Study Of Time-frequency Analysis Of GPS Coordinate Time Series In Antarctica

With the observation data of IGS accumulated gradually, the research about the GPS coordinates time series has become a hot spot in geodesy. The research for IGS reference stations coordinate time series in Antarctica can deepen our understanding to the natural environment and the plate tectonics.The study mainly included the analysis of noise characteristics, cycle characteristics and the changing rule of reference stations point. Firstly, it analyzed the data quality of 9 IGS reference stations coordinate time series in Antarctica and found the data of part of the stations were seriously lack. Corresponding solution strategy for the problem of data mutation, discontinuity and step were put forward, getting the data that meeting the requirements for following analysis. Secondly, it analyzed the noise characteristics of GPS coordinate time series in Antarctica using HVT and CA method. It verified that there is white noise and color noise in the GPS coordinate time series. The level of U component noise is significantly higher than N component and E component. Some seasonal natural factors such as tides, atmospheric pressure were obviously correlative with the GPS coordinate time series. Then, it analyzed the cycle characteristics using power spectral analysis, wavelet analysis, and empirical mode decomposition. The three methods all showed that there was a annual cycle conspicuously on the U component of GPS coordinate time series. There was a Semi-annual cycle on Part of the stations. In addition, it compared the difference between the hard and soft threshold noise reduction. Finally, it verified the effectiveness of the method that calculated the movement speed in horizontal and vertical using Linear Fitting and EMD; It analyzed the stability according to the movement speed of the 9 reference stations, and verified that the Antarctic continent was moving slowly to South America. Combined with the speed of baseline, the author found that the Antarctic plate was relatively stable, and the geological condition in West Antarctic was more active than East Antarctic. In addition, it analyzed the influencing factors that lead the IGS reference stations to change.