The strategy used in the ITRF2008, the site distribution, ITRF2008 parameters accuracy and the improvement relative to ITRF2005 are introduced. IERS released ITRF2008 on May 31, 2010 and it is refined versions of the International Terrestrial Reference Frame based on four space geodetic techniques, VLBI, SLR, GPS and DORIS. The scale agreement between ITRF2008 and ITRF2005 solutions at epoch 2005.0 is estimated to be 1.05 ± 0. 13 ppb and 0.049 ± 0.010 ppb/a respectively. The ITRF2008 orientation (at epoch 2005.0) and its rate are aligned to the ITRF2005. The differences of the origin components from ITRF2008 to ITRF2005 at epoch 2005.0 are; - 0.5, - 0.9 and - 4.7 mm along the X, Y and Z axis respectively. The differences of Y and Z translation rate between these two frames are zero, the X translation rate is 0.3 mm/a. The formal error of these parameters are estimated to be 0.2 mm and 0.2 mm/a, respectively. The ITRF2008 origin accuracy over SLR observation period based on its agreement with ITRF2005 is considered to be less than 1 cm. ITRF2008 scale accuracy, considering the scale consistency between VLBI and SLR, within a common observation time span of two technologies is less than 1.2 ppb (8mm at the equator).%介绍ITRF2008采用的策略,所用站点的分布,各项转换参数的精度以及相对于ITRF2005的改进.ITRF2008是基于4个空间大地测量技术(VLBI,SLR,GPS和DORIS)重新处理解的国际地球参考框架精化版本.ITRF2008与ITRF2005这两种技术解的尺度符合度在历元2005.0为1.05±0.13 ppb和0.049±0.010 ppb/a.ITRF2008定向(在历元2005.0)和速度与ITRF2005一致.ITRF2008与ITRF2005的原点在历元2005.0沿X、Y和Z轴的差异分别为:-0.5、-0.9和-4.7 mm.两框架之间的Y和Z平移速率差为零,X平移速度0.3 mm/a.这些参数的估计误差分别为0.2 mm和0.2 mm/a.ITRF2008原点的精度在SLR观测时间段内在1 cm以内.ITRF2008尺度的精度在VLBI和SLR两种技术的共同观测时间段内在1.2 ppb以内.
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