Precision analysis for Compass satellite clock prediction based on a universal clock offset model

Abstract

Prediction accuracy for satellite clock parameters directly affects the performance of satellite navigation systems and services. There are many factors which can affect the satellite clock prediction accuracy. The quality of modeling clock sequence is a very important influence factor. Only those which can best reflects onboard clock running and physical characteristics can obtain a higher accuracy of satellite clock prediction. This paper analyzed the characteristics of the Compass system clock offset sequence, and proposed a universal clock offset model. The model contains a linear term, periodic term and random term, while using the AR model for stochastic modeling. We also gave a method for determining the periodic terms and AR model parameters. The model we proposed is also capable of degradation and expansion according to the actual onboard clock feature. The paper also gave the satellite clock prediction method based on the model. Finally, we conducted an experimental analysis with real Compass data. The results show that the proposed universal model can greatly improve the prediction accuracy of the satellite clock, especially for some of the less stable satellite clock. We achieve 6 h prediction accuracy better than 2 ns, and 12 h prediction accuracy better than 5.5 ns.