城市场景智能手机GNSS/MEMS融合车载高精度定位

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

智能手机凭借其普遍性、便携性和低成本等优势,已成为大众用户导航与位置服务的主流终端载体,其多频多系统GNSS(global navigation satellite system)观测值的开放进一步激发了手机高精度定位的研究。然而,受限于消费级GNSS器件性能,手机卫星观测值呈现出信号衰减严重、伪距噪声大、粗差周跳多等问题;并且受城市复杂环境影响,手机GNSS定位的连续性、可靠性也难以保证。提出一种城市场景手机GNSS/MEMS(micro-electro mechanical system)融合的车载高精度定位方案。首先,构建了速度约束的GNSS差分定位模型;然后,通过手机内置MEMS与车辆运动约束,在挑战环境下进行GNSS/MEMS融合精密定位。实验结果表明,在开阔和树荫场景下,速度约束方法可达到分米至米级定位精度,相比于常规方法分别提升了35.2%和78.9%;在高架场景下,GNSS/MEMS融合定位的精度和连续性均提升显著;在隧道场景下,MEMS推算位置累积误差约为2.5%。实验结果初步表明,手机GNSS具备开阔环境下的车道级定位能力,手机GNSS/MEMS融合可提升城市复杂环境下车载定位的精度和连续可用性。

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 highprecision positioning scheme for vehicular navigation in urban conditions is proposed. Firstly, a velocityconstrained 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.