Patent ID: 7699435

Claim:
A system for determining a position of an object moveable along a path, comprising: an encoder strip positioned along the path, the encoder strip having a plurality of uniquely spaced second markings formed on a surface so that the surface includes a plurality of pairs of adjacent second markings wherein a distance between each pair of adjacent uniquely spaced second markings is different from distances between all other pairs of adjacent uniquely spaced second markings; a sensor coupled to the object adjacent to the encoder strip and operable to detect the uniquely spaced second markings as the object moves along the path; a controller in communication with the sensor and operable, as the object moves along the path, to at least indirectly identify a value corresponding to a distance between a pair of detected adjacent uniquely spaced second markings and to determine a position of the object along the path based at least in part on that value; and, reference data at least indirectly correlating each of a series of values associated with distances with position information, each distance value corresponding to a distance between an adjacent pair of second markings on the encoder strip, the position information at least indirectly identifying the positions of the adjacent pair of second markings along the path, where the controller is operable to determine a position of the object along the path by using the identified value associated with a distance to look-up position information in the reference data.