Sensing device for determining an angular position of a steering wheel on a steering column in a vehicle

A sensing device for determination of an angular position of a steering wheel on a steering column in a vehicle, said sensing device comprising

• means for generating a fine code signal, said fine code signal repeating after a revolution of the steering column, said means for generating a fine code signal including a first coded disk provided with a first code structure, a first plurality of receiving devices and means for reading off said first code structure from the first coded disk to form said fine code signal, wherein said first plurality of receiving devices consists of nine of said receiving devices spaced 40.degree. from each other around an outer periphery of the first coded disk and the first code structure on the first coded disk defines a Gray code;
• means for generating a gross code signal including a second coded disk provided with a second code structure and a second plurality of receiving devices including means for reading off said second code structure from the second coded disk to form said gross code signal;
• means for rotating the second coded disk geared down at a predetermined gear ratio relative to the first coded disk;
• and means for combining the fine code signal and the gross code signal to generate an angular position signal characteristic of an angular position of the steering wheel;
• wherein at least one of said first and second coded disks is a magnetically coded disk provided with a predetermined sequence of alternating North and South pole magnetic regions to provide said code structure and said receiving devices associated with the magnetically coded disk comprise Hall switching devices located on one side of said magnetically coded disk and wherein the first plurality of receiving devices and the second plurality of receiving devices are arranged in a single plane.