The popularity of intelligent transportation system (ITS) applications urges the development of vehicle positioning system that satisfies the availability, precision and accuracy requirements. Lane level (the exact lane on the road) positioning or even in-lane level (the exact location within the lane) positioning are expected in all driving environments at all times. In addition to the existing vehicle positioning technologies, such as Global Positioning System (GPS), terrestrial radio (e.g., cell phone, AM, FM and digital TV) and feature-based sensors (e.g., vision, LiDAR and RADAR), we propose a complementary vehicle positioning system based on ubiquitous retroreflective transportation infrastructures. Low-cost photodiodes are mounted on the headlights to sense the retroreflected optical signals from on-road safety device, such as raised pavement marker (RPM). A liquid crystal display (LCD) shutter is installed on the RPM to distinguish the retroreflected light signals from different RPMs and from the environmental reflection. By sensing the angle-of-arrival of the retroreflected light beam from the RPMs (i.e., landmarks), the vehicle realizes lane level positioning based on triangulation. Advanced positioning solution is proposed by integrating dead reckoning and Kalman filter to advance the lane level positioning to in-lane level positioning. Extensive experimental results reveal that the proposed vehicle positioning system achieves sub-meter level location accuracy.

智能交通系统（ITS）应用的普及促使车辆定位系统的发展，以满足可用性，精度和准确性的要求。在所有驾驶环境中，始终都希望车道高度（道路上的确切车道）定位甚至车道内高度（车道内的精确位置）定位。除了现有的车辆定位技术，例如全球定位系统（GPS），地面无线电（例如手机，AM，FM和数字电视）和基于特征的传感器（例如视觉，LiDAR和RADAR）之外，我们还建议一种基于无所不在的回射交通基础设施的互补车辆定位系统。低成本光电二极管安装在前灯上，以感应来自道路安全设备的回射光信号，例如凸起的路面标记（RPM）。在RPM上安装了液晶显示器（LCD）快门，以区分来自不同RPM和环境反射的回射光信号。通过感测来自RPM（即地标）的回射光束的到达角，车辆可实现基于三角测量的车道高度定位。通过结合航位推算和卡尔曼滤波器，提出了一种先进的定位解决方案，将车道高度定位提高到车道内高度定位。大量的实验结果表明，所提出的车辆定位系统达到了亚米级的定位精度。通过感测来自RPM（即地标）的回射光束的到达角，车辆可实现基于三角测量的车道高度定位。通过结合航位推算和卡尔曼滤波器，提出了一种先进的定位解决方案，将车道高度定位提高到车道内高度定位。大量的实验结果表明，所提出的车辆定位系统达到了亚米级的定位精度。通过感测来自RPM（即地标）的回射光束的到达角，车辆可实现基于三角测量的车道高度定位。通过结合航位推算和卡尔曼滤波器，提出了一种先进的定位解决方案，将车道高度定位提高到车道内高度定位。大量的实验结果表明，所提出的车辆定位系统达到了亚米级的定位精度。