MEMS-Enhanced Smartphone GNSS High-Precision Positioning for Vehicular Navigation in Urban Conditions

Objectives: Smartphones have become the mainstream terminal carrier of navigation and location services for mass users by virtue of their ubiquity, portability, and low cost. With the opening of their multi-frequency and multi-constellation global navigation satellite system (GNSS) observations, the research on high-precision positioning of smartphones has been further stimulated. However, limited by the performance of consumer-grade GNSS devices, the satellite observations of smartphones present problems such as serious signal attenuation, large pseudorange noise, and many cycle slips; and also affected by the complex urban environment, the continuity and reliability of smartphone GNSS positioning is also difficult to guarantee.Methods: A smartphone GNSS/MEMS (micro-electro mechanical system) integrated high-precision positioning scheme for vehicular navigation in urban conditions is proposed. Firstly, a velocity-constrained GNSS differential filtering positioning model is constructed to realize precise positioning in a general observation environment; then, through the built-in MEMS of smartphone and virtual constraints of vehicle motion, GNSS precise positioning is enhanced in challenging environments.Results: The experiment results show that, in open sky and tree occlusion conditions, the improved method can achieve decimeter-to-meter positioning accuracy, which is 35.2% and 78.9% higher than conventional method, respectively; in viaduct occlusion conditions, the accuracy and continuity of GNSS/MEMS fusion positioning are the best; in tunnel conditions, the cumulative position error of the MEMS mechanization is about 2.5%. Conclusions: The results preliminarily show that smartphone GNSS has lane-level positioning capabilities in open-sky environments, and GNSS/MEMS fusion can improve the accuracy and continuity of smartphone positioning in urban challenging environments. © 2022 Wuhan University. All rights reserved.