An apparatus for estimating a position of a movable stage, the apparatus comprising: a stator comprising an array of sensors arranged relative to one another to provide a plurality of stator-Y oriented sensor columns and a plurality of stator-X oriented sensor rows; each stator-Y oriented sensor column comprising a plurality of sensors generally aligned with one another in a stator-Y direction and at least one pair of sensors in each stator-Y oriented sensor column spaced apart from one another in the stator-Y direction by a pitch P y; and each stator-X oriented sensor row comprising a plurality of sensors generally aligned with one another in a stator-X direction, the stator-X direction non parallel with the stator-Y direction, and at least one pair of sensors in each stator-X oriented sensor row spaced apart from one another in the stator-X direction by a pitch P x; a movable stage comprising a first Y-magnet array comprising a plurality of first magnetization segments generally linearly elongated in a stage-Y direction, each first magnetization segment having a stage-Y direction length, L yy, and a magnetization direction generally orthogonal to the stage-Y direction, the magnetization directions of the plurality of first magnetization segments exhibiting a first magnetic spatial period λ x over a stage-X direction width, W yx, of the first Y-magnet array; a controller connected to receive information based on an output from each of the sensors and configured to use the information to determine a stator-X direction position of the movable stage; wherein the pitch P x conforms generally with P x = nλ x N, where n and N are integers and n N is not an integer. a stator comprising an array of sensors arranged relative to one another to provide a plurality of stator-Y oriented sensor columns and a plurality of stator-X oriented sensor rows; each stator-Y oriented sensor column comprising a plurality of sensors generally aligned with one another in a stator-Y direction and at least one pair of sensors in each stator-Y oriented sensor column spaced apart from one another in the stator-Y direction by a pitch P y; and each stator-X oriented sensor row comprising a plurality of sensors generally aligned with one another in a stator-X direction, the stator-X direction non parallel with the stator-Y direction, and at least one pair of sensors in each stator-X oriented sensor row spaced apart from one another in the stator-X direction by a pitch P x; a movable stage comprising a first Y-magnet array comprising a plurality of first magnetization segments generally linearly elongated in a stage-Y direction, each first magnetization segment having a stage-Y direction length, L yy, and a magnetization direction generally orthogonal to the stage-Y direction, the magnetization directions of the plurality of first magnetization segments exhibiting a first magnetic spatial period λ x over a stage-X direction width, W yx, of the first Y-magnet array; a controller connected to receive information based on an output from each of the sensors and configured to use the information to determine a stator-X direction position of the movable stage; wherein the pitch P x conforms generally with P x = nλ x N, where n and N are integers and n N is not an integer.