Time series of Earth rotation parameters were estimated from range data measured by the satellite laser ranging technique to the Laser Geodynamics Satellites（LAGEOS）-1/2 through 2005 to 2010 using the dynamic method...Time series of Earth rotation parameters were estimated from range data measured by the satellite laser ranging technique to the Laser Geodynamics Satellites（LAGEOS）-1/2 through 2005 to 2010 using the dynamic method. Compared with Earth orientation parameter（EOP）C04, released by the International Earth Rotation and Reference Systems Service, the root mean square errors for the measured X and Y of polar motion（PM） and length of day（LOD）were 0.24 and 0.25 milliarcseconds（mas）, and 0.068 milliseconds（ms）, respectively.Compared with ILRSA EOP, the X and Y of PM and LOD were 0.27 and 0.30 mas, and 0.054 ms, respectively. The time series were analyzed using the wavelet transformation and least squares methods. Wavelet analysis showed obvious seasonal and interannual variations of LOD, and both annual and Chandler variations of PM; however, the annual variation could not be distinguished from the Chandler variation because the two frequencies were very close. The trends and periodic variations of LOD and PM were obtained in the least squares sense, and PM showed semi-annual, annual, and Chandler periods.Semi-annual, annual, and quasi-biennial cycles for LOD were also detected. The trend rates of PM in the X and Y directions were 3.17 and 1.60 mas per year, respectively, and the North Pole moved to 26.8E relative to the crust during 2005—2010. The trend rate of the LOD change was 0.028 ms per year.展开更多
In this study, a method for determination of stations coordinates, Earth rotation parameters and gravity field coefficients in one solution from SLR data from LAGEOS and LEO is presented. A new software package based ...In this study, a method for determination of stations coordinates, Earth rotation parameters and gravity field coefficients in one solution from SLR data from LAGEOS and LEO is presented. A new software package based on the presented method has been developed. All recommendations from IERS Con- ventions 2010 have been included. In addition, some other perturbations and loading effects are taken into account： atmospheric tides, non-tidal atmosphere and ocean variability, albedo and non-tidal at- mospheric pressure loading. Results of different solutions with the use of only LAGEOS data or LAGEOS plus LEO satellites data are presented. Pole coordinates obtained from both solutions show comparable accuracy relative to IERS 08 C04 solution. As for UT1 corrections in terms of Length-of-Day an additional improvement in accuracy is found： 1.0 ms for LAGEOS and 0.2 ms for the combined LAGEOS ＋ LEO solution. Time series of the estimated degree-2 gravity field coefficients show a very good agreement with results of the Center of Space Research （Austin/USA）. As a final remark, some future mandatory steps are outlined.展开更多
基金supported by the National Natural Science Foundation of China(41374009)International Science and Technology Cooperation Program of China(2009DFB00130)+2 种基金Public Benefit Scientific Research Project of China(201412001)Shandong Natural Science Foundation of China(ZR2013DM009)the SDUST Research Fund(2014TDJH1010)
文摘Time series of Earth rotation parameters were estimated from range data measured by the satellite laser ranging technique to the Laser Geodynamics Satellites（LAGEOS）-1/2 through 2005 to 2010 using the dynamic method. Compared with Earth orientation parameter（EOP）C04, released by the International Earth Rotation and Reference Systems Service, the root mean square errors for the measured X and Y of polar motion（PM） and length of day（LOD）were 0.24 and 0.25 milliarcseconds（mas）, and 0.068 milliseconds（ms）, respectively.Compared with ILRSA EOP, the X and Y of PM and LOD were 0.27 and 0.30 mas, and 0.054 ms, respectively. The time series were analyzed using the wavelet transformation and least squares methods. Wavelet analysis showed obvious seasonal and interannual variations of LOD, and both annual and Chandler variations of PM; however, the annual variation could not be distinguished from the Chandler variation because the two frequencies were very close. The trends and periodic variations of LOD and PM were obtained in the least squares sense, and PM showed semi-annual, annual, and Chandler periods.Semi-annual, annual, and quasi-biennial cycles for LOD were also detected. The trend rates of PM in the X and Y directions were 3.17 and 1.60 mas per year, respectively, and the North Pole moved to 26.8E relative to the crust during 2005—2010. The trend rate of the LOD change was 0.028 ms per year.
文摘In this study, a method for determination of stations coordinates, Earth rotation parameters and gravity field coefficients in one solution from SLR data from LAGEOS and LEO is presented. A new software package based on the presented method has been developed. All recommendations from IERS Con- ventions 2010 have been included. In addition, some other perturbations and loading effects are taken into account： atmospheric tides, non-tidal atmosphere and ocean variability, albedo and non-tidal at- mospheric pressure loading. Results of different solutions with the use of only LAGEOS data or LAGEOS plus LEO satellites data are presented. Pole coordinates obtained from both solutions show comparable accuracy relative to IERS 08 C04 solution. As for UT1 corrections in terms of Length-of-Day an additional improvement in accuracy is found： 1.0 ms for LAGEOS and 0.2 ms for the combined LAGEOS ＋ LEO solution. Time series of the estimated degree-2 gravity field coefficients show a very good agreement with results of the Center of Space Research （Austin/USA）. As a final remark, some future mandatory steps are outlined.
