Chapter 33 The Development, Test and Application of New Technology on Beidou/GPS Dual-Mode Pseudolites

摘要

Satellite navigation signal was easy to be influenced by urban canyon, highway tunnel, indoor and underground garage. In view of this shading problem, the Beidou/GPS dual-mode pseudolites was developed in China. Firstly, the composition and technical characteristic of pseudolites was introduced. Secondly, Pseudolites compatible with Beidou/GPS signal, navigation message and anti near-far effect was described, then put forward a new high precision time synchronization algorithm between pseudolites and Beidou/GPS. Thirdly, the range stability, navigation chip compatible reception ability, signal coverage and the positioning accuracy was tested in the infield and outfield environment. Test results showed that: by the new time synchronization algorithm, the properties of rubidium clock or crystal oscillator to drive the pseudolites was basically the same, so this pseudolites could use a cheap crystal as the time frequency unit. Under the combined solution between pseudolites and Beidou/GPS, pseudolites could improve the geometric distribution and the positioning accuracy of the navigation system from 10 m up to 5 m. Finally, Verifying the enhanced capabilities of pseudolites in the Mountain valley environment through the practical application data of Jiuzhaigou National Park, the related research results will improve the high availability of China's Beidou satellite navigation system.