| 摘要 |
PROBLEM TO BE SOLVED: To provide a portable key that has a battery and uses power from the battery to transmit an unlocking or locking signal in which reduction in the remaining battery level of the portable key is detected without increasing its size in a keyless entry system for a vehicle in which vehicle-side control means is provided to control the open/closed state of vehicle doors by receiving the unlocking or locking signal from the portable key and reduction in the remaining battery level is easy to notice for users.SOLUTION: Vehicle-side control means (6) has a position detection control section (6A) that communicates with a portable key (4) and detects the position of the portable key (4) at set time intervals and a remaining battery level estimation section (6B) that estimates the remaining level of a battery (14) of the portable key (4) according to a signal received from the portable key (4). |
