Research On Method Of Building 3D Surface Deformation Model Based On GPS-InSAR Data Fusion

With the development and progress of space geodesy technology,GPS and InSAR,as two new types of ground observation technologies,have become increasingly important in crustal movement monitoring,geological hazard early warning and prevention.However,the advantages and disadvantages of these two types of technology are obvious.First of all,GPS technology can adjust the observation period according to the receiver frequency during ground observation,so it has a high time resolution,while InSAR is limited by the return period of SAR satellites,and its time resolution of ground observation is lower;Limited to the equipment purchase and installation costs,the ground observation model is a point observation with low spatial resolution,while the InSAR ground observation model is a large-area strip observation with high spatial resolution;finally,GPS monitors the accuracy of the ground surface horizontal deformation It is higher,and InSAR has higher monitoring accuracy for vertical upward deformation.In summary,the advantages of GPS technology and InSAR technology are highly complementary.The fusion of GPS and InSAR can not only meet the need for high temporal and spatial resolution of surface deformation monitoring,but also further improve the monitoring accuracy.Based on modern geodetic data processing theory,this paper has done some related research on GPS-InSAR fusion algorithm:1.A GPS-InSAR joint solution function model based on the fitting estimation method was proposed,and a systematic error fitting correction algorithm for InSAR observations was constructed,which significantly improved the accuracy of the GPS-InSAR joint solution for the three-dimensional deformation field on the surface.This paper starts with the inevitable systematic errors in InSAR observations,uses high-precision GPS 3D deformation as a priori information,and uses the InSAR imaging geometry to project high-precision GPS 3D deformation onto the InSAR line of sight to impose strong constraints on InSAR observations.The fitting estimation method is used to fit the systematic errors contained in the InSAR observations and to eliminate them,further improving the accuracy of the GPS-InSAR fusion solution for the three-dimensional deformation field on the ground surface.Simulation experiments and measured experiments verify that the GPS-InSAR joint solution functionmodel based on the fitting and estimation method can greatly improve the accuracy of the three-dimensional deformation field calculated.2.A joint solution model of GPS-InSAR data based on Kalman filter is proposed,which significantly improves the spatiotemporal resolution of the joint GPS-InSAR solution for the three-dimensional deformation field on the surface.This paper starts with the shortcomings of the existing GPS-InSAR data fusion processing method that greatly loses the time resolution of the observation data,and proposes a GPS-InSAR data fusion method based on the Kalman filter model to monitor the surface deformation,and fuses different sensors and The GPS and InSAR observation data obtained in different time spans from different imaging geometries can be used to obtain the three-dimensional surface deformation variables at each acquisition time of the deformation information.The algorithm was successfully applied to the extraction of Xi'an deformation field.Experimental results show that the method can not only break through the limitation of low resolution of a single technology,but also obtain a time-series3 D deformation field.3.The refined sliding distribution inversion of Wenchuan Mw7.9 earthquake was performed.The GPS-InSAR fusion algorithm model proposed above was applied to the 2008 Wenchuan Mw 7.9 earthquake,and a high-precision 3D deformation field in the earthquake area was obtained.With the obtained high-precision three-dimensional deformation field as a constraint,the fault slip distribution inversion of the Wenchuan earthquake rupture zone was performed using Okada elastic rectangular dislocation theory.The experimental results show that compared with the fault slip distribution results under a single data constraint,the high-precision 3D deformation field based on the joint GPS-InSAR solution can provide a more detailed inversion of fault slip distribution.