Abstract: In a method or system in which an imaging element views navigation elements for e.g. navigation, the navigating elements may not be positioned optimally. Positions may exist in which the same angles exist from the imaging element to the same or similar navigating elements, whereby the positions are not unique. Navigation elements may then be repositioned, added or removed to make the positions unique.

Abstract: A method for obtaining a three-dimensional model of an inspection site, using a perception module, is disclosed. The perception module comprises a detection unit, e.g. comprising one or more cameras and/or a three-dimensional laser scanner, configured to obtain a three-dimensional image. At least one three-dimensional image is obtained by means of the detection unit. A three-dimensional model of surroundings of the perception module is created, based on the obtained three-dimensional image. The created three-dimensional model and a plan of the inspection site are compared and features of the created three-dimensional model and features of the plan of the inspection site are matched. A site-specific three-dimensional model of the inspection site is formed, based on the created three-dimensional model and the plan of the inspection site, and based on the comparison.