1. A device for determining an own position of an image-recording camera within an environment in which a plurality of structures are optically detectable, the device comprising: at least the image-recording camera, a measuring camera firmly mounted thereto in a known position and an evaluation unit, which is configured to determine an own position of the image-recording camera at least from the structures in a first image of the measuring camera, wherein the image-recording camera and the measuring camera are orientated such that they record at least partially a common section of the environment within which the structures are located are optically detectable by the image-recording camera in a first image and the measuring camera in a second image, and that the measuring camera is in connection with the evaluation unit, which is configured to continuously determine the own position of the image-recording camera at least from the structures in the environment that are respectively detected by the measuring camera, wherein the evaluation unit is further configured for locating the structures at least partially in the first image and for correcting the own position of the image-recording camera, which is determined from the second image, based on the position of the structures determined from the first image, wherein the evaluation unit is configured to correct the determined own position of the image-recording camera by searching, in the second image, for optically detectable structures, identifying the structures and carrying out an estimate of the position of the structures, whereupon the evaluation unit is configured to calculate a probable position of the structures in the first image, to search for the structures at the probable position in the first image, and to determine an actual position in the first image, whereupon the determined actual position of the structures in the first image is used by the evaluation unit for re-calculating the own position of the image-recording camera.