1. A substrate having a position-coding pattern disposed on a surface thereof, said position-coding pattern comprising: a plurality of target elements defining a target grid, said target grid comprising a plurality of cells, wherein each cell has a target element positioned at each corner thereof and neighboring cells share target elements; a plurality of data elements contained in each cell; and a plurality of tags, each tag being defined by a plurality of contiguous cells, each tag comprising respective location data encoded by a respective set of said data elements.