The problems of ITRF2008,the latest International Terrestrial Reference Frame,are pointed out and analyzed as follows:(1) ITRF is not a mm-level Terrestrial Reference Frame;(2) the origin of ITRF is neither the Earth&...The problems of ITRF2008,the latest International Terrestrial Reference Frame,are pointed out and analyzed as follows:(1) ITRF is not a mm-level Terrestrial Reference Frame;(2) the origin of ITRF is neither the Earth's center of mass (CM) nor the center of figure (CF);(3) the scale of ITRF is not a uniform system in the sense of the gravitational theory of relativity.These problems result from the linear hypothesis used in the establishment and maintenance of ITRF,which includes the linear hypothesis of the coordinates definition of the ITRF reference stations,and the seven coordinate transformation parameters (three translation parameters,three rotation parameters,and one scale parameter) when the ITRF combine solution is constructed.The linear hypothesis of the ITRF construction leads to the current terrestrial reference frame only at the cm-level,which cannot satisfy the requirements of monitoring mm-level crust movements as well as the global environment.This article points out that the construction of a mm-level Terrestrial Reference Frame is actually a leap from linear to nonlinear.Therefore,according to the main characteristics of nonlinear changes of the crust's deformation,the geocenter motion and the overall height fluctuation of the Earth,the new ITRF station coordinates definition and the new observation equations of combined solutions are constructed for the realization of a mm-level nonlinear ITRF,which can solve the problems of the current ITRF.展开更多
This paper presents an option for modern dynamic terrestrial reference system realization in Uzbekistan for user needs. An additive model is explored to predict patterns of time series and investigate means of constru...This paper presents an option for modern dynamic terrestrial reference system realization in Uzbekistan for user needs. An additive model is explored to predict patterns of time series and investigate means of constructing forecast time series models in the future. The main components(trend, periodical, and irregular) of the KIUB(DORIS) and KIT3, TASH, MADK, and MTAL(GNSS) international stations coordinate time series were investigated. It was shown that seasonal nonlinear trends occurred both in the height(U) component of all stations and the east(E) component of high mountainous stations such as MTAL and MADK. The seasonal periodical portion of the time series determined from the additive model has a complicated pattern for all sites and can be explained as both hydrological signals in the region and improvement of observational quality. Amplitudes of the best-fitting sinusoids in the North component ranged between 1.73 and 8.76 mm; the East component ranged between 0.82 and 11.92 mm; and the Up component ranged between 3.11 and 40.81 mm. Regression analysis of the irregular portion of the height component of the two techniques at the Kitab station using tropospheric parameters(pressure and temperature) was confirmed as only 57% of the stochastic portion of the time series.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.10603011)the National High Technology Research and Development Program (Grant No.2009AA12Z307)+1 种基金the Science and Technology Commission of Shanghai Municipality (Grant Nos.05QMX1462 and 08ZR1422400)the Youth Foundation of Knowledge Innovation Project of the Chinese Academy of Sciences,Shanghai Astronomical Observatory (Grant No.5120090304)
文摘The problems of ITRF2008,the latest International Terrestrial Reference Frame,are pointed out and analyzed as follows:(1) ITRF is not a mm-level Terrestrial Reference Frame;(2) the origin of ITRF is neither the Earth's center of mass (CM) nor the center of figure (CF);(3) the scale of ITRF is not a uniform system in the sense of the gravitational theory of relativity.These problems result from the linear hypothesis used in the establishment and maintenance of ITRF,which includes the linear hypothesis of the coordinates definition of the ITRF reference stations,and the seven coordinate transformation parameters (three translation parameters,three rotation parameters,and one scale parameter) when the ITRF combine solution is constructed.The linear hypothesis of the ITRF construction leads to the current terrestrial reference frame only at the cm-level,which cannot satisfy the requirements of monitoring mm-level crust movements as well as the global environment.This article points out that the construction of a mm-level Terrestrial Reference Frame is actually a leap from linear to nonlinear.Therefore,according to the main characteristics of nonlinear changes of the crust's deformation,the geocenter motion and the overall height fluctuation of the Earth,the new ITRF station coordinates definition and the new observation equations of combined solutions are constructed for the realization of a mm-level nonlinear ITRF,which can solve the problems of the current ITRF.
基金funded by the research-applied project of the Astronomical Institute of Uzbekistan (FA-A5-F014)
文摘This paper presents an option for modern dynamic terrestrial reference system realization in Uzbekistan for user needs. An additive model is explored to predict patterns of time series and investigate means of constructing forecast time series models in the future. The main components(trend, periodical, and irregular) of the KIUB(DORIS) and KIT3, TASH, MADK, and MTAL(GNSS) international stations coordinate time series were investigated. It was shown that seasonal nonlinear trends occurred both in the height(U) component of all stations and the east(E) component of high mountainous stations such as MTAL and MADK. The seasonal periodical portion of the time series determined from the additive model has a complicated pattern for all sites and can be explained as both hydrological signals in the region and improvement of observational quality. Amplitudes of the best-fitting sinusoids in the North component ranged between 1.73 and 8.76 mm; the East component ranged between 0.82 and 11.92 mm; and the Up component ranged between 3.11 and 40.81 mm. Regression analysis of the irregular portion of the height component of the two techniques at the Kitab station using tropospheric parameters(pressure and temperature) was confirmed as only 57% of the stochastic portion of the time series.
