Patent ID: 7471187

Claim:
An unlocking system comprising: a portable device having a transmitting means for transmitting ID information; and an unlocking controller for receiving the ID information transmitted from the transmitting means and performing unlocking control of a door based on the ID information received from the transmitting means, wherein the portable device includes: a receiving means for receiving one of a first request signal and a second request signal transmitted from the unlocking controller; and a transmission control means for making the transmitting means transmit the ID information after reception of the one of the request signals by the receiving means, wherein the receiving means varies a reception sensitivity of the one of the request signals, and wherein the unlocking controller includes: an intermittent transmitting means for intermittently transmitting the first request signal to the portable device outside of a vehicle; a human detecting means for detecting presence of a human around the door; and a detection transmitting means for transmitting the second request signal to the portable device based on a human detection result of the human detecting means, wherein the detection transmitting means transmits the second request signal to the outside of the vehicle with an output power level higher than the output power level of the intermittent transmitting means, wherein the detection transmitting means transmits the second request signal to the outside of the vehicle by one shot every time the human detecting means detects the presence of the human, and wherein the portable device further includes: a determination means for determining, based on an initial signal of the request signal, whether the one of the request signals for which reception of the one of the request signals by the receiving unit is started is the second request signal from the detection transmitting means when the reception of the one of the request signals is started by the receiving means; and a sensitivity setting means for setting the reception sensitivity of the receiving means to a sensitivity lower than that at a reception time of the initial signal if it is determined, by the determination means, that the initial signal is a request from the detection transmitting means.