Abstract: The data communication device is designed for a towed vehicle having wheels rear lights, brake lights, turn signal lights and an anti-lock braking system, that is drawn by a motor vehicle. This data communication device includes an electrical cable connection (19) for supplying electrical power from the towing vehicle to the rear, brake and turn signal lights; an electrical pulse generator and electrical power supply circuit (14) for producing direct current from wheel motion of the towed vehicle; a rechargeable battery (15) to provide a supplementary direct current in addition to this direct current, when necessary; a controller (10) for the anti-lock braking system including a data producing unit (7) for producing data including mileage covered by the towed vehicle and a wireless transponder (6) operating the gigahertz range for transmission and reception of data from the data producing unit to and from an external data transmitting and receiving station (1).

Abstract: According to the present invention, a method is proposed for determining the position of a vehicle, in which the vehicle performs a data transmission in the short-range field of at least one beacon. By means of data transmission with at least two or three beacons, an assignment of data transmission and vehicle position within a communications zone can be made. Relative velocities of the vehicle are determined from the data transmission signals sent by the vehicle and received by the beacons, in each instance. The lane or the position of the vehicle sending the data is determined from the velocity ratio or from several velocity ratios. A preferred use is intended to be electronic collection of road use fees or checking of road access entitlement.

Abstract: A method for effecting a wireless exchange of data between a stationary station and transmitter/receivers on board objects, particularly vehicles moving relative to the stationary station. The reception profiles of an antenna array having a plurality of receiving antennas is directed electronically onto an object. The transmitter/receivers on the object transmit, in response to the received signal, an answer signal having the same carrier frequency as the signal received and having a level which is proportional to the level of the signal received. In the antenna array, a transmitting antenna is associated with each receiving antenna, and the transmitting antenna sends out signals having a transmission profile which corresponds to the reception profile of the receiving antenna. The damping factors of transmission profile and reception profile are thereby multiplied by each so that two relatively simple circuits are necessary in order to achieve a desired high side-lobe damping.

Abstract: An on-board unit includes at least one receiving and transmitting antenna for a bidirectional transmission of data which works in accordance with the transponder method. To compensate for interference fading, a high-frequency amplifier is connected in an incoming circuit to the demodulator/modulator, through which the transmission range of the transmission distance is improved as well. The same amplifier and the demodulator/modulator can be used in downlink and uplink operation. In uplink operation, the demodulator/modulator can alternatively subject the carrier signal to amplitude shift keying or phase shift keying.

Abstract: A method for implementing a wireless data exchange between a fixed station and sending/receiving devices on board objects moving relative to the fixed station, preferably in lanes, and particularly vehicles. Using an antenna arrangement of the fixed station, the sending and/or receiving profile of which can be electronically aligned with an object, allows reliable determination of location using the antenna arrangement, in that in a first phase, a search territory is swept and checked for response signals from objects by means of a varying alignment of the sending and/or receiving profile. The time of reception of a response signal is correlated with the instantaneous adjustment values of the sending and/or receiving profile to determine the location. In a second phase, the sending and/or receiving profile is fixed on a sending/receiving device of an object whose location has been determined, and it is tracked, if necessary, while the data exchange is conducted.

Abstract: In a communication system for data transmission from a moving vehicle to a stationary beacon (1) which has a transceiver in which a signal is broadcast by the beacon (1) and received by an antenna (5, 5') of an on-board unit (4) of the vehicle and after a modulation with a data signal is transmitted back again to the beacon (1), where the data are extracted from the returned signal, the reliability of transmission for the data is increased by providing that the on-board unit (4) has at least two modulators (6, 6'), with which independently of one another the received signal is modulatable with the data signal and can be transmitted back in different ways. The transmission in different ways of the signals modulated independently of one another can be done by means of spatial separation of the antennas (5, 5') and/or by means of polarizing the broadcast signals differently from one another.

Abstract: A system, for bidirectional transmission of electromagnetic data signals between a stationary unit and a vehicle unit, in which at least two antennas can be used, is proposed. The antennas are aligned at a predetermined distance and at a predetermined height from one another, in such a way that reflection from the roadway and from vehicles is minimized. In the uplink mode, the antenna having the best reception properties is selected, so that reliable data transmission to the stationary unit takes place.

Abstract: A system is proposed for bidirectional electromagnetic transmission of data signals between at least two stationary units and one vehicle unit. The stationary units in the downlink mode synchronously transmit the data signals to the vehicle unit and have different carrier frequencies. In the uplink mode, the data signals are transmitted from the vehicle unit to the stationary units by the semipassive transponder principle. In the process, the data signals of the vehicle unit are frequency-modulated to the various carrier frequencies of the stationary units. This arrangement improves the reliability of bidirectional data transmission. A preferred application is data exchange for traffic control systems between stationary beacon units and moving vehicles.