Model-based Threshold and Centerline Detection for Aircraft Positioning during Landing Approach

Aircraft navigation during landing approach is mostly supported by ground-based landing systems in commercial aviation, which cause high installation and maintenance costs. Nevertheless the final sequence of the flight before touchdown is mostly performed by the pilot manually, because of the high requirements on accuracy and integrity. Only a few landing systems can fulfill these requirements during the last 200 ft above ground. The current work presents a further development of an optical positioning system to be deployed below 200 ft and on ground after touchdown in order to be used as an additional source for positioning information. The system is capable of visual 3D positioning of the aircraft relative to the runway. Algorithms for threshold marking and centerline detection as well as lateral position calculation during rollout are presented. The system is evaluated during flight trials performed with the research aircraft Dornier Do 128-6.