C/N_0 Assessment Based on GPS L5/L1C/A Signal Acquisition in Open-Sky/Light-Urban/Dense-Urban/Indoor Environments with Extended Coherent Integration Time

Chin Lok Tsang ； Yiran Luo ； Bing Xu ； Li-Ta Hsu

《Journal of Aeronautics, Astronautics and Aviation》 55卷2期 Vol.55 No.2 (2023/06) Pp. 169-183

https://doi.org/10.6125/JoAAA.202306_55(2).06

摘要

When the antenna receives the GNSS signals on the ground, the quality of the GNSS measurements will be closely related to the surrounding environment. Few works currently focus on comparing the performance of the legacy and the modern signals in the baseband signal processing level regarding different complicated environments. The paper proposed a long coherent integration algorithm for the GPS L1C/A and L5 signal performance comparison. Making use of the secondary code in the pilot channel of the L5 signal, an across-bit long coherent integration algorithm can be performed that minimizes the squaring loss and improves the signal-to-noise ratio (SNR). Then, with the aid of the bit edge estimated through the L5Q, a long coherent correlation can be directly performed in the L1C/A and L5I channels regardless of the unwanted bit change impact caused by the data symbol transition. The correlation powers are optimized for the legacy and the modern signal comparison in the acquisition process. The carrier-to-noise density ratio (C/N_0) and signal-acquired probability are used as the comparison index in the paper. A large scale of live sky IF data corresponding to different environments is collected for the experiment.

關鍵字

Modernized GNSS ； Code-Parallel acquisition ； Long coherent integration ； C/N_0 assessment ； Urban canyon

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