YRP Ubiquitous Networking Laboratory unveiled a system to make communication between a pedestrian and an electric vehicle (EV) via ultra-wide band (UWB) communication at Tronshow2010, a trade show that took place from Dec 9 to 11, 2009, in Tokyo.
With the system, a pedestrian can know the accurate distance to an approaching EV. UWB communication uses electric signals with a bandwidth ranging from about 1GHz, enabling low-power-consumption communication.
The laboratory applied a high-precision distance measurement technology related to UWB communication to a system that helps pedestrians notice approaching cars. There is a system that alerts pedestrians by using their mobile phones, but the UWB-based system can measure the distance more accurately, according to the laboratory.
The prototyped system consists of two terminal devices: one for an EV and another for a pedestrian. And they directly communicate with each other via UWB communication. The device for pedestrians gives warning by screen display, sound, vibration and so forth.
The communication distance between the two devices is about 30m on a straight road. Therefore, the new system is not suited for detecting a vehicle running at a high speed (faster than 40km/h or 24.85mph) or a vehicle appearing from a curved road. However, it can very accurately detect an approaching vehicle in its detection area with a margin of error of 30cm.
The laboratory plans to use a bandwidth ranging from 3 to 5GHz for the prototype.