Analyses on the Time Series of the Radio Telescope Coordinates of the IVS-R1 and –R4 Sessions 

E. Tanir1, V. Tornatore2, K. Teke3,4

1Dept. of Geodesy and Photogrammetry Engineering, Karadeniz Technical University, Turkey
2Dept. of Hydraulics, Environmental, Road Infrastracture, Remote Sensing Engineering, Politecnico di Milano, Italy
3Institute of Geodesy and Geophysics, Vienna University of Technology, Austria
4Dept. of Geodesy and Photogrammetry Engineering, Hacettepe University, Turkey

Poster 

In this study, we investigate the coordinate time series of the radio telescopes which regularly takes part for IVS-R1 and –R4 Sessions. To single out some stochastic properties of the series, autocorrelation coefficients are investigated by plotting the correlograms of each time series of coordinates. By means of analyzing the data we determine the deterministic parts of the series such as trend (velocity vectors) due to e.g. plate tectonics, and as annual and semiannual variations due to e.g. the un-modeled parts of the atmosphere, and as other cyclic variations due to some other physical causes e.g. thermal deformation of the antenna. The trends of the coordinate time series are estimated by least square (LS), fitting the coefficients of a linear regression function. The annual and semiannual variations of the series if they exist are determined by estimating the amplitudes of Fourier series with LS fit. The estimates of linear trends and amplitude of a periodic function are tested if they are statistically significant.

To find groups of series with common trends we have started to investigate also another approach that make use of co-integration model,  to establish if the annual behavior of the series can be considered similar every year not only from a simple inspection of the data but also from a statistical point of view.