Analysis Of Signal And Noise In GPS Coordinate Time Series

The absolute accuracy of the high-precision GPS station coordinate time series has reached the millimeter level,which makes GPS observation technology not only real-time monitoring of the surface instantaneous deformation caused by crust intensely motion,but also to monitor the peristaltic micro-deformation of the surface.At present,GPS has become the best technical means for continuous,dynamic and real-time observation of surface deformation.Based on this background,in this paper,the GPS coordinate time series is used as the research object.The characteristics of the trend term,seasonal amplitude and phase,noise type and other parameters of GPS coordinate time series are discussed.The difference of the characteristic parameters caused by analysis method,the effects of characteristic parameters caused by common mode error,and analyzes what causes seasonal changes of GPS coordinate time series.Around the above research,the main research work and research results of this paper mainly include the following contents:(1)On the basis of introducing the basic principle,solution strategy and method and data processing flow of GPS data processing,this paper describes the conversion relationship between the commonly used coordinate system and the coordinate system in GAMIT / GLOBK software.(2)In this paper,we regard The Chinese inland Hai yuan fault,Liu pan mountains fault and the western Qin ling mountains fault area(the text referred to as A region),the southern California San Francisco Bay area(referred to as B area)as the research area and study about 130 GPS station coordinate time series' s characteristic parameters.The results show that there are no significant differences in the characteristic parameters of the 37 GPS station time series in the A region,and the trend items of some GPS stations in the B region are different on both sides of the fault,Indicating that the crustal movement on both sides of the current regional fault is still active.(3)The difference of GPS coordinate time series under different reference frames is studied for the selected area.The results show that the level trend(N,E direction)of the GPS coordinate time series under different reference frames is different,while the vertical(U direction)trend item,the seasonal variation of each direction sequence is almost unaffected by the reference frame.(4)To compare the all characteristic parameters of the GPS coordinate time series obtained by the harmonic model and EMD,the results shows that for most GPS stations the trend parameters are basically same,for some individual stations the inconsistency is likely to be affected by the seasonal fluctuations.But the station season items and the residual of the time series obtained by two methods are slightly different.It is found that the seasonal term of the station acquired by EMD contains the main period items in the original sequence,and the seasonal level of noise is much lower than that of the original sequence,and the period of the harmonic model only contains the annual and semiannual periods.(5)In this paper,we explore the effects of surface load and regional GPS network common mode error on GPS station time series.Compared with the change of GPS station time series parameters before and after the surface load correction,it is found that the trend of each direction of the station before and after the surface load correction is small and negligible,but the amplitude and noise type of the station period are different Variety.And the common mode error of the regional network has the influence on the characteristic parameters of the station.The amplitude and phase of the GPS station time series show the local consistency,and the filter is discrete and the filtered residual time series the standard deviation is obviously smaller than the standard deviation of the pre-filter residual sequence,and the velocity field in the horizontal reverse direction of the filter is obviously different in the direction of motion.