The invention pertains to a measurement system for measuring displacement of a moveable object relative to a base in at least a first direction of measurement, the moveable object having at least one reference part that is moveable in a plane of movement relative to the base, the actual movements of the reference part being within an area of said plane of movement that is bounded by a closed contour having a shape. The measurement system comprises a sensor head that operatively communicates with a planar element. The sensor head is mounted onto the base and the planar element being mounted onto the reference part of the moveable object or the other way around, wherein the planar element has a shape that is essentially identical to the shape of the closed contour.