Print LIU Ya-qiong1,2,3, YANG Xu-hai1,2
(1. National Time Service Center, Chinese Academy of Sciences, Xi’an 710600, China;
2. Key Laboratory of Precision Navigation and Timing Technology, Chinese Academy of Sciences, Xi’an 710600, China;
3. Graduate University of Chinese Academy of Sciences, Beijing 100039, China)
Abstract: The inter-satellite link (ISL) is one of key techniques in the autonomous operation of satellite navigation system. This article mainly describes the mode of GPS ISL and focuses on the simulation method of the GPS ISL data. The data from GPS precise ephemeris published by IGS is densified to a time interval of 1 s, by using Chebyshev polynomial fitting method. First, the distance between two satellites at the time of signal receiving is set as the initial value. Then the moment of signal transmitting for the transmitting satellite is calculated iteratively. Therefore the pseudo-range observation between two satellites can be obtained. Coupled with the constraint conditions (e.g. noise, clock offsets), the simulated inter-satellite link data are obtained finally.
Key words: inter-satellite link; TDMA(time division multiple access); satellite navigation