BDS/GPS星载原子钟的短期钟差预报模型研究

Study on the Prediction Model of Short-term Clock Difference for the Atomic Clock Onboard BDS/GPS Satellite

针对BDS(BeiDou Navigation Satellite System)/GPS(Global Positioning System)星载原子钟特性和卫星钟差预报模型研究中存在的若干问题,在介绍4种单一模型(多项式模型(QR)、灰色模型(GM)、时间序列模型(ARMA)和广义回归神经网络模型(GRNN))的基础上,引入了经典权组合模型(CM)和修正经典权组合模型(Modified CM).利用武汉大学卫星导航定位技术研究中心的卫星精密钟差产品对BDS/GPS星载原子钟的短期钟差预报模型进行研究,并对比了不同卫星钟和不同模型的预报效果.试验结果表明:单一模型对于BDS卫星钟(C04(GEO Rb)、C07(IGSO Rb)、C14(MEO Rb))的钟差预报精度跳跃性很大;而对于GPS卫星钟(G04(Block IIA Rb)、G09(Block IIA Cs)、G16(Block IIR Rb)、G31(Block II-M Rb)、G27(Block IIF Rb)、G24(Block IIF Cs))的预报精度变化比较平稳;同一种预报模型应用在不同类型的卫星钟序列中,预报精度差异较大.然而,修正经典权组合模型在保证预报可靠性的前提下提高了预报精度,在一定程度上优于其他模型.

According to the characteristics of BDS/GPS satellite clock and satellite clock error problems of prediction model, this paper introduces 4 kinds of single model （polynomial model （QR）, grey model （GM）, time series model （ARMA）, and generalized regression neural network model （GRNN）） on the basis of classical models, and the modified classical weight combination model is deduced. The satellite clock precision products of the GNSS （Global navigation satellite system） research center of Wuhan University are used to study the short-term satellite atomic clock error prediction model of BDS/GPS, to compare different satellite clocks and predicted effects of different models. The test results show that the single model for the BDS satellite clock （C04 （GEO Rb）, C07 （IGSO Rb）, and C14 （MEO Rb）） has a large jump of prediction accuracy; and for the GPS satellite clock G04 （（Block IIA Rb）, G09 （Block IIA Cs）, G16 （Block IIR Rb）, G31 （Block II-M Rb）, G27 （Block IIF Rb）, and G24 （Block IIF Cs）） the forecast accuracy change is relatively stable; when the same prediction model is used in the satellite clock sequence with different types, the prediction accuracy is quite different. However, the correction of the classical weighted combination model improves the prediction accuracy under the premise of ensuring the reliability of prediction, and is superior to other models to some extent.