地心运动会影响地球参考框架原点的准确性,是地球参考框架进行非线性维持必须考虑的因素之一,因此提出对地心运动进行多尺度的建模和预测,以实现毫米级地球参考框架的建立和维持.采用网平移法计算的地心运动、全球地球物理流体中心(global geophysical fluids center,GGFC)和国际 GNSS 服务(international gnss service,IGS)第三次重处理(IGSR03)提供的3组地心运动数据,首先对其一致性和差异进行了分析,然后分别利用谐波模型和Diff-LSTM模型对地心运动进行了长期和短期的建模与预测,结果显示,GGFC地心运动的预测精度优于1.5 mm,而Diff-LSTM模型的地心运动预测结果在短期内优于谐波模型,当预测步长为17时,GGFC和IGSR03的地心运动预测精度均能达到甚至优于1 mm.表明地心运动的预测精度能够满足基于地球质量中心(center of mass of the total earth system,CM)的瞬时地球参考框架的建立与维持.
Analysis and prediction of geocentric motion based on coordinate time series
Geocentric motion affects the accuracy of the origin of the earth reference frame,which is one of the necessary factors that must be considered in the nonlinear maintenance of the terrestrial reference frame.Therefore,this paper proposes multi-scale modeling and prediction of geocentric motion to achieve the goal of establishing and maintaining a millimeter-scale terrestrial reference frame.The consistency and difference among the three groups of geocentric motion data calculated by the network shift approach,the Global Geophysical Fluid Center(GGFC)and the third reprocessing of the IGS(IGSR03)are analyzed.Then the harmonic model and Diff-LSTM model were proposed for the long-term and short-term modeling and prediction,respectively.The results showed that the prediction accuracy of the GGFC geocentric motion was better than 1.5 mm,while the prediction results of the Diff-LSTM model for geocentric motion were better than the harmonic model in the short term.The prediction accuracy of both GGFC and IGSR03 can be better than 1 mm when the predictive time length is 17,which indicates that the prediction accuracy of geocentric motion can fully meet the requirements for establishing and maintaining a center of mass-based instantaneous earth reference frame.
terrestrial reference framegeocentric motion predictioncoordinate time seriesharmonic modelDiff-LSTM model
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