Abstract: A position finder for vehicles includes, connected to an antenna, a satellite receiver for receiving and evaluating transmitted signals sent by a plurality of satellites, additional sensors for detecting the movement of the vehicle, and a coupler computer, for joint evaluation of the transmitted signals sent by the satellites and of the sensor signals so that instantaneous positional data can be generated. To design less expensive position finders for vehicles, the position finder is characterized in that the additional sensors are sensors that are independent of the vehicle system and the satellite receiver, along with its antenna, the additional sensors and the coupler computer, are arranged in a separate housing having a terminal for a power supply voltage and an interface via which the positional data can be sent.

Abstract: A location sensor in which a satellite receiver, a rotation rate sensor constituting a direction sensor, and an acceleration sensor constituting a displacement sensor are arranged in a housing. The signals of these sensors are conveyed to a common filter, so that the location, the movement velocity, and/or the movement direction can be picked off at the output of the location sensor. The compact arrangement of the individual sensors makes possible multiple utilization of individual components, for example of filters.

Abstract: A method for initialization of a receiver, and a receiver of position signals, are proposed, a sequence of transmitter identifiers being searched through for an active transmitter, and the sequence of transmitter identifiers comprising satellites which are positioned in orbits that are located approximately perpendicular to one another.

Abstract: A device of a vehicle for data transmission to a stationary beacon 91), which has a transceiver, comprising an on-board unit (2) with an antenna (6) for receiving a continuous signal (5), broadcast by the beacon (1), and for transmitting the received signal (5) back after modulation with a data signal (i(t)), is characterized in that the signal (7) transmitted back by the on-board unit (2) is a double-sideband signal. In that case, the on-board unit (2) can be designed as extremely simply and in the simplest case comprises a diode (9) connected to the base of the antenna (6).

Abstract: For the digital data communication between a vehicle (transponder) and a beacon, an automatic gain control wherein the path attenuation between the transponder and the brake increases disproportionately with the distance. A two-stage automatic gain control is included for the gain control. After the first amplifier stage, the output signal is measured and supplied, together with a setpoint value contained in a setpoint memory, to a control amplifier. The output signal of the control amplifier is used both for automatically controlling the first amplifier stage, as well as the second amplifier stage. The automatic control makes it possible to cover only one single lane when automatically debiting highway tolls for a motor vehicle, for example. Influences caused by other motor vehicles on a nearby lane are eliminated.

Abstract: A method and a circuit arrangement for combining several data channels with a transmission channel in which the carrier signal has at least two digital data signals, each with a different frequency, superimposed on it in terms of time. The superimposed signal is transmitted and received by a receiving device. The receiving device decodes the digital data signals and can pass them on, separately, to corresponding devices for further processing. The method and circuit arrangement may be advantageously used for data transmission between a motor vehicle and a fixed beacon. The data to be transmitted may contain traffic guidance data, or data for billing road use fees, for example.

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.