Patent ID: 6941241

Claim:
A method for measuring an absolute steering angle Φ of a steering shaft for a vehicle using a first rotatable body that rotates together with the steering shaft of the vehicle at a predetermined rotation ratio, the method comprising: obtaining a measurement value Ψ M ′ of a relative rotational angle Ψ′ of the first rotatable body using a first angle sensor having a measurement range of Ω; obtaining a present value for a frequency i-value of the first rotatable body by comparing the present Ψ M ′ value to a previous Ψ M ′ value; and obtaining a present value for an absolute steering angle Φ1 of the steering shaft from a present value for an absolute rotational angle Ψ of the first rotatable body, using the Ψ M ′ value and the present i-value.