基于多头注意力机制的极移短期预测方法研究

Research on Short-Term Polar Motion Prediction Method Based on Multi-Head Attention Mechanism

  • 摘要: 极移数据的解算存在时间滞后,难以满足卫星定轨、深空探测等空间工程的需求。本文提出一种融合有效角动量( Effective Angular Momentum,EAM)与极移时序数据的短期预测方法。首先,通过赋权处理、量纲归一化等对EAM数据进行预处理,获得与极移数据时空分辨率一致的标准序列;其次,通过采用灰色关联度分析,发现EAM-z分量对极移X、Y方向均存在显著关联性;构建基于多头注意力机制的多变量输入-单变量输出预测模型,以EAM的x、y、z分量数据及极移历史数据为特征,实现30天跨度的极移预测。采用滑动窗口策略每7天更新预测数据,共计58期预测实验。结果表明:相较于经典LS+AR模型,多头注意力机制模型在超短期内的平均绝对误差相对较高,但约第10天后预测区间表现出显著优势,预测误差降低。该研究提出的多头注意力机制模型可有效提取EAM与极移历史数据特征用于短期预测,为后续极移预测研究提供了实用参考。

     

    Abstract: Objectives: There is a time lag in the calculation of polar motion data, which is difficult to meet the needs of space engineering such as satellite orbit determination and deep space exploration. Methods: A short-term forecasting method combining Effective Angular Momentum (EAM) and polar motion timing data is proposed. Firstly, the EAM data is preprocessed by weight processing, dimension normalization, etc., and the standard sequence consistent with the spatiotemporal resolution of the polar motion data is obtained. Secondly, grey correlation analysis is used to reveal that the EAM-z component has significant coupling effect on the X and Y directions of the polar motion. Finally, a multi-variable input-univariate output prediction model based on multi-head attention mechanism was constructed, which was characterized by x, y, z component data of EAM and historical data of polar motion to achieve 30-day span of polar motion prediction. The sliding window strategy was used to update the prediction data every 7 days, and a total of 58 prediction experiments were conducted. Results: The results show that compared with the classical LS+AR model, the average absolute error of this model is relatively high in the ultra-short term, but the prediction interval shows a significant advantage and the prediction error decreases after about the 10th day. Conclusions: The multi-head attention mechanism model proposed in this paper can effectively extract the features of EAM and polar motion historical data for short-term prediction, providing a practical reference for subsequent polar motion prediction research.

     

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