Time synchronization between ground and satellites is a key technology for satellite navigation system. With dual-channel satellite, a method called Two-Way Common-View (TWCV) satellite time transfer for Compass system is proposed in recent study.
The title of the paper related to the study is "The method and experiment analysis of two-way common-view satellite time transfer for compass system", which is written by LIU Li from Beijing Satellite Navigation Center and published in SCIENCE CHINA Physics, Mechanics & Astronomy 2015, 58. The researcher combines both characteristics of satellite common-view and two-way satellite-ground time transfer to improve the precision of time transfer.
The principle of TWCV is that it can completely eliminate the influence of common errors, such as satellite clock offset, ephemeris errors, troposphere delay and station coordinates errors by satellite-ground two-way pseudo-range differencing and two stations common-view differencing. At the same time, ionosphere delay related to signal frequency is also weakened significantly. So the precision of time transfer is improved much more greatly than before.
In this paper, the basic principle is introduced in detail, the effect of major errors is analyzed and the practical calculation model in the Earth-fixed coordinate system for this new method is provided. Finally, experiment analysis is conducted with actual Compass observing data. The results show that the deviation and the stability of the satellite dual channel can be better than 0.1 ns, and the accuracy of the two-way common-view satellite time transfer can achieve 0.4 ns. All these results have verified the correctness of this TWCV method and model. In addition, we compare this TWCV satellite time transfer with the independent C-band TWSTFT (Two-Way Satellite Time and Frequency Transfer). It shows that the result of the TWCV satellite time transfer is in accordance with the C-band TWSTFT result, which further suggests that the TWCV method is a remote high precision time transfer technique.
The research results in this paper are very important references for the development and application of Compass satellite navigation system.
This research was funded by the National Natural Science Foundation, China (No.41174027) and National 863 Project, China (No.2013AA122402)
See the article: L. Liu, G. F. Tang, C. H. Han, X. Shi, R. Guo, L. F. Zhu. "The method and experiment analysis of two-way common-view satellite time transfer for compass system", Sci China-Phys Mech Astron. (2015) 58(8): 089502. doi: 10.1007/s11433-015-5679-2