Patent ID: 7376884

Claim:
A method of determining a first coordinate value of a position with respect to a plurality of first patterns disposed or formed on or in a first substrate using a sensing device, each of the plurality of first patterns representing respective ones of a plurality of first sequences, each of the first sequences consisting of a repeating first codeword of a first cyclic position code, the first cyclic position code having length n 1 and minimum distance, d min 1 the method including: sensing, using the sensing device and from the first substrate, at least part of h 1 of the corresponding first patterns, where h 1 ≧2; obtaining, from each sensed at least part of the first patterns, a respective first subsequence of length w 1 symbols, where w 1 ≧n 1 −d min 1 +1; mapping each of the first subsequences to a respective mapped codeword of the first cyclic position code; determining a first offset indicative of the position, in the corresponding first sequence, between each mapped codeword and the first codeword; deriving, for each of h 1 −1 pairs of the first sequences, a difference between the corresponding pair of first offsets, and thereby deriving a respective one of a plurality of first differences; and deriving, from the plurality of first differences, the first coordinate value.