Enroute vehicle guidance system with heads up display

Abstract

A positioning and navigation system for land vehicles features a simple and memory-conserving route entry method. Routes on maps can be specified by the junctions traversed by the route, so that entering only the junctions in memory uses much less space than prior art digital route storage systems which stored the coordinates of each point along the route. A trip progress information display shows the route vividly by using color or brightness contrast with the rest of the map. Additional direction of travel indications can be given, for example on a Head Up Display reflected off the inside of the windshield within the operator's field of view or by acoustic signals or speech-synthesized announcements. This results in particularly easy-to-follow guide to the driver or operator. Head-up displays on motor vehicles often have double images and interfering reflections on the windshield. To avoid these, arrangements of linear polarization filters or shutter foils are suggested, which have particularly high light transmission. Arrangements of filter plates on a combiner inside of the windshield are also advantageous.