Autonomous broadcast ephemeris improvement for GNSS using inter-satellite ranging measurements

作者：Xu, Hongliang; Wang, Jinling^*; Zhan, Xingqun

来源：Advances in Space Research, 2012, 49(6): 1034-1044.

DOI：10.1016/j.asr.2012.01.001

• Precise ephemeris
• Inter-satellite ranging
• GNSS

This paper discusses the concept of using inter-satellite ranging (ISR) measurements of the satellites of a Global Navigation Satellite System (GNSS) for autonomous broadcast ephemeris improvement. Firstly the inter-satellite ranging is modeled to obtain the clock and orbit error observables. The orbit error observable is analyzed and its observation equation is provided. Both least-squares estimation and Kalman Filter approach are proposed to estimate satellite clock errors, while solely the Kalman Filter is used to estimate the orbit errors. All these algorithms are validated using true broadcast ephemeris and precise ephemeris of GPS along with the simulated ranging noise. Based on the settings adopted in the test, the result shows that the orbit accuracy of the precise ephemeris using the proposed method is around 20-50 cm and the accuracy of the satellite clock can reach 20 cm while ranging noise is assumed to be 0.45 m (1 sigma). The User Ranging Error (URE) is improved from 1.05 m to 0.34 m, which is comparable to other sources of precise ephemeris or even better, while the proposed approach has many advantages such as compatibility and accessibility. It is also noted that the proposed method may provide useful functions in determining inter-constellation coordinate and time differences autonomously for better inter-operability and interchangeability in the multi GNSS operation era.

• 出版日期2012-3-15
• 单位上海交通大学