Matsushita Electric Industrial Co., Ltd.

Akihiro Inui

Makoto Takemoto

Masaki Terashima

Yoshiteru Hirano

A road antenna apparatus includes a road antenna which is mounted on a post and at an elevated position on a road R and establishes radio communication with an on-vehicle radio device mounted in a vehicle which is traveling over the road; a controller controls a level of a transmission output signal of the antenna based on a receiving rate of the transmission output signal. A laser-beam emitting device is mounted on the road antenna and radiates a laser beam onto the surface of the road. A laser-beam receiving device mounted on the road receives the laser beam emitted from the laser-beam emitting device. The controller stops the operation of the antenna when the laser-beam receiver device cannot receive the laser beam.

Road antenna apparatus including laser-beam emitting device

A road antenna apparatus includes a road antenna which is mounted on a post and at an elevated position on a road R and establishes radio communication with an on-vehicle radio device mounted in a vehicle which is traveling over the road; A controller controls a level of a transmission output signal of the antenna based on a receiving rate of the transmission output signal. A laser-beam emitting device is mounted on the road antenna and radiates a laser beam onto the surface of the road. A laser-beam receiving device mounted on the road receives the laser beam emitted from the laser-beam emitting device. The controller stops the operation of the antenna when the laser-beam receiver device cannot receive the laser beam.

Road antenna controlled on the basis of receiving rate

A road antenna apparatus includes a road antenna which is mounted on a post and at an elevated position on a road R and establishes radio communication with an on-vehicle radio device mounted in a vehicle which is traveling over the road. A receiving rate of the established radio communication is detected. A transmission output is set based on detecting a suitable receiving rate for a desired communications area established between the transmitter and the receiver.

Method and device for setting a communications area of a road antenna apparatus

A road antenna apparatus includes a road antenna which is mounted on a post and at an elevated position on a road R and via a radio wave establishes radio communication with an on-vehicle radio device mounted in a vehicle which is traveling over the road; and a determining device provided in the antenna and determining whether the travel speed of the vehicle is appropriate for a speed limit imposed on a road, on the basis of the travel speed of the vehicle based on a signal corresponding to a reflected wave, the reflected wave being produced as a result of the radio wave emitted from the antenna being reflected by the vehicle.

Growing community of inventors

Kanagawa, Japan

Akihiro Inui