Arcuate optical scanning for N-S movement in a map display navigational apparatus

摘要

A navigational apparatus for use in a piloted craft in which a map is displayed pictorially on a screen, representative of the terrain over which the craft is passing. The apparatus employs a moving film strip, a light source and known means to focus and project an image onto the screen. The light source is adapted for arcuate movement across the width of the film synchronously with an optical scanning device placed between the film and the screen and also adapted for arcuate movement so that N-S scanning of an individual film frame may be effected. E-W scanning of the film frame is effected by advancing the film in a suitable film transport. The film transport mechanism is suitably programmed to take into account a correction factor for the arcuate displacement of the N-S scanning device.