Fecha de publicación: 14/12/2022 Fuente: WIPO (eseential oils OR extracts) A relative position calculator (32) calculates relative position and attitude of a vehicle (1) based on images captured by an image capturing apparatus on the vehicle (1). An absolute position calculator (34) extracts a marker (4) from an image captured by the image capturing apparatus, and calculates absolute position and attitude of the vehicle (1), based on position and attitude of the one extracted marker (4). A corrector (36) calculates the corrected position and attitude, not using the absolute position and attitude calculated based on the position and attitude of the marker (4) when a difference or ratio of an apparent height and width of the marker (4) in the image is equal to or smaller than a threshold, but using the absolute position and attitude calculated based on the position and attitude of the marker (4) when the difference or ratio is larger than the threshold.