Patent ID: 7616100

Claim:
An antitheft system for use in a vehicle that is equipped with a gyro sensor and a temperature sensor for sensing temperature of the gyro sensor so as to provide temperature compensation for a signal from the gyro sensor, the antitheft system comprising: an angle sensor for outputting a signal that represents a body angle of the vehicle; an angle variation determination unit for determining an angle variation of the body angle at a predetermined interval based on the signal outputted from the angle sensor; a theft detection unit for determining whether the vehicle is in a theft condition based on a comparison of the angle variation with a predetermined value; and a temperature variation calculator for calculating an amount of temperature variation of the temperature detected by the temperature sensor, wherein the angle variation determination unit is configured to receive, as the temperature of the angle sensor, the temperature of the gyro sensor, and compensates the signal from the angle sensor based on the temperature of the angle sensor sensed by the temperature sensor before determining the angle variation, wherein the theft detection unit discontinues determination of the theft condition when the amount of the temperature variation is equal to or greater than a predetermined value.