Applications and Prospects for Autonomous Navigation Technology in a Satellite Navigation System

Autonomous constellation navigation is an important means for improving the continuous delivery of services by satellite navigation systems when experiencing conditions such as major disasters and failure of ground operation control facilities. It is also a useful supplement to the normal operation and control mode, which can reduce dependence on the ground facilities while lowering operating costs. This article introduces a method for evaluating experiments on the autonomous constellation navigation of satellite navigation systems. These experiments were based on 12 days of BDS-3 satellite observation data. The evaluation results show that for the 12 days of autonomous constellation navigation, the user range error of the satellite orbit was 2.5 m, the accuracy of clock error was 3 ns, and the timekeeping accuracy was approximately 1373 ns. The pseudorange observation data of 7 domestic stations and 10 global stations of the International GNSS Monitoring and Assessment System (iGMAS) was used to evaluate the positioning accuracy. The results show a single-frequency horizontal positioning accuracy of 7.4 m, an altitude positioning accuracy of 9.6 m, a dual-frequency horizontal positioning accuracy of 7.1 m, and an elevation positioning accuracy of 8.9 m. Based on the results of the experiment, this paper analyses the time-space reference drift problem that affects the accuracy of autonomous navigation space signals and proposes an optimized solution.