A method of determining a position of a substrate relative to an imprint template is described, wherein the imprint template has at least three gratings and the substrate has at least three gratings positioned such that each imprint template grating forms a composite grating with an associated substrate grating, the at least three imprint template gratings and associated substrate gratings having offsets relative to one another. The method includes detecting an intensity of radiation which is reflected by the three composite gratings, and using the detected intensities to determine displacement of the substrate or imprint template from a position.