The orientation of the Earth is defined by Earth orientation parameters that are measured by space geodetic techniques. The results provided by these techniques differ from each other. The method presented here combines these results in order to get a representative solution of the Earth orientation parameters. Other products of the method are improved coordinates and velocities of collocations stations distributed on six major and two minor tectonic plates. The fact that the stations lie on their plates gives us possibility to describe movements of these plates during our data interval. All new results are compared with the ones published by ITRF 2005 and presented hereafter., Vojtěch Štefka., and Obsahuje bibliografii
The combination method of results of different space geodetic techniques gives two kinds of products. On the one hand, the Earth orientation parameters (EOP) that define the orientation of the Earth in space and, on the other, the coordinates of collocation stations by them the ITRF is realized. Obtained results are based on the method developed by authors, so called “non-rigorous” combination of the data. Approximately eight-year data was successively processed in order to obtain solutions of both products, which were then compared with the results given in ITRF 2005 solution., Vojtěch Štefka, Jan Kostelecký, and Ivan Pešek., and Obsahuje bibliografii
The orientation of the Earth in space is measured by space geodetic techniques. Each technique has its weaknesses so the best way how to get a representative solution of Earth orientation parameters is to combine all of them together using some appropriate method. There are basically two approaches, the rigorous and non-rigorous one. The method used in this paper belongs to the second category. Since 1999, when the authors Kostelecký and Pešek put basis of the combination method, the method has been modified and improved. The particular improvements are described hereafter and recent results are presented. These results of collocation station velocities are compared with the velocities published by ITRF 2005 and NUVEL-1A. The mean values of differences are 2.7 mm/y and 5.9 mm/y, respectively., Vojtěch Štefka, Ivan Pešek, Jan Vondrák and Jan Kostelecký., and Obsahuje bibliografii
Four space geodesy techniques, namely VLBI, GPS, SLR and Doris, produce Earth orientation parameters (EOP) and station coordinates independently of each other. A method to combine them in a non-rigorous way (as described elsewhere) was modified by implementing Vondrak’s smoothing. It replaces a simple constraint to tie EOP at adjacent epochs by a more general expression defining smoothness of the resulting curves. This gives the method better stability of derived EOP. The new method was tested on GPS, VLBI and SLR data covering a one-year interval. The results were compared with the results of the original method and with the IERS c04 solution. The former indicates the effect of modification while the latter shows differences of this particular solution from the official IERS series, Vojtěch Štefka and Ivan Pešek., and Obsahuje bibliografické odkazy
The combination method of results of different space geodetic techniques was recently improved and used to process approximately eight-year data obtained by three space geodetic techniques. The results are compared with the results obtained by the old approach of this method and finally with the solutions of ITRF 2005., Vojtěch Štefka., and Obsahuje bibliografii