Apparatus for providing a graphic representation or graphic representation sequence for detection by a detector, comprising: a sequence of graphic representations along an optical axis, wherein the graphic representations comprise a code, code sequence, binary code, bar code or data matrix code or a combination or superposition thereof, an optical device for focusing on at least one of the graphic representations, so that the at least one of the graphic representations is visible by a detector, a control unit for defining and providing a focusing sequence on the at least one of the graphic representations by the optical device for providing a change of visibility of the graphic representations or of a part of the graphic representations by the detector and evaluating means for verifying a coincidence of the provided graphic representation or graphic representation sequence with corresponding data detected by the detector, wherein the apparatus is part of a system for reliably determining the position of an object regarding a relative movement between the object and a path, the system comprising: a detector attached to or integrated in the object, wherein the detector corresponds to the detector which detects the data of the graphic representation or graphic representation sequence used by the evaluating means, and at least one marker being located along the path, wherein the at least one marker is detected by the detector within its spatial detection range for determining the position of the object relative to the marker and wherein the apparatus provides the graphic representation or graphic representation sequence for detection by said detector. a sequence of graphic representations along an optical axis, wherein the graphic representations comprise a code, code sequence, binary code, bar code or data matrix code or a combination or superposition thereof, an optical device for focusing on at least one of the graphic representations, so that the at least one of the graphic representations is visible by a detector, a control unit for defining and providing a focusing sequence on the at least one of the graphic representations by the optical device for providing a change of visibility of the graphic representations or of a part of the graphic representations by the detector and evaluating means for verifying a coincidence of the provided graphic representation or graphic representation sequence with corresponding data detected by the detector, wherein the apparatus is part of a system for reliably determining the position of an object regarding a relative movement between the object and a path, the system comprising: a detector attached to or integrated in the object, wherein the detector corresponds to the detector which detects the data of the graphic representation or graphic representation sequence used by the evaluating means, and at least one marker being located along the path, wherein the at least one marker is detected by the detector within its spatial detection range for determining the position of the object relative to the marker and wherein the apparatus provides the graphic representation or graphic representation sequence for detection by said detector. a detector attached to or integrated in the object, wherein the detector corresponds to the detector which detects the data of the graphic representation or graphic representation sequence used by the evaluating means, and at least one marker being located along the path, wherein the at least one marker is detected by the detector within its spatial detection range for determining the position of the object relative to the marker and wherein the apparatus provides the graphic representation or graphic representation sequence for detection by said detector.