A vehicle authentication system for authenticating a portable ID transmitter with respect to an authentication arrangement of a vehicle in order to release vehicle functions for an operator, includes a portable ID transmitter that has at least one ID transmitter-UWB-antenna. The authentication device has at least one first vehicle-UWB-interface having one first UWB antenna and a second vehicle-UWB interface with a second UWB-antenna. Control for the authentication device are also provided so that an authentication method can be carried out. Optionally, the authentication system can also include LF interfaces with LF antennas and proximity sensors.