XU Long-xia1, 2, 3, ZHANG Hui-jun1, 2, 3, LI Xiao-hui1, 2

(1. National Time Service Center, Chinese Academy of Sciences, Xi′an 710600, China;

2. Key Laboratory of Precision Navigation and Timing Technology, National Time Service Center,

Chinese Academy of Sciences, Xi′an 710600, China;

3. Graduate University of Chinese Academy of Sciences, Beijing 100039, China)

Abstract: The RAIM(receiver autonomous integrity monitoring) algorithm for multi-mode navigation system is analyzed in this paper. Based on the least squares solution of multi-mode navigation positioning model, the parity vector is developed for the fault detection and fault exclusion. For GPS navigation system and multi-mode GPS/GLONASS/Galileo navigation system, the number of satellites in view of user and the values of DOP(dilution of precision) are simulated on the assumption that there is only one fault in the observed quantities. The values of HPL(horizontal protection level) which are used to measure the availability of RAIM algorithm and the behaviors of fault detection and fault exclusion are compared between these two systems. Simulation results demonstrate that compared with GPS, there are more satellites in view, better availability of RAIM algorithm, and better performance of fault detection and fault exclusion for the multi-mode GPS/GLONASS/Galileo navigation system. Therefore, the multi-mode navigation system not only can provide higher positioning precision, but also can provide better integrity than GPS system.

Key words: RAIM(receiver autonomous integrity monitoring); multi-mode navigation system; fault detection; fault exclusion