A system and a method for determining the position of an elevator car, movably arranged in an elevator shaft of an elevator unit, use a 3D sensor, an evaluation unit in communication with the sensor, and a marking element actively emitting electromagnetic radiation. The sensor has a plurality of sensor cells and the evaluation unit uses measurement data received from the sensor to determine a distance from each sensor cell to a part of an object detected by the sensor. The sensor is arranged to detect the marking element and a region around the marking element as the object. The evaluation unit determines those sensor cells that detect the marking element and determines the position of the elevator car based on the determined distances to the detected object of those sensor cells and/or of sensor cells that are arranged in a region adjacent to those sensor cells.