Patent ID: 8058868

Claim:
A sensing system for determining an absolute position of a turning device, the sensing system comprising: a first multi-polar magnetic ring concentrically positioned with respect to the turning device, having a plurality of pole pairs, and configured to rotate with the turning device; a second multi-polar magnetic ring having at least one pole pair and configured to rotate with the first multi-polar magnetic ring and the turning device; a first processing unit positioned near the first multi-polar magnetic ring, and configured to determine an angular position of the turning device over one of the pole pairs of the first multi-polar magnetic ring; a first sensor positioned external to the first processing unit and adjacent the second multi-polar magnetic ring, and configured to indicate a first state of the at least one pole pair of the second multi-polar magnetic ring; a second sensor positioned external to the first processing unit, adjacent the second multi-polar magnetic ring, and being spaced apart from the first sensor, and configured to indicate a second state of the at least one pole pair of the second multi-polar magnetic ring; and a second processing unit configured to receive the first and second states and the angular position, and to generate the absolute position of the turning device based on the angular position and the first and second states.