Time Series Analysis For APREF GPS Sites Coordinates

Continuous GPS (Global Positioning System) has become one of the major techniques for geodesy technology, GPS time series contain not only the tectonic deformation signals, but also the non-tectonic deformation signals. Before 2002, because of the lack of sufficient GPS observations and the other geophysical data to invert the displacements of the sites, the noise characteristics of the GPS time series and the non-tectonic deformation characteristics cannot be systematically studied. With the development of geodesy technology and especially the accumulation of GPS observations, there are enough GPS data to study the GPS time series. Main contents and contributions of this paper are as follows:1)Bernese software had been used to analyze a part of APREF(Asia-Pacific Reference Frame) stations dates, the internal accuracy is better than 2mm.2)Spectral analysis method was used to process the time series of coordinates for selected New Zealand sites. The results show that the annual periodicity shown in the time series of most sites in the vertical direction and some in the horizontal direction.3)The noise characteristics of time series had been assessed using Maximum Likelihood Method(MLE), the results show that the noise could be best described by Fn+wh?Pl+wh and Fn+rw+wh combinations over New Zealand.4) The results show that the accuracy of estimated rate under white noise assumption was significantly worse than the colored noise assumption.5) With the help of the wavelet coherence, we found that the correlation between surface mass redistribution time series and GPS time series is not strong in horizontal direction, and that shows strong regional features. However, there was strong correlation of the surface mass redistribution time series and GPS coordinate time series on the 1 year frequency in the vertical direction, Which indicate that the surface mass could partially be used to explain the GPS time series of tectonic cycle characteristics, but the correlation between different surface mass redistribution and GPS time series was not the same.