專利摘要：
An angle sensing system for sensing a rotating angle of a steering wheel includes a sensing unit, a processing unit, and a storage unit. The sensing unit detects the rotating angle of a steering column connected to the steering wheel and outputting a sensing signal based on the rotating angle. When the steering column rotates for a circle, the sensing signal presents a non-continuous status. The processing unit calculates the relative angle in a single loop of the steering column based on the sensing signal and the number of loops according to the number of the non-continuous status. The storage unit stores the information of the relative angle and the number of loops. Based on the number of loops and the relative angle, the rotating angle of the steering wheel is detected.