Patent 7515034 was granted and assigned to Panasonic on April, 2009 by the United States Patent and Trademark Office.
A vehicle remote-operation apparatus is provided which transmits a regular authentication request signal from a vehicle-outside antenna and simultaneously transmits an interference wave for negating this authentication request signal from a vehicle-inside antenna, so that the communicable range can be limited between a radio portable unit allocated an identification code unique to a vehicle and the vehicle-outside antenna. Thereby, authentication communication is established only for a regular communication request.