Benefits and Challenges of Optical Positioning during Landing Approach

This paper presents results of a runway recognition based on line and contour features and performed by computer vision algorithms as part of an inertial navigation system aided by optical sensors. Runway recognition is performed during landing of an aircraft which is the most critical phase of a flight. Optical position calculation is the downstream process after runway recognition. The additional source of positioning helps to increase the redundancy of the navigation system, to reduce risks during critical flight phases and to diminish the dependency on ground-based navigation systems, such as ILS, since the optical system operates on-board of the aircraft. Furthermore, the accuracies of optical positioning are discussed and the influence of different approach angles on runway recognition is presented. The last part of the paper presents a method to merge the optically derived altitude with the inertial navigation solution based on GNSS and IMU. Consecutive challenges and benefits are discussed. Runway recognition and position estimation are performed during flight trials on-board of a twin-engine turboprop research aircraft Dornier 128-6. The interaction of the optical system with the inertial measurements is evaluated in simulations.