| 摘要 |
PROBLEM TO BE SOLVED: To provide keyless entry device capable of clearly determining whether or not relay attack is performed with a simple configuration.SOLUTION: A keyless entry device 100 includes a vehicle side device 10 transmitting a request signal, and a portable machine 20 receiving the request signal and transmitting an answer signal in correspondence with the request signal. A portable machine side receiving section 22 receives a communication signal including the request signal or a fraud signal having a frequency same with that of the request signal, a portable machine control section 25 detects receiving intensity of a fundamental wave of the received communication signal and receiving intensity of a harmonic of the communication signal, and the answer signal including information based on the receiving intensity of the fundamental wave and the receiving intensity of the harmonic is generated, and is transmitted from a portable machine transmitting section 21. A vehicle side control section 15 determines whether the answer signal is a signal through a fraud relay machine or a regular signal not through the relay machine on the basis of the information on the receiving intensity of the fundamental wave and the receiving intensity of the harmonic.SELECTED DRAWING: Figure 2 |
