一种卫星钟自相关的实时钟差预报算法

针对实时精密单点定位(RT-PPP)中实时数据流存在中断、延迟等问题,该文构建了顾及卫星钟自相关的随机模型,提出了一种基于方差分量估计的自适应卡尔曼滤波钟差超短期/短期预报算法,评估了连续27d实测法国空间研究中心(CNES)实时数据流CLK93产品完整率和精度水平,利用哈达玛方差对比分析了该实时产品与德国地学研究中心(GFZ)事后GBM产品的频率稳定性。利用本文算法与传统卡尔曼算法对两类产品进行预报,结果显示:CLK93产品BDS系统(C)、GPS系统(G)、GLONASS系统(R)、Galileo系统(E)30s和1min预报精度分别平均提升了8.50%、8.44%、7.20%、6.96%;GBM产品相应4个系统12h和24h预报精度分别平均提升了3.14%、3.53%、0.96%、10.01%。

A real-time clock offset prediction algorithm based on satellite clock offset autocorrelation

For the problems of interruption and delay of real-time data streams in real time precise point positioning(RT-PPP),this paper constructed a stochastic model that took into account satellite clock offset autocorrelation,and proposed an adaptive Kalman filter algorithm based on variance component estimation for the ultra-short-term/short-term clock offset prediction.Considering the realtime satellite clock offset estimation,or the ultra-short or short term clock offset prediction having been required by the prosperity of real-time multi-GNSS precision single-point positioning(PPP)technique,a new adaptive Kalman filter was proposed to perform the prediction of the multi-system real-time clock offset.The noise level of the dynamic model was adjusted online based on the method of the variance component estimation and the time correlation of clock offset was also considered.The integrity rate and the accuracy level of real-time data stream CLK93 products of Centre National d’Etudes Spatiales(CNES)of 27consecutive days were assessed.The frequency stability of the real-time products and the corresponding final GBM products of the Geo Forschungs Zentrum(GFZ)were anlysised by using Hadamard variance.The comparison results aomong the prediction with the new model and the traditional Kalman model showed that:for the 30sand 1minutes predictions of CLK93products,an improvement for the new model over the traditional mode with average increasing rates was 8.50%(BDS),8.44%(GPS),7.20%(GLONASS),and 6.96%(Galileo)respectively;For the 12hours and 24hours predictions of GBM products,an improvement for the new model over the traditional mode with average increasing rates was 3.14%(BDS),3.53%(GPS),0.96%(GLONASS),and 10.01%(Galileo)respectively.