Standard Elektrik Lorenz Ag

Alcatel

Daimler Ag

Wolfgang Beier

Horst Idler

Helmut Graf

Michael Wolf

A communications system for registering tolls, with vehicles which have communications devices for wirefree communication between the vehicles and the toll operator which is assigned to them and has a corresponding communications device. In this context, the vehicles transmit toll information relevant to the toll operator in a toll-registration area which is assigned to the toll operator, and the toll operator determines or bills the tolls to be charged therefrom. If the vehicles communicate, by means of their communication devices, with other toll operators outside the toll registration area of the toll operator assigned to them, in order to register tolls, the exchange of toll-related information takes place only when a certificate of the assigned toll operator is successfully transmitted and on the basis of a public key or a private key.

Communications system for registering tolls

Process for transmitting information between moving bodies and a communication device for carrying out this process

Receivers for bandspread signals have a carrier PLL (20) for the carrier frequency and phase and a code PLL (20, 30 . . . 34) for the code frequency and phase. To be able to receive even very noisy signals, the carrier PLL, in particular, must have a very narrow bandwidth. This results in a very narrow capture range. According to the invention, instead of employing a complicated search strategy, advantage is taken of the fact that the code PLL locks in more easily. A signal is taken from the code PLL which indicates the difference between the desired value and the actual value of the code frequency. This signal is fed as an additional control signal to the carrier PLL.

Receiver for bandspread signals, particularly GPS receiver

An improved receiver for modulated bandspread carrier signals is disclosed. The invention includes an antenna for intercepting a plurality of modulated carrier signals bandspread at a first clock rate; a radio frequency section in communication with the antenna for selecting a received signal from the plurality of signals; and an intermediate frequency section in communication with the radio frequency section for converting the received signal to an intermediate frequency signal. The intermediate frequency signal is digitized and multiplied by a pseudo-random code stored in a first memory for demodulation. Successive demodulation products are added, stored and used to provide in-phase (I) and quadrature (Q) signals. Means are provided to for utilizing the I and Q signals to control the rate and the timing of the multiplication of the digitized signal with the pseudo-random code stored in the first memory.

Receiver for bandspread signals

A direction determining system having a Global Positioning System (GPS) receiver, a linear antenna array and a fast switching facility, the linear antenna array comprised of at least two antenna elements and the GPS receiver including two Costas Loops. The fast switching facility permits an input signal received by the two antenna elements to be processed and alternately supplied to the Costas Loops in synchronism for measuring the phases of the input signals received nearly simultaneously. The phase difference between the output signals of the two Costas Loops is measured in a phase meter and the pointing angle of the linear antenna array relative to the direction of a GPS satellite is determined by interferometry.

Direction-determining system

A receiver for bandspread signals having a pseudo-random code stored in the receiver for synchronization with a pseudo-random code (PRC) of a received and modulated signal for recovering the modulation utilizing control loops. The modulated carrier signal is frequency converted, digitized and then multiplied by the stored PRC. The signal provided is sampled at twice the rate at which the PRC is read out of memory and provided to a counter forming I and Q signals from the counter output values in the control loops for determining a plurality of controlled variables required for synchronization and demodulation.

Growing community of inventors

Weil der Stadt, Germany

Wolfgang Beier