Method and devices for identifying a vehicle using a location

A radio beacon for identifying a vehicle using a predetermined location, the vehicle carrying an onboard unit that via radio repeatedly broadcasts status messages that each indicate a current relative distance of the onboard unit from the predetermined location and a radio identifier that changes after each or several status messages, the radio beacon configured to, with the aid of a processor and a transceiver connected thereto,

• receive at least one status message;
• detect a location usage by evaluating the at least one status message based on the relative distance indicated therein;
• transmit an identification request to that onboard unit which is addressed by way of the radio identifier from the at least one status message;
• and
• receive an identification of the onboard unit that remains the same over several radio identifier changes.

An onboard unit, comprising a processor, a satellite navigation receiver for position determination, and a transceiver for radio communication, wherein the onboard unit is configured to, with the aid of the transceiver, repeatedly broadcast via radio status messages, which each contain a radio identifier of the onboard unit that changes after several status changes, wherein the onboard unit is further configured to

• indicate in each status message a current relative distance from a predetermined location, as determined by way of the satellite navigation receiver, the onboard unit further configured to
• receive, from a radio beacon, an identification request that is addressed to the current radio identifier of the unit and contains a cryptographic sender certificate;
• validate the sender certificate;
• and
• if the sender certificate is valid, transmit an identification of the onboard unit to the radio beacon, the identification remaining the same over several changes of radio identifier.