Mount Everest Time Series InSAR Surface Deformation Monitoring Based On Optimal Dual Polarization Channel

Surface deformation monitoring is beneficial to the harmony between human and nature.Traditional measurement methods(level measurement and satellite positioning system measurement)do not have unique advantages such as fast,all-weather,all-day and low cost.Synthetic aperture radar interferometry(In SAR)measurement technology has been developed so far,and synthetic aperture radar differential interference(DIn SAR)measurement technology is limited by time,spatial decoherence and atmospheric effects.At present,the newly proposed permanent scatterer synthetic aperture radar interferometry(PSIn SAR)technology not only overcomes the difficulties of DIn SAR technology,but also its accuracy of monitoring deformation rate is close to millimeter level,which has wide application in surface deformation monitoring such as mine subsidence monitoring,surface deformation monitoring,large bridge deformation monitoring and landslide monitoring,but the identification and extraction of permanent scatterer(PS)However,the identification and extraction of permanent scatterers have been limiting the development of PSIn SAR technology.In recent years,traditional single-polarization images have been widely used in surface deformation monitoring,and for the multi-polarization data sources provided by commercial SAR satellites,the PS point density of images with different polarization methods varies greatly,and the search for the scattering mechanism with optimal polarization provides a new idea for the identification and extraction of PS points.This thesis is based on the Everest elevation measurement project supported by the National Basic Mapping Project,and uses 24-view dualpolarization ALOS-2 images for surface deformation monitoring in the Everest region,aiming to study the optimal scattering mechanism of dual-polarization channels,maximize the number of PS points,and have a clearer and more comprehensive understanding of the deformation within the Everest region,as well as in the human response to natural disasters and environmental protection.It has important practical and theoretical significance.In this thesis,the pauli decomposition and polarization base transformation are performed on the aligned ALOS-2 dual-polarized image,and the pauli parameters of different scattering mechanisms and the amplitude dispersion index(ADI)are established,and the simulated annealing(SA)algorithm is used to find the optimal polarization scattering base under the dualpolarized condition,so that the ADI of the pixel can be reduced as much as possible,and finally,the interferometric point target analysis(IPTA)technique is used to obtain the overall deformation of the large area.The results of the optimal dual-polarization(OPT)are consistent with those of the single-polarization HH deformation,which can provide a wide range of applications in the field of large-area surface deformation monitoring and disaster management.In terms of parameters,the four pauli parameters with different scattering mechanisms of the fully polarized image,while the dual-polarized image is chosen as the experimental data in this thesis,so the four pauli parameters with different scattering mechanisms are reduced to two,so the complexity of the equation establishment and the time consumed for the optimization search calculation will be reduced,thus improving the optimization search efficiency.In terms of algorithm,the improved SA algorithm is proposed,and after comparing the optimization-seeking ability of particle swarm optimization(PSO),the experimental results illustrate that the improved SA algorithm has good stability and optimization-seeking ability,and the SA process adopts different annealing rates to save the total annealing time and achieve the dual-polarization optimum by different initial temperatures and the number of stable iterations.In this thesis,the deformation monitoring results of three polarization methods are obtained by IPTA technology,the PS points of the deformation monitoring results of the SA algorithm are2.15 times and 7.63 times of the HH and HV polarization images,respectively,and the deformation points common to the HH and bipolar OPT polarization combinations are selected,and the deformation rate difference between the two polarization deformation points is calculated,and the deformation rate is estimated by using the HH and optimal polarization deformation monitoring results.Thus the mutual difference expectation and the error in the mutual difference are obtained to be about 0.203 and 1.416,respectively,indicating that the difference between OPT polarization and HH polarization deformation monitoring results is extremely small,and the PS point of OPT polarization maintains good consistency with HH and HV polarization as a whole,and finally illustrates that the variation range of the deformation rate of OPT polarization monitoring is between-45-41 mm/yr.