改进的非组合精密单点定位模型(MPPP)与实时授时研究

Study on Model and Real-Time Timing Based on Modified Uncombined Precise Point Positioning(MPPP)

【目的】基于精密单点定位(Precise Point Positioning,PPP)的时间传递技术因其高精度、广覆盖而成为GNSS时间传递中的优势性方法。然而,实践过程中发现接收机码偏差天内短时变化是影响接收机钟差估值精准度的主要偏差之一。【方法】因此,本文提出了一种改进的非组合精密单点定位(Modified Precise Point Positioning,MPPP)模型,将接收机码偏差作为时变参数估计,并基于模拟与实测数据进行了方法验证。【结果】结果表明:同等条件下,MPPP授时精度可达0.1~1ns,相较于PPP精度提升30%以上,【结论】可有效克服接收机码偏差变化对实时授时的影响。

[Objective]Time transfer technology based on precise point positioning(PPP)is the dominant method in GNSS time transfer because of its high precision and wide coverage.However,it is found in practice that the short-time variation of receiver code biases(RCBs)within a day is one of the main deviations that affect the accuracy of receiver clock offset estimation.[Methods]Therefore,a modified precise point positioning model(MPPP)is proposed in this paper,in which the RCBs are estimated as time-varying parameters,and the method is verified based on simulated and measured data.[Results]The results show that the timing accuracy of MPPP can reach 0.1~1ns,and the accuracy can be improved by more than 30%compared with PPP under the same conditions,[Conclusions]which can effectively overcome the influence of RCB changes on real-time timing.