To provide a vehicle inclination angle detector A accurately detecting the rolling/overturn of a vehicle 2 on the basis of behavior in the rolling direction of the vehicle 2, certainly operating an occupant protection means in proper timing, and protecting an occupant from a shock or the like in the rolling/ overturn of the vehicle 2 with high reliability.
A static inclination angle in the rolling direction of the vehicle 2 is detected by first and second acceleration sensors 4, 5, and a dynamic inclination angle θ in the rolling direction of the vehicle 2 is detected by integrating output of an angular velocity sensor 7 with respect to a time. An additional value of the static inclination angle and the dynamic inclination angle θof the vehicle 2 becomes an accurate inclination angle Σ of the vehicle 2, and agrees with an inclination angle at which the vehicle 2 actually inclines. Thereby, the actual inclination angle of the vehicle 2 is accurately detected before the rolling/overturn when the vehicle 2 rolls/overturns, and the occupant protection means such as a curtain shield air bag can be operated in the proper timing.
KOUJIYA MUTSUMASA
OGATA YOSHIHISA
