Adaptive Correlation Space Adjusted Open-Loop Tracking Approach for Vehicle Positioning with Global Navigation Satellite System in Urban Areas.
For vehicle positioning with Global Navigation Satellite System (GNSS) in urban areas, open-loop tracking shows better performance because of its high sensitivity and superior robustness against multipath. However, no previous study has focused on the effects of the code search grid size on the code phase measurement accuracy of open-loop tracking. Traditional open-loop tracking methods are performed by the batch correlators with fixed correlation space. The code search grid size, which is the correlation space, is a constant empirical value and the code phase measuring accuracy will be largely degraded due to the improper grid size, especially when the signal carrier-to-noise density ratio (C/N₀) varies. In this study, the Adaptive Correlation Space Adjusted Open-Loop Tracking Approach (ACSA-OLTA) is proposed to improve the code phase measurement dependent pseudo range accuracy. In ACSA-OLTA, the correlation space is adjusted according to the signal C/N₀. The novel Equivalent Weighted Pseudo Range Error (EWPRE) is raised to obtain the optimal code search grid sizes for different C/N₀. The code phase measuring errors of different measurement calculation methods are analyzed for the first time. The measurement calculation strategy of ACSA-OLTA is derived from the analysis to further improve the accuracy but reduce the correlator consumption. Performance simulation and real tests confirm that the pseudo range and positioning accuracy of ASCA-OLTA are better than the traditional open-loop tracking methods in the usual scenarios of urban area.
Key Laboratory of Electronic and Information Technology in Satellite Navigation (Beijing Institute ofTechnology), Ministry of Education, School of Information and Electronics, Beijing Institute of Technology, No. 5 Zhongguancun South Street, Haidian District, Beijing 100081, China. ruanhang@bit.edu.cn.
Hang
H
Ruan
Key Laboratory of Electronic and Information Technology in Satellite Navigation (Beijing Institute ofTechnology), Ministry of Education, School of Information and Electronics, Beijing Institute of Technology, No. 5 Zhongguancun South Street, Haidian District, Beijing 100081, China. lijian_551@bit.edu.cn.
Jian
J
Li
Key Laboratory of Electronic and Information Technology in Satellite Navigation (Beijing Institute ofTechnology), Ministry of Education, School of Information and Electronics, Beijing Institute of Technology, No. 5 Zhongguancun South Street, Haidian District, Beijing 100081, China. aerolong@bit.edu.cn.
Lei
L
Zhang
Key Laboratory of Electronic and Information Technology in Satellite Navigation (Beijing Institute ofTechnology), Ministry of Education, School of Information and Electronics, Beijing Institute of Technology, No. 5 Zhongguancun South Street, Haidian District, Beijing 100081, China. longteng@bit.edu.cn.
Teng
T
Long
GNSS; open-loop tracking; pseudo range accuracy; vehicle positioning