Research On Coseismic Displacement Estimation Using A Single High-Rate GPS/BDS Receiver

Earthquake is one of the most common natural disasters on the earth and poses serious risks to human,especially large destructive earthquakes.Currently,no one can accurately predict earthquakes,but earthquake early waving(EEW),which is Considered to be a pragmatic and viable way to reduce the damage and casualties during an earthquake,relies on the accurate estimation of displacements and the capability of rapidly deletion of the first arrival wave(Pwave)as an earthquake happens.Coseismic displacement is an important parameter for seismic magnitude estimation,but Seismograph/macro seismograph will be saturated when large earthquake happened.With the development of the technology,such as high acquisition rate,large data storage capability,etc.,high-rate GNSS is proved to be a reliable tool to capture surface displacements including static offsets and dynamic motions in the near field,which does not suffer from the problems as the traditional seismic instrument does.According to above requirements,the research of this thesis are summarized as follow:1.The basic theory of GNSS positioning and the method of measuring data processing are studied.The error sources of GNSS positioning are analysed in detail and we give the solutions accordingly.We also derive the formula of least square method and semi-parametric model and analyse their advantages and disadvantages.2.Based on the theory of GNSS,we studied the theory of GNSS velocity measurement methods.The difference between three GNSS velocity measurement methods and then mathematical model of GNSS velocity measurement is constructed.the model is validated by static and real kinematic GNSS data.3.To increasing accuracy,research on GPS/BDS combination.Compare the accuracy of GPS and BDS and combined system by calculating the data.The results show that using combined system can improved observation condition and accuracy effectively.4.We can weaken some errors by mathematical models or other methods during calculation,but residual systematic bias still existed.The semi-parametric model is introduced to separate systematic bias to improve the accuracy and the model is validated by the example.