WGS84与ITRS基准转换参数估计及长期演化特性分析
Datum Transformation Parameters Estimation and Longterm Evolution Analysis of WGS84 and ITRS
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摘要: 针对在轨运行的GPS卫星,利用由NGA提供的WGS84框架下精密星历以及IGS提供的ITRS框架下的精密星历,采用7参数布尔沙模型,并结合不同卫星的星载原子钟的稳定性,在最小二乘准则下求取WGS84和ITRS之间的转换参数。在此基础上,为了得到较长时间尺度上转换参数的演化特性,首先采用EMD算法进行去噪,以使得数据更能反映参数变化的本质特性,然后在消除趋势项的基础上,对转换参数的时间序列进行谱分析,以探索其周期特性。利用NGA和IGS提供的2009-01-01~2012-06-30共1306d的精密星历,求取每天一组的坐标转换参数,分析其长期演化特性后发现:3个平移参数分别具有345d,690d和345d的周期项,3个旋转参数分别具有459d,172d和459d的周期项,尺度参数则不具有明显的周期项。Abstract: For in-orbit GPS satellites，we adopted the NUA precise ephemeris in WUS84 from NGA and ITRS from IGS，using the severrparameter Bursa model combined with different satellite-borne atomic clock stabilities at the same time to transform the parameters between WGS84 and ITRS using the least squares criterion.We eliminated the trend term based on the time sequence of the transformation parameters and at last we used spectral analysis to explore its cyclical nature. We use NGA and IGS precise ephemeris，from January 1，2009 to J une 2012，a total of 1 306 d，collecting every coordinate transform parameter to analyze long-term evolution characteristics:three translational the parameters have the 345 d，690 d and 345 d periodic terms，while three rotation parameters，with the 459 d，172 d and 459 d cycle item scale parameter respectively，are found not to be not periodic terms.
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