Keyless and radio based access control system operating method for motor vehicle, involves evaluating received response signal in base station with respect to code information and distance between object and code sensor

摘要

The method involves sending a request signal (2) from a base station (20) assigned to an object. The request signal is received by a code sensor, and is up-modulated on an auxiliary carrier signal with a frequency different from the request signal, where the carrier signal contains code information. An intermediate signal is resent from the code sensor to the base station, and is received as response signal (3) by the base station. The received response signal is evaluated in the base station with respect to the code information and a distance between the object and the code sensor. An independent claim is also included for an access control system for a vehicle, comprising a base station and a code sensor.