Control of an image triggering system for taking aerial photographs in nadir alignment for an unmanned aircraft

Method for aerial image acquisition with an unmanned and controllable aircraft with a camera, in particular a drone, during a flight movement of the aircraft with continuous determination of a camera position and an orientation of an optical camera axis and acquisition of an aerial image series. For each aerial image (21a-b) of the aerial image series, the acquisition of the respective aerial image (21a-b) is triggered when the aircraft flies through a respective image trigger region (33), wherein the position of the respective image trigger region (33) is determined at least by a trigger position assigned to the respective image trigger region (33) in a flight plan, and is triggered depending on the orientation of the camera axis when flying through the respective image trigger region (33) with respect to meeting a defined maximum angular deviation relative to a predetermined spatial orientation.