海潮负荷地心运动对GPS坐标时间序列周期信号的影响分析

分别采用地球系统质心（center of mass of the whole earth system, CM）和固体地球质心（center of mass of the solid earth, CE）框架的海潮负荷(ocean tide loading, OTL)改正计算132个全球站的静态精密单点定位PPP坐标，分析海潮负荷引起的地心运动对GPS坐标时间序列的影响。结果表明：1）海潮负荷地心运动在水平和垂直方向上引起的坐标差异分别为0.7 mm和1.3 mm，海潮负荷地心运动对坐标时间序列的影响具有显著的区域分布特征；2）在CM-OTL和CE-OTL中，海潮负荷效应引起的周期信号明显减小，海潮负荷改正所属框架与GPS轨道所属框架的不一致将引入GPS交点年信号、14 d、9 d信号；3）利用IGS精密轨道进行PPP计算时，应采用CE框架进行海潮负荷改正。

Effect of Geocenter Motion Induced by Ocean Tide Loading on Periodic Signals of GPS Position Time Series

Using ocean tide loading(OTL) corrections computed in the center of mass of the whole earth system(CM) frame and in the center of mass of the solid earth(CE) frame, we compute PPP position time series of 132 global stations to investigate the effect of geocenter motion induced by OTL on periodic signals of GPS position time series. The result shows that: 1) The average position differences induced by OTL geocenter motion are 0.7 mm and 1.3 mm for the horizontal and vertical components, respectively, and the effect of OTL-induced geocenter motion on GPS position time series is very similar for adjacent stations. 2) In CM-OTL and CE-OTL, the periodic signal caused by the tidal load effect is significantly reduced, and the inconsistency between the frame to which the tidal load correction belongs and the frame to which the GPS track belongs will introduce the GPS nodal year signal, 14 d and 9 d signals. 3) When performing PPP using precise satellite products provided by IGS, the OTL in the CE frame should be employed.