Fast Convergence Algorithm of Precise Point Positioning Towards Smartphones and its Application in the Urban Environment

Jiale Wang, Fu Zheng, Chuang Shi, Yong Hu, Yu Xue, Qingcheng Li, Wenyue Chao

Peer Reviewed

Abstract: The prevalence of low-cost GNSS chips that allow multi-constellation, multi-frequency pseudorange, and carrier phase measurements has provided the hardware foundation for implementing precise point positioning (PPP) on smartphones. However, compared to professional geodetic receivers, smartphones suffer from severe multipath effects and signal quality loss, resulting in the convergence time for real-time PPP solutions becoming longer, from several minutes to a few hours, to converge to 1 m accuracy. By establishing high-precision atmospheric products (including ionospheric and tropospheric corrections), we aim to bring smartphone PPP to achieve instantaneous sub-meter positioning performance. For ionospheric Slant TEC (STEC) modeling, we employ the Satellite-based Ionospheric Model (SIM), and the average RMS of the model's accuracy is better than 2 TECU. The Real-Time Tropospheric Grid Point (RTGP) model is based on the GPT2w model, and its accuracy is better than 1.2 cm on average. Both models are updated every 10 s to fulfill the requirements of real-time smartphone applications. Static experimental results in an open urban environment indicate that the Xiaomi Mi8 and Huawei P40 can converge to sub-meter levels within 6 s when utilizing a multi-constellation and dual-frequency PPP solution with precise atmospheric corrections. The positioning accuracy was obtained by Mi8 and P40 with a horizontal RMS of 0.36 m and 0.3 m. In the dynamic experiment with apparent occlusion, the horizontal convergence speed of the atmospheric augmentation PPP solution also showed satisfactory results, with both smartphones converging to 1 m within 5 s. Moreover, the RMS statistics of horizontal positioning accuracy of Mi8 and P40 reach 0.68 m and 0.54 m, respectively. The atmospheric augmentation PPP method presented in this paper effectively improves convergence time and positioning accuracy in the horizontal direction compared to the conventional PPP model and satisfies smartphone users' need for instantaneous sub-meter positioning in urban navigation.
Published in: Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022)
September 19 - 23, 2022
Hyatt Regency Denver
Denver, Colorado
Pages: 3031 - 3044
Cite this article: Wang, Jiale, Zheng, Fu, Shi, Chuang, Hu, Yong, Xue, Yu, Li, Qingcheng, Chao, Wenyue, "Fast Convergence Algorithm of Precise Point Positioning Towards Smartphones and its Application in the Urban Environment," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 3031-3044. https://doi.org/10.33012/2022.18346
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