A Research Of SBAS-InSAR Technology Based On Sentinel-1 Data In Surface Deformation Monitoring

Interferometric Synthetic Aperture Radar(InSAR)as an emerging space-to-earth observation satellite remote sensing technology,has the advantages of high coverage,high precision,high sensitivity and can unaffect by the weather,and is widely used in the detection of surface information.And Differential InSAR(D-InSAR)is developed on InSAR technology,which can detect small deformations of the ground.However,due to the influence of spatio-temporal and atmospheric decoherence,D-InSAR technology has certain defects.Fortunately,SBAS-InSAR technology can well overcome the influence of spatio-temporal and atmospheric decoherence,and has a very wide range of application prospects in surface deformation monitoring.Surface deformation monitoring has always been a key area of concern in China.In recent years,surface deformation has caused various degrees of damage to many parts of China.The combination of natural factors and human factors is an important cause of surface deformation.Natural factors mainly include tectonic subsidence,earthquakes,volcanic activities,etc.,and China is a country with frequent earthquake disasters.The 5.12 Wenchuan earthquake and the Lushan earthquake in Sichuan not only caused huge casualties and heavy economic losses,but also induced a large number of secondary geological disasters in the affected areas,which brought a huge impact on the subsequent reconstruction of the earthquake-stricken areas.Sentienl-1 data is widely used in deformation monitoring because of short time intervals,data acquisition easily,high practical and which can effectively avoid the influence of climatic conditions.However,in recent years,Sentienl-1 data are generally used for urban land subsidence monitoring and are rarely used in mountain terrain monitoring.Therefore,some mountainous areas in the 5.12 earthquakestricken area are selected as research areas to process the sentinel data using InSAR technology and to discuss the feasibility of SBAS-InSAR technology for large-scale surface deformation monitoring.At the same time,the deformation of some disaster areas after the 5.12 earthquake in recent years is obtained,in order to provide reference for the prevention and control of some secondary disasters.The main research contents are as follows:(1)According to the research purpose of this paper,the Sentinel-1 data in IW imaging mode is selected as the data source to preprocess the 3 scene sentry data,and on this basis,the basic processing flow of multi-temporal Sentinel-1 data is explored.This study is intended to provide a reference for the setting of data parameters in the subsequent processing of InSAR technology.(2)InSAR technology is used to process Sentinel-1 data.Based on the ground elevation information of the study area,the DEM data obtained by InSAR is compared with the ASTER GDEM V2 data to evaluate the accuracy of DEM,and the causes of the error are analyzed.(3)The surface deformation is monitored by the two-track D-InSAR technique.In this paper,the external DEM is used to remove the topographic information to obtain the deformation phase of the study area initially,then the interference processing is performed to obtain the deformation map of the study area.The SBAS-InSAR technique is used to process the 27 sentinel data,and the time series deformation during the monitoring period is inverted to obtain the deformation rate of the study area.(4)By analyzing the deformation results obtained by D-InSAR technology and SBAS-InSAR technology,the deformation of the study area is obtained,and the causes of deformation are analyzed which provides reference for subsequent deformation monitoring and disaster prevention.Finally,based on the recent monitoring results of landslide time series deformation of Maoxian and Daguangbao,the feasibility of SBAS-InSAR technology in surface small deformation monitoring is discussed in research areas.