School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Sensors (Basel). 2023 Mar 30;23(7):3624. doi: 10.3390/s23073624.
Precise pedestrian positioning based on smartphone-grade sensors has been a research hotspot for several years. Due to the poor performance of the mass-market Micro-Electro-Mechanical Systems (MEMS) Magnetic, Angular Rate, and Gravity (MARG) sensors, the standalone pedestrian dead reckoning (PDR) module cannot avoid long-time heading drift, which leads to the failure of the entire positioning system. In outdoor scenes, the Global Navigation Satellite System (GNSS) is one of the most popular positioning systems, and smartphone users can use it to acquire absolute coordinates. However, the smartphone's ultra-low-cost GNSS module is limited by some components such as the antenna, and so it is susceptible to serious interference from the multipath effect, which is a main error source of smartphone-based GNSS positioning. In this paper, we propose a multi-phase GNSS/PDR fusion framework to overcome the limitations of standalone modules. The first phase is to build a pseudorange double-difference based on smartphone and reference stations, the second phase proposes a novel multipath mitigation method based on multipath partial parameters estimation (MPPE) and a Double-Difference Code-Minus-Carrier (DDCMC) filter, and the third phase is to propose the joint stride lengths and heading estimations of the two standalone modules, to reduce the long-time drift and noise. The experimental results demonstrate that the proposed multipath error estimation can effectively suppress the double-difference multipath error exceeding 4 m, and compared to other methods, our fusion method achieves a minimum error RMSE of 1.63 m in positioning accuracy, and a minimum error RMSE of 4.71 m in long-time robustness for 20 min of continuous walking.
基于智能手机级传感器的精确行人定位已经成为多年来的研究热点。由于大众市场上的微机电系统（MEMS）磁强计、角速度计和重力计（MARG）传感器性能较差，独立的行人航位推算（PDR）模块无法避免长时间的航向漂移，从而导致整个定位系统的失败。在户外场景中，全球导航卫星系统（GNSS）是最受欢迎的定位系统之一，智能手机用户可以使用它来获取绝对坐标。然而，智能手机超低成本的 GNSS 模块受到天线等组件的限制，因此容易受到严重的多径效应干扰，这是智能手机基于 GNSS 定位的主要误差源之一。在本文中，我们提出了一种多阶段 GNSS/PDR 融合框架，以克服独立模块的局限性。第一阶段是基于智能手机和参考站建立伪距双差，第二阶段提出了一种基于多径部分参数估计（MPPE）和双差码减载波（DDCMC）滤波器的新的多径抑制方法，第三阶段是提出了两个独立模块的联合步长和航向估计，以减少长时间漂移和噪声。实验结果表明，所提出的多径误差估计方法可以有效地抑制双差多径误差超过 4 米，与其他方法相比，我们的融合方法在定位精度方面实现了最小误差 RMSE 为 1.63 米，在 20 分钟连续行走的长时间稳健性方面实现了最小误差 RMSE 为 4.71 米。
