Currently three up-to-date Terrestrial Reference Frames(TRF) are available, the ITRF2014 from IGN, the DTRF2014 from DGFI-TUM, and JTRF2014 from JPL. All use the identical input data of space-geodetic station position...Currently three up-to-date Terrestrial Reference Frames(TRF) are available, the ITRF2014 from IGN, the DTRF2014 from DGFI-TUM, and JTRF2014 from JPL. All use the identical input data of space-geodetic station positions and Earth orientation parameters, but the concept of combining these data is fundamentally different. The IGN approach is based on the combination of technique solutions, while the DGFI is combining the normal equation systems. Both yield in reference epoch coordinates and velocities for a global set of stations. JPL uses a Kalman filter approach, realizing a TRF through weekly time series of geocentric coordinates. As the determination of the CRF is not independent of the TRF and vice versa, the choice of the TRF might impact on the CRF, Within this work we assess this effect.We find that the estimated Earth orientation parameter(EOP) from DTRF2014 agree best with those from ITRF2014, the EOP resulting from JTRF2014 show besides clear yearly signals also some artifacts linked to certain stations. The estimated source position time series however, agree with each other better than ±1 μas. When fixing EOP and station positions we can see the maximal effect of the TRF on the CRF. Here large systematics in position as well as proper motion arise. In case of ITRF2008 they can be linked to the missing data after 2008. By allowing the EOP and stations to participate in the adjustment,the agreement increases, however, systematics remain.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
地心运动会影响地球参考框架原点的准确性,是地球参考框架进行非线性维持必须考虑的因素之一,因此提出对地心运动进行多尺度的建模和预测,以实现毫米级地球参考框架的建立和维持。采用网平移法计算的地心运动、全球地球物理流体中心(glo...地心运动会影响地球参考框架原点的准确性,是地球参考框架进行非线性维持必须考虑的因素之一,因此提出对地心运动进行多尺度的建模和预测,以实现毫米级地球参考框架的建立和维持。采用网平移法计算的地心运动、全球地球物理流体中心(global geophysical fluids center,GGFC)和国际GNSS服务(international gnss service,IGS)第三次重处理(IGSR03)提供的3组地心运动数据,首先对其一致性和差异进行了分析,然后分别利用谐波模型和Diff-LSTM模型对地心运动进行了长期和短期的建模与预测,结果显示,GGFC地心运动的预测精度优于1.5 mm,而Diff-LSTM模型的地心运动预测结果在短期内优于谐波模型,当预测步长为17时,GGFC和IGSR03的地心运动预测精度均能达到甚至优于1 mm。表明地心运动的预测精度能够满足基于地球质量中心(center of mass of the total earth system,CM)的瞬时地球参考框架的建立与维持。展开更多
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
基金supported by the Deutsche Forschungsgemeinschaft(DFG), Project Nr.:HE 5937/2-1 and NO318/ 13-1supported by the European Research Council(ERC) under the ERC-2017-STG SENTIFLEX project(Grant Agreement 755617)
文摘Currently three up-to-date Terrestrial Reference Frames(TRF) are available, the ITRF2014 from IGN, the DTRF2014 from DGFI-TUM, and JTRF2014 from JPL. All use the identical input data of space-geodetic station positions and Earth orientation parameters, but the concept of combining these data is fundamentally different. The IGN approach is based on the combination of technique solutions, while the DGFI is combining the normal equation systems. Both yield in reference epoch coordinates and velocities for a global set of stations. JPL uses a Kalman filter approach, realizing a TRF through weekly time series of geocentric coordinates. As the determination of the CRF is not independent of the TRF and vice versa, the choice of the TRF might impact on the CRF, Within this work we assess this effect.We find that the estimated Earth orientation parameter(EOP) from DTRF2014 agree best with those from ITRF2014, the EOP resulting from JTRF2014 show besides clear yearly signals also some artifacts linked to certain stations. The estimated source position time series however, agree with each other better than ±1 μas. When fixing EOP and station positions we can see the maximal effect of the TRF on the CRF. Here large systematics in position as well as proper motion arise. In case of ITRF2008 they can be linked to the missing data after 2008. By allowing the EOP and stations to participate in the adjustment,the agreement increases, however, systematics remain.
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.
文摘地心运动会影响地球参考框架原点的准确性,是地球参考框架进行非线性维持必须考虑的因素之一,因此提出对地心运动进行多尺度的建模和预测,以实现毫米级地球参考框架的建立和维持。采用网平移法计算的地心运动、全球地球物理流体中心(global geophysical fluids center,GGFC)和国际GNSS服务(international gnss service,IGS)第三次重处理(IGSR03)提供的3组地心运动数据,首先对其一致性和差异进行了分析,然后分别利用谐波模型和Diff-LSTM模型对地心运动进行了长期和短期的建模与预测,结果显示,GGFC地心运动的预测精度优于1.5 mm,而Diff-LSTM模型的地心运动预测结果在短期内优于谐波模型,当预测步长为17时,GGFC和IGSR03的地心运动预测精度均能达到甚至优于1 mm。表明地心运动的预测精度能够满足基于地球质量中心(center of mass of the total earth system,CM)的瞬时地球参考框架的建立与维持。
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.
