using InSAR technology and TerraSAR radar image data,and then extracts the land deformation information of Fuzhou city from 2013 to 2015 by reconstructing DEM model and TerraSAR data set with time series SBAS-InSAR technology.Based on the statistical analysis methods of point-line and point-flour,it is found that relatively strong land subsidence occurred in some linear transportation hubs(bridges,subway lines)and planar areas(Jin an District,Longhua District)during the monitoring period,which is highly consistent with the actual survey results.Finally,using the acquiredGPS data and level data for the experiment InSAR data results have been carefully evaluated for accuracy.The statistical analysis results show that the relative accuracy values of the InSAR results for the first two monitoring techniques in the corresponding time period are all millimeters.It can be considered that the results of the InSRA experiment are scientific and reliable,and it is also feasible to apply InSAR technology to fine monitoring of urban land deformation.