Passive “Radar-PAPI” Landing Aids for precision straight-in Approach and Landing in low visibility

Kurzfassung

Feasibility of a “Radar-PAPI” concept is examined that may act in low visibility like the visual PAPI landing aids in good visibility. This concept is built on three technological elements. First, the aircraft must be equipped with a forward-looking millimeter wave radar. Second, runway-marking retro-reflectors must be placed along the runway. Finally, another set of reflectors is needed to generate information on glide slope deviations. In a first field study, flight trials were completed to sample radar images. A subsequent low-fidelity part-task simulation was performed to answer the question as to how efficiently this kind of radar images can be utilized by pilots. Finally, an empirical study examined different options as to how to implement the Radar-PAPI concept in the cockpit. Results suggest that pilots learn the extraction of the visual cues from radar images surprisingly fast with the help of cue augmentation provided by retro-reflectors. Transformation of the usual plane-view display of the radar image to a three-dimensional perspective representation was associated with best pilot performance. In conclusion, ‘Radar-PAPI ‘ passive landing aids may be a feasible option implying a low level of automation to support low-visibility straight-in landings particularly for military operation.