Navigation system for motor vehicles

• US 5,369,588 A
• Filed: 08/07/1992
• Issued: 11/29/1994
• Est. Priority Date: 08/09/1991
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Hayami, Katsuro, Goto, Hirofumi, Fujii, Yasushi, Yoshida, Chisato, Yokouchi, Kazuhiro
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/926,029
• Time in Patent Office: 844 Days
• Field of Search: 364/443, 364/444, 364/449, 73/178 R, 340/988, 340/990, 340/995
• US Class Current: 340/995.19
• CPC Class Codes: G01C 21/34 Route searching; Route guidance
• CPC Class Codes: G08G 1/096827 where the route is computed onboard
• CPC Class Codes: G08G 1/096838 where the user preferences are taken into account or the user selects one route out of a plurality
• CPC Class Codes: G08G 1/096844 where the complete route is dynamically recomputed based on new data
• CPC Class Codes: G08G 1/096866 where the complete route is shown to the driver

Abstract

A navigation system for a motor vehicle serves to guide the motor vehicle along an optimum route which includes bypass roads and side destinations desired by a driver but no road of high traffic congestion. When the motor vehicle deviates from the guidance route, an optimum route is again determined, starting from the current position of the motor vehicle. The navigation system includes a manipulating unit 1A for setting the desired bypass roads, side destinations and the final destination, a system controller 11 for setting the destination and the side destinations in terms of the coordinates on a map which are stored in a RAM unit together with information concerning the bypass roads and congested roads, a route extracting unit 6A for extracting an optimum route from a plurality of routes searched by a route search unit 5A on the basis of data read out from the RAM unit 14 and a route guidance controller for determining a distance deviation between the optimum route and the current position of the motor vehicle determined by a current position determining unit 7A. When the distance deviation exceeds a predetermined value, the system controller 11 commands the route search unit 5A and the optimum route extracting unit 6A to start again a new optimum route determining operation.

Claims

1. A navigation system for a motor vehicle, comprising:

manipulating means for designating at least a destination;

first storage means for storing information concerning a road network and road segments which constitute said road network;

current position detecting means for detecting a current position of said motor vehicle;

route search means for searching a plurality of routes which allows said motor vehicle to reach said destination from the current position thereof on the basis of said information available from said first storage means;

route extracting means for extracting an optimum route leading to said destination from said plurality of routes;

time lapse decision means for deciding whether or not a predetermined time period has elapsed after said optimum route was extracted, said predetermined time period starting at a point of time a system power supply was turned off; and

optimum route determination start commanding means for commanding said route search means and said route extracting means to start arithmetic determination of another optimum route, when it is decided by the time lapse decision means that said predetermined time period has elapsed.

2. The navigation system as claimed in claim 1 wherein the end of said predetermined time period is a point of time the system power supply is turned on.

3. A navigation system for a motor vehicle, comprising:

manipulating means for setting at least a destination and a starting time of said motor vehicle from a current position thereof;

first storage means for storing information concerning a road network and road segments which constitute said road network;

current position detecting means for detecting the current position of said motor vehicle;

route search means for searching a plurality of routes which allows said motor vehicle to reach said destination from the current position based on said information available from said first storage means;

route extracting means for extracting an optimum route from said plurality of routes;

optimum route determination start commanding means for commanding said route search means and said route extracting means to start arithmetic determination of said optimal route at the time of starting said motor vehicle and;

system power control means for maintaining a system power supply in a conducting state to, continue the arithmetic determination, even after a battery power supply of said motor vehicle is turned off and for turning said system power supply off after said optimal route has been extracted by said route extracting means.