Approaching vehicle alert system for pedestrians using UWB impulse radio

Accidents between battery-operated vehicles and pedestrians are expected to increase as electric vehicles (EV) or plug-in hybrid vehicles (PHV) are widely used in near future because of small ambient noise of EV/PHV. To prevent such accidents, a portable alert system for pedestrians to detect approaching vehicle is proposed in this paper. The alert system exploits ultra-wideband impulse radio (UWB-IR) for accurately measuring a distance between a portable mobile terminal and a target vehicle, which is measured using a two-way time-of-arrival (TOA) method. The mobile terminal implements a prototype GUI for alerting the user from an approaching vehicle. Field experiments have been conducted using real UWB-IR devices when the target vehicle is stationary and moving at a constant speed, to evaluate accuracy and precision of the proposed alert system. Experimental results show that the proposed system achieves 30 cm accuracy and 1 m precision while the vehicle runs at 30 km/h.