The invention provides a level sensor configured to determine a height level of a surface of a substrate, comprising a detection unit arranged to receive a measurement beam after reflection on the substrate, wherein the detection unit comprises an array of detection elements, wherein each detection element is arranged to receive a part of the measurement beam reflected on a measurement subarea of the measurement area, and is configured to provide a measurement signal based on the part of the measurement beam received by the respective detection element, and wherein the processing unit is configured to calculate, in dependence of a selected resolution at the measurement subarea, a height level of the measurement subarea, or to calculate a height level of a combination of multiple measurement subareas.