IGS′92联测期间地极坐标的高频波动

本文分析了ＩＧＳ＇９２联测期间七个ＧＰＳ数据处理中心提供的极坐标序列。通过谱分析、最小二乘拟合和Ｆ检验，表明在这些序列中存在一些共同的高频波动：在Ｘ方向上具有２７．０，１６．５，１３．４和１０．４天的周期，在Ｙ方向上的波动周期约为２０．５，１５．８和１０．０天。并且每个序列与ＥＯＰ（ＩＥＲＳ）９２Ｃ０４之间都存在一个系统差。计算与分析表明，这些系统偏离的主要原因是由于在用ＧＰＳ资料解算Ｘ、Ｙ时，不同分析中心采用了不同系统的台站坐标（或者说只有部分台站采用了固定的台站坐标），从而造成这些序列所在的参考架与ＩＴＲＦ９１之间存在一个平移和旋转。最后，计算了该期间的大气角动量激发函数，可部分地解释该期间的Ｘ、Ｙ高频波动的原因。

HIGH FREQUENCY FLUCTUATIONS OF POLAR MOTION DURING IGS'92 CAMPAIGN

During IGS'92 campaign,seven PM(Polar Motion) series provided by GPS Processing Centers are analysed in this paper.Several similar high frequency fluctuations in these PM series are detected by using spectral analyses,least square adjustment and F-test, as follows:There are short periodic fluctuations of 27.0, 16.5,13.4,10.4 day in X direction,and of 20.5,15.8,10.0 day in Y direction.Their maximum amplitudes of fluctuation are 1.2 mas in X(of 27.0 day) and 0.9 mas in Y(of 10.0 day).And there are similar systematic deviations derived from the comparison of each series with EOP(IERS) 92C04,in which the systematic deviations between EOP(COM.)92P01(combined series from five analysed series)and EOP(IERS)92C04 are 2.1 mas in X and 2.7 mas in Y.Taking series EOP(SHA)92P01 as an example,it is verified that the main cause of these systematic deviations lies in that the rotation between the terrestrial reference frames of these series and ITRF91 exists.The reason,we consider,may be that the coordinates of stations are not fixed (or partly fixed only)when solving X and Y with GPS data. Finally the high frequency fluctuations of polar motion are explained to some extent by the excitation of atmosphere angular momentum.