Patent ID: 6437706
Filing Date: 2002-08-20
Classification: G07B,G08G

Abstract:
A toll collection system communication method which charges a car passing through a communication area in a tollgate without a stop, by radio communication between a roadside antenna in the tollgate and a vehicle-mounted antenna in the car, the method comprising the steps of:detecting a car passing through a detection area including a communication area and a given area just before the communication area; calculating, when a car is present in the communication area, a plurality of electromagnetic wave beam paths of direct and reflected waves which connect the roadside antenna and the vehicle-mounted antenna; selecting a radiation direction of the wave beam paths whose communication sensitivity is the highest among the wave beam paths as radiation direction 1; defining the radiation direction of the wave beam paths other than the beam paths in the radiation direction 1 to cars outside the communication area as radiation direction 2; and controlling a directional pattern of the roadside antenna so that the intensity of the beam in the radiation direction 1 is over a first intensity, and that of the beam in the radiation direction 2 is below a second intensity of an intensity which disables communication.