Patent attributes
A vehicle-mounted device includes a control unit that generates a request signal, a transmission unit that sequentially transmits a request signal generated by the control unit from a plurality of respective transmission antennas, a reception unit that receives a response signal to the request signal, and a storage unit that stores a history of information included in a response signal received by the reception unit, and, in a case where the response signal is newly received by the reception unit, the control unit determines whether or not a vehicle is caused to perform a predetermined operation on the basis of the information included in the response signal and the history of the information included in the response signal stored in the storage unit.
