Patent ID: 7082562

Claim:
A method of determining a position with respect to a first pattern disposed or formed on or in a substrate using a sensing device, the first pattern representing a first sequence of at least 2n symbols, the first sequence consisting of a repeating first codeword of a first cyclic position code, the first cyclic position code having length n and minimum distance d min , the method including: sensing, using the sensing device and from the substrate, at least part of the first pattern; obtaining, from the sensed at least part of the first pattern, a first subsequence of length w symbols, where w≧n−d min +1; mapping the first subsequence to a mapped codeword of the first cyclic position code; and determining a first offset, modulo n, in the first sequence, between the mapped codeword and the first codeword, the offset being indicative of the position.