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Abstract

A method of determining a coordinate value of a position with respect to patterns of a substrate using a sensing device is provided. Each pattern represents respective sequences. Each sequence consists of a repeating codeword of a cyclic position code. The cyclic position code has length n.sub.1 and minimum distance d.sub.min.sub.1. The method includes sensing, using the sensing device, at least pan of h.sub.1 of the corresponding patterns, where h.sub.1.gtoreq.2, obtaining, from each of h.sub.1 sensed patterns, a respective subsequence of length w.sub.1 symbols, where w.sub.1.gtoreq.n.sub.1-d.sub.min.sub.1+1, mapping each of the subsequences to a respective mapped codeword of the cyclic position code, determining an offset indicative of the position, in the corresponding, sequence, between each mapped codeword and the codeword, deriving, for each of h.sub.1-1 pairs of the first sequences, a difference between the corresponding pair of offsets, and thereby deriving a respective difference and as such the coordinate value.

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