A method and system for transferring information between a moving vehicle and a stationary information location having a vehicle detector system with a loop antenna by using the loop antenna as either the receiving antenna for signals transmitted from a moving vehicle or as the transmitting antenna for signals generated by a transmitter located at the vehicle detector site for transfer to a receiver mounted on a moving vehicle. The information is encoded on a carrier having a frequency outside the normal frequency range of the vehicle detector system, preferably by interrupted carrier pattern processing.
This is a continuation of application Ser. No. 462,890 filed Dec. 28, 1989, now U.S. Pat. No. 5,089,815; which is a continuation of Ser. No. 047,833, now abandoned, filed May 8, 1987.
A wire-loop vehicle detector is configured with a vertically oriented blade aligned at an angle to the direction of traffic-flow with each end of the blade extending laterally beyond the normal limits of vehicle presence over the blade. The extended blade configuration of the wire-loop constrains over-passing vehicles to present repeatable inductive signatures while electromagnetic noise and thermal-drift are selectively canceled using a secondary coil to increase the signal-to-noise ratio of inductance measurements. Inductive signatures of vehicles are recorded using a high-speed and high-precision method of making multiple successive measurements of the inductance of a wire-loop as vehicles pass over. Inductive signatures of automotive vehicles are useful for parking-lot revenue control, car-bomb detection, passive security of isolated communities, and other traffic-flow monitoring and control applications.
A communication system is formed by a location information providing unit configured to provide a location information indicating a location of each road related facility arranged along a road, and a communication unit installed on each road related facility, configured to transmit the location information of each road related facility to a terminal device of a user on the road by using weak radio signals, such that the terminal device that can receive the weak radio signals can detect a location of the terminal device according to the location information.
In an apparatus for the transfer of information in motor vehicle traffic between a fixed-position transmitter-building element near a roadway and a receiver arranged in a vehicle, the transmitter-building element emits a coded information signal and the receiver of the vehicle driving past the transmitter-building element displays information from the information signal in the vehicle. In order to make shielding measures unnecessary, with an uncomplicated supply of energy to the transmitter-building element and small construction costs therefor, the transmitter-building element (1) is built into roadway pavement (12). The energy necessary for transmitting the information signal is received by the transmitter-building element (1) from the vehicle (13) which is driving above it. The receiver (4, 15, 16) has an antenna arrangement (14) which is arranged in a floor area of the vehicle (13) to transfer the necessary transmitting energy to the transmitter-building element (1) and receive the emitted information signal from the transmitter-building element (1).
A method and apparatus is provided for determining if a vehicle with an operating engine is at a particular location, the apparatus comprising: an antenna comprising a continuous wire formed into at least one loop; and a means to determine when the antenna is exposed to an oscillating electromagnetic field having a frequency between about 700 and about 2100 Hz of a strength characteristic of a vehicle's alternator operating in the vicinity of the antenna. In a preferred embodiment of the present invention, the sensor of the present invention further comprises a means to generate a signal when the antenna is exposed to the oscillating electromagnetic field having a frequency between about 700 and about 2100 Hz of a strength characteristic of a vehicle's alternator operating in the vicinity of the antenna, and the signal is used as an input into a logic system that requires that the signal not be generated in order for a refuelling system to refuel a vehicle in the vicinity of the antenna. The antenna is preferably a figure eight loop antenna placed in pavement below the location at which the vehicle is expected to be. The sensor of the present invention is particularly applicable as a input to disenable a fuel pump at a refuelling station.
Methods for a determining a normalized lane occupancy and for monitoring signal quality for a vehicle detection system. Such methods include, in one embodiment, measuring a speed of a vehicle with an inductive vehicle detector, measuring an on-time for the vehicle crossing a wire loop sensor of the inductive vehicle detector, determining an inductive length of the vehicle from the measured speed, and computing a normalized on-time by subtracting a longitudinal length of the wire loop sensor from the inductive length and dividing the difference by the measured speed.
