Method to provide access authorization to a motor vehicle

摘要

Transmission units (21,22,23) in a vehicle (1) transmit vehicle signals (FS) to an electronic key (2), bouncing back key signals (SS) as echo signals to the respective transmission unit (TU). The time difference between a vehicle signal and key signals is detected and evaluated. Through successive bidirectional signal transmission between two or more TUs and the electronic key and through the evaluation of time differences, the position of the electronic key is detected in relation to the vehicle and a decision about giving authorized access to the vehicle is made on the basis of determining this position.