Leopold Kostal Gmbh & Co. Kg

Michael Fromm

Volker Pretzlaff

Rainer Vens

Dirk Wolf

Paul Vogels

Detlev Kramer

Peter Raab

A method and device for checking keyless vehicle access authorization of an operator. The method includes transmitting a code signal from a base station to a mobile identification (ID) transmitter carried by the operator. In response to receiving the code signal, the ID transmitter performs an action which is indicative of a reply signal that is detectable by the base station. The difference of a signal characteristic between a reference code signal monitored at the base station and the reply signal received by the base station is then determined. The signal characteristic correlates with signal propagation time and changes as a function of the distance between the base station and the ID transmitter. The distance between the base station and the ID transmitter is then determined on the basis of a relative determination based on the difference of the signal characteristic between the reference code signal and the reply signal.

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Dortmund, Germany

Michael Fromm