Geological Subsidence Deformation Detection Method Based On BDS-InSAR Data Fusion

Aiming at the problem of land subsidence in mining areas,two important spatial geodetic techniques,Bei Dou Navigation Satellite System(BDS)and Interferometric Synthetic Aperture Radar(InSAR),are used to detect the deformation of geological subsidence in mining areas.Different time-series InSAR techniques are used to detect the deformation of a large area in the mining area,while BDS is used to detect the continuous three-dimensional deformation of discrete points in the mining area.In this thesis,on the one hand,BDS high-precision deformation data is used to correct the orbit error generated in the process of time-series InSAR processing,and the overall accuracy of InSAR deformation detection is improved.On the other hand,the BDS-InSAR data fusion is realized by using the temporal and spatial correlation of the two kinds of data to solve the three-dimensional deformation of the surface and increase the temporal and spatial resolution and detection accuracy of the settlement deformation detection.The main research contents of the thesis are as follows:1.The geological subsidence analysis of mining areas is carried out based on different time series InSAR algorithms,including Stanford method for persistent scatters(StaMPS)and Small Baseline Subsets InSAR(SBAS-InSAR).By comparing the settlement detection results of the two methods,the relative accuracy of the InSAR results is verified.Further comparison with BDS settlement data shows the reliability of InSAR settlement detection results.2.Based on the quadratic surface fitting model of orbital error,a uniform control point selection method is proposed in SBAS-InSAR processing.This method first divides the study area into equal sub-areas,and uses the coherence coefficient and amplitude dispersion index.The sub-region control points are screened,and then the ground control points evenly distributed in the entire study area are obtained through iteration,and the BDS station is introduced into it as a control point.Finally,the orbit error is fitted according to the quadratic surface model,and the orbital error is subtracted from the wrapping phase diagram to improve the accuracy of the final deformation detection result.Experiments are carried out in the diamond mining area,and the comparison of settlement detection results shows that this method can improve the monitoring accuracy of SBASInSAR as a whole.3.A BDS-InSAR data fusion method that can increase the spatiotemporal resolution of deformation detection is proposed,which uses the deformation amount and deformation rate of the previous moment to predict the deformation amount at the current moment,and uses the BDS deformation amount and the InSAR deformation amount at the current moment to correct the prediction result to obtain high-precision threedimensional deformation value and high-precision settlement deformation value at the same time.The method is applied to the settlement detection in the diamond mining area.The experimental results show that the method not only increases the time resolution of the detection results,but also improves the accuracy of the settlement detection.