Abstract: The invention relates to a system for annotating car radar data, comprising: at least one radar arranged on a car for producing a radar image by means of radar measurement; at least one optical detection system arranged outside the car for producing a camera image; a segmentation unit, which is designed to subject a camera image produced by the optical detection system to semantic segmentation for forming a semantic grid in order to assign one of a plurality of object classes to the camera image pixel by pixel; a computing unit, which is designed to transfer the camera image and/or the radar image into a common coordinate system for co-registration; and an annotation unit, which is designed to carry out annotation of the radar image, in other words to allocate an object class to a radar target of the radar image, in such a way that the object class of the semantic grid of the co-registered camera image in which the radar target of the co-registered radar image is located is allocated to a particular radar tar