Evaluation of GPS/BeiDou Integration Positioning Performance

As a new global navigation system, BeiDou has formally been in operation in the Asian region since December 27, 2012. To evaluate its positioning performance, several days' observation data were collected using a global positioning system (GPS)/BeiDou receiver in Shanghai. In this paper, the constellation and signals of BeiDou are first reviewed. Carrier-to-noise density ratio (C/N-0) and multipath combinations are analyzed, then multipath errors of GPS satellites and BeiDou satellites were compared in terms of elevation angle. A positioning performance comparison of three scenarios was conducted using three indicators including number of visible satellites (NVS), position dilution of precision (PDOP), and accuracy of positioning. All positioning results were solved using a single-point positioning mode. After six months of adjustment, comparison of the positioning performance before BeiDou began providing regional services, there were some significant improvements in performance. The accuracy requirements published before formal operation, in which positioning accuracy is less than 10 m, was met. The results show that the integration system has a large NVS, low PDOP value, and a high level of accuracy and precision. The positioning performance can be improved after using BeiDou, especially under the conditions of urban environment.