US Patent 7928829 Method for controlling access to a vehicle

In a method for controlling access to a vehicle (FZ), first an authentication signal is sent from the vehicle to an authorized mobile ID transmitter (IDG), with which authentication signal the ID transmitter is authorized to unlock the vehicle. Subsequently, the distance from the valid authorized mobile ID transmitter to the vehicle is determined. Finally, an unlock signal (ES) is transmitted from the valid authorized mobile ID transmitter to the vehicle, if the distance from the ID transmitter to the vehicle is less than a predetermined first proximity distance (ANRE). In this way an efficient control of access to a vehicle is achieved, wherein the mobile ID transmitter automatically unlocks the vehicle when a certain proximity to the vehicle is identified.