Depiction of large angles of view in perspective flight guidance displays through the use of non-planar projections

摘要

Next to flight and system status or sensor data, synthetic vision systems visualize information stored in databases on board of the aircraft in an intuitive manner on flight deck displays. For example, through the three-dimensional depiction of terrain or traffic information on the primary flight display, the pilot's overall situational awareness can be optimized. Today's implementations typically create the image using a perspective projection onto a planar image plane. Commonly, azimuthal angles of view between 30° and about 90° are used for this projection, which significantly limits the peripheral viewing area. Using larger angles of view for the perspective projection leads to a steady increase of compression in the image center and stretches at the image borders. These problems of the depiction of large angles of view have been resolved through the use of a non-planar projection, which projects the image onto a non-planar surface. In order to depict this curved surface on the planar display plane, another projection has to be executed. The non-planar projection allows the depiction of objects on the PFD without length distortions for large angles of view. By depicting large angles of view in synthetic vision systems, elements of the peripheral viewing area can be visualized. Aircraft flying abeam the own aircraft or topographic features like mountain valleys located next to the current aircraft position can be presented to the pilot on the primary flight display. Test flights in a research simulator revealed a strong acceptance of the non-planar projection by the study group of professional pilots.