Research On The Key Algorithm For Resolving Co-seismic Ground Displacement With High-rate GPS Single-station Data

With the increasing popularity of the high-rate GPS receiver,and the high-rate GPS can directly estimate the displacement of GPS stations,so the high-rate GPS has a broad development prospect in seismology.The duration of earthquake is very short,based on the strong correlation of tropospheric delay in short time and ambiguity fixing without jump,so this dissertation adopts a method to resolve the instantaneous ground displacement of GPS stations during earthquake depending on a time baseline positioning model using single receiver.In this dissertation,based on the time baseline model and ionosphere-free satellite single difference model using single receiver,the satellite single difference time baseline positioning observation model using single receiver is obtained,and the stochastic model is deduced.Depending on the time baseline positioning observation model using single receiver,this dissertation concludes that the satellite clock error and the cycle-slip are the main factors influencing the accuracy of the model.The satellite clock error is usually corrected by piecewise linear interpolation,sleek Lagrange interpolation and cubic spline interpolation.This dissertation aims to analyze these three interpolation methods and the experiments show that the precision of piecewise linear interpolation is the highest.Then,this dissertation discusses geometry free combination and Wubbena-Melbourne combination with dual-frequency signals,and effectiveness and limitations of the two methods verifies by experiments.According to the Baarda data snooping and LAMBDA method for integer ambiguity estimation,this dissertation develops a sequential least squares detecting and repairing cycle-slip method based on state estimation.Next,this dissertation studies the various influence factors of the new method,and the experiments are carried out using 1Hz static data and 1Hz seismic data.The experiments show that this method can effectively repair cycle-slip of more than 1 cycle in static data and seismic data.At last,after completing the satellite error correction and cycle-slip detecting and repairing,this dissertation analyzes the 5Hz high-rate static data,1Hz high-rate GPS data collected from the California Real Time Network during EI-Mayor-Cucapah earthquake occurred in Mexico's Baja California region and 50Hz high-rate GPS data collected from Lushan earthquake.The experimental results show that the root mean square errors of ground displacement of N,E and U were 3.1mm,3.3mm,8.5mm and the ground displacement distribution is normal distribution for static data.For 1Hz high-rate GPS data during EI-Mayor-Cucapah earthquake,the ground displacement resolved during the earthquake by the time baseline positioning model using single receiver is not affected by the reference station compared with the double difference solution of SOPAC(Scripps Orbit and Permanent Array Center),so the dynamic displacement information is more accurate and more consistent with the motion of the GPS stations during the earthquake.The results of maximum amplitude of the stations resolved during the LuShan earthquake by the time baseline positioning model using single receiver are only 2mm from the previous studies.The results of these three experiments verify the correctness and reliability of the satellite single difference time baseline positioning observation model using single receiver.