Patent ID: 7598847

Claim:
The vehicle theft detection system that is provided in a vehicle, the vehicle theft detection system comprising: at least two types of sensors, which sense a behavior of the vehicle in a parked state and outputs a corresponding sensor signal that indicates the sensed behavior of the vehicle in the parked state; a sensor signal obtaining means for obtaining the sensor signal from each of the at least two types of sensors; an initial value setting means for setting an initial sensor signal of each of the at least two types of sensors, which is initially obtained by the sensor signal obtaining means upon parking of the vehicle, as an initial value of the sensor; a comparing means for comparing each initial value, which is set by the initial value setting means, with a current sensor signal of a corresponding one of the at least two types of sensors, which is currently obtained by the sensor signal obtaining means; a determining means for determining whether the vehicle is stolen based on a comparison result, which is made by the comparing means; a lock state sensing means for sensing a locked state and an unlocked state of a door of the vehicle; and a vertical movement sensing acceleration sensor that senses an acceleration in a vertical direction of the vehicle, wherein the determining means receives a measurement output from the vertical movement sensing acceleration sensor, wherein when the determining means senses the vertical movement of the vehicle based on the measurement output of the vertical movement sensing acceleration sensor, the determining means does not determine that the vehicle is in a stolen state until the unlocked state of the door is sensed by the lock state sensing means, and wherein the determining means determines that the vehicle is in the stolen state when the vertical movement sensing acceleration sensor does not sense the acceleration in the vertical direction of the vehicle for a predetermined time period even in a case where the lock state sensing means does not sense the unlocked state of the door.