预报模型及建模序列长度对钟差短期预报精度影响研究

Research on the Influence of Prediction Model and Modeling Sequence Length on Short-term Prediction Accuracy of Clock Bias

针对全球定位系统(Global Positioning System,GPS)星载原子钟在钟差预报时与不同模型的适应度不同的问题,采用二次多项式(Quadratic Polynomial,QP)模型、灰色(Grey Model,GM(1,1))模型和灰色+自回归(GM(1,1)+Autoregressive,GM(1,1)+AR)模型对不同类型原子钟的钟差进行预报,着重分析不同类型原子钟的预报精度、不同长度钟差序列建模预报效果以及钟差序列波动对预报结果的影响。实验结果表明:(1)钟差预报精度与建模序列长度有一定关系,二次多项式模型受影响最大,灰色+自回归模型受影响最小;(2)不同卫星原子钟在不同预报模型下最佳建模序列长度不同,铷钟受建模序列长度的影响小于铯钟;(3)二次多项式模型对铯钟预报效果较差,对铷钟预报效果可与灰色模型和灰色+自回归模型相当;(4)钟差序列波动时,建模预报精度降低,不同模型的预报结果受钟差波动幅度大小的影响不同。

Aiming at the problem that different types of GPS space-borne atomic clock shave different adaptability to different prediction models in clock difference prediction,QP model,GM(1,1)model and GM(1,1)+AR model are used to predict the clock bias of different types of atomic clocks.The analysis focuses on the prediction accuracy of different types of atomic clocks,the effect of clock bias series with different lengths and the effect of clock sequence fluctuations on model establishing and forecasting.The results show that the accuracy of the clock bias prediction has a certain relationship with the length of the modeling series.The QP model is most affected,and the GM(1,1)+AR model is least affected.The optimal modeling sequence length for different types of atomic clocks is different under different prediction models.The rubidium clock is less affected by the length of the modeling series than the cesium clock.QP model has poor prediction effect on cesium clock,and the prediction effect on rubidium clock is comparable to GM(1,1)model and GM(1,1)+AR model.When the clock bias series fluctuates,the accuracy of modeling prediction decreases,and the prediction results of different models are affected differently by the amplitude of the clock difference fluctuation.