Road map display system with indications of a vehicle position and destination

Claim 1

A road map display system for an automotive vehicle comprising: a first memory storing map image data arranged in a map coordinate system having an x-axis and a y-axis; a first sensor for detecting the position of a vehicle in said map coordinate system and producing a first sensor signal representative of the detected vehicle position; a second sensor for detecting the direction of vehicle travel and producing a second signal representative of the angular offset between the detected direction and the axes of the map coordinate system; first means for determining the map coordinates of a destination and producing a third signal representative of the position of the determined destination; second means for determining the origin of a second coordinate system having an x-axis and a y-axis in accordance with both said first sensor signal and said third signal and aligning the y-axis of said second coordinate system parallel to the detected direction of travel; third means for transforming the coordinates of said map image data in said first memory to said second coordinate system; a second memory storing at least part of the map image data in the second coordinate system; and fourth means, incorporating a display screen, for displaying the map image data stored in said second memory and symbols representing the information indicated by said first, second, and third signals.

Claim 8

A method for displaying a road map with superimposed symbols representing the positions of a vehicle and its destination on a display screen, comprising the steps of: storing first map image data of said road map in a first coordinate system; detecting vehicle position and direction of travel in relation to said first coordinate system; inputting the location of the destination in terms of said first coordinate system; establishing a second coordinate system based on the determined vehicle position, direction of travel and the destination coordinates such that one axis of said second coordinate system lies parallel to the direction of travel and the origin thereof is centered on a point halfway between the vehicle position and the destination; transforming said first map image data with respect to said second coordinate system to obtain second map image data; and displaying said second map image data on said display screen in conjunction with symbols representing vehicle position and direction of travel and the destination.

Claim 9

A method for displaying a road map with superimposed symbols representing the positions of a vehicle and its destination on a display screen, comprising the steps of: storing first map image data of said road map in a first coordinate system; detecting vehicle position and direction of travel in relation to said first coordinate system; inputting the location of the destination in terms of said first coordinate system; establishing a second coordinate system based on the determined vehicle position, direction of travel and the destination coordinates such that one axis of said second coordinate system lies parallel to the direction of travel and the origin thereof is centered on a point halfway between the vehicle position and the destination; transforming said first map image data with respect to said second coordinate system to obtain second map image data; and displaying said second map image data on said display screen in conjunction with symbols representing vehicle position and direction of travel and the destination.

Claim 13

A method as set forth in any one of claims 7 to 10, which further includes a step for determining whether the transformed coordinates of the first map image data fall outside of a display screen and in such cases inhibiting updating of the display with the second map image data.