Navigation system for a vehicle

• US 5,774,073 A
• Filed: 06/06/1995
• Issued: 06/30/1998
• Est. Priority Date: 09/22/1994
• Status: Expired due to Fees

• Current Assignee: Aisin AW Company Limited (Aisin Corp.)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.)
• Inventors: Hiyokawa, Toyoji, Maekawa, Kazuteru, Kanemitsu, Hiroyuki
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US08/466,191
• Time in Patent Office: 1,120 Days
• Field of Search: 340/995, 340/990, 340/988, 364/449, 364/444, 701/208, 701/209, 701/210
• US Class Current: 340/995.21
• CPC Class Codes: G01C 21/3415 Dynamic re-routing, e.g. recalculating the route when the user deviates from calculated route or after detecting real-time traffic data or accidents

Abstract

The present invention provides a navigation system for guiding a driver along an optimum route by comparing a route with preference on the traveling direction of a vehicle with a route with no preference on the traveling direction thereof when the driver is guided from the current position thereof up to a destination. To search for a route, a first route with preference on the traveling direction of a vehicle is calculated (1) and then, a second route with no preference on the traveling direction thereof is calculated (2). An appropriate route is selected from found routes according to a predetermined setting condition (3) and displayed on screen. The setting condition includes comparison of distances of respective routes and time lengths required for traveling thereon, ease of traveling, width and type of roads, scenery and the like. In a case where distances of the respective routes, for example, are compared with each other, if the distance of the first route is longer than the second route by at least a predetermined value, the second route is displayed, and if the first route is not longer than the second route by at least the predetermined value, the first route is displayed.

Claims

1. A navigation system for providing route guidance to a destination in accordance with a preset route, comprising:

memory means for storing map information and guidance information;

current position detecting means for detecting current position of a vehicle and traveling direction thereof;

route search means for searching to determine a route from the detected current position to a destination on the basis of information stored in said memory means and for storing the determined route as the preset route;

route-off detecting means for determining whether the vehicle is off of the preset route on the basis of the result of the detecting of current position by said current position detecting means and information in said memory means;

re-search means for re-searching for a new route, from the detected current position to the destination, on the basis of information in said memory means responsive to a determination by said route-off detecting means that the vehicle is off the preset route, said re-search means including;

first route search means for searching for a first re-search route forward, in the detected traveling direction, from the detected current position of the vehicle;

second route search means for searching for a second re-search route without giving priority to the forward traveling direction of the vehicle; and

comparative determining means for determining a difference in distance between the first and second re-search routes and for selecting said second re-search route when the difference in distance between said first and second re-search routes is greater than a predetermined value, and for selecting said first re-search route when the difference is less than the predetermined value; and

guide means for providing guidance by reading guidance information from said memory means based on one of said preset and new routes.

2. The navigation system of claim 1 wherein said first and second routes each include return to said preset route.

3. A navigation system for providing route guidance to a destination in accordance with a preset route, comprising:

memory means for storing map information and guidance information;

current position detecting means for detecting current position of a vehicle and traveling direction thereof;

route determination means for searching to determine a route from the detected current position to a destination on the basis of information stored in said memory means and for storing the determined route as the preset route;

said route determination means including;

first route search means for searching for a first route forward, in the detected traveling direction, from the detected current position of the vehicle;

second route search means for searching for a second route without giving priority to the forward traveling direction of the vehicle;

comparative determining means for determining a difference in distance between said first and second routes, for selecting said second route when the difference in distance between said first and second routes is greater than a predetermined value, and for selecting said first route when the difference is less than the predetermined value; and

guide means for providing route guidance based on the determined route.

4. A navigation system for providing route guidance to a destination along a preset route, comprising:

storage means for storing map information and guidance information;

first detector means for detecting current position of a vehicle and travel direction thereof and for outputting a first signal indicative of the detected current position and travel direction;

route search means for searching to determine a route to the destination from the detected current position based on the information stored in said storage means and for storing the determined route as the preset route;

second detector means for detecting a deviation from the preset route, responsive to said first detection signal, by reference to information contained in said storage means, and for generating a second detection signal when the vehicle is detected to have deviated from the preset route;

re-search means, responsive to receipt of the second detection signal, for searching to determine a new route to the destination from the detected current position, based on the information stored in said storage means, said re-search means including;

first route search means for searching for a first route forward, in the detected travel direction, from the detected current position of the vehicle to the destination;

second route search means for searching for a second route from the detected current position to the destination without giving priority to the forward travel direction of the vehicle; and

comparison means for setting a distance as one criterion for use in selecting a route, for determining a difference between distance of said first route minus distance of said second route, for determining that said one criterion is satisfied when said difference between distance of said first route minus distance of said second route is at least a predetermined value, for setting another distance as another criterion, for determining that another criterion to be satisfied if distance between the detected current position and the destination is less than or equal to said another distance and, if said another criterion is not satisfied, for proceeding to determine if said one criterion is satisfied; and

guidance means for providing route guidance for one of the preset and first routes by reading from said storage means a corresponding part of the guidance information, said guidance means providing route guidance based on the first route when said another criterion is satisfied and providing route guidance based on the first route when said one criterion is not satisfied.

5. The navigation system of claim 4 wherein said first and second routes each include return to said preset route.

6. A navigation system for providing route guidance to a destination in accordance with a preset route, comprising:

memory means for storing map information and guidance information;

current position detecting means for detecting current position of a vehicle and traveling direction thereof;

route search means for searching to determine a route from the detected current position to a destination on the basis of information stored in said memory means and for storing the determined route as the preset route;

route-off detecting means for determining whether the vehicle is off of the preset route on the basis of the result of the detecting of current position by said current position detecting means and information in said memory means;

re-search means for re-searching for a new route, from the detected current position to the destination, on the basis of information in said memory means responsive to a determination by said route-off detecting means that the vehicle is of the preset route, said re-search means including;

first route search means for searching for a first re-search route forward, in the detected traveling direction, from the detected current position of the vehicle;

second route search means for searching for a second re-search route without giving priority to the forward traveling direction of the vehicle; and

comparative determining means for determining required travel time for the first and second re-search routes, for selecting said second re-search route when a difference between the required travel times for said first and second re-search routes is treater than a predetermined value, and for selecting said first re-search route when the difference is less than the predetermined value; and

guide means for providing guidance by reading guidance information from said memory means based on one of said preset and new routes.

7. A navigation system for providing route guidance to a destination in accordance with a preset route, comprising:

memory means for storing map information and guidance information;

current position detecting means for detecting current position of a vehicle and traveling direction thereof;

route determination means for searching to determine a route from the detected current position to a destination on the basis of information stored in said memory means and for storing the determined route as the preset route;

said route determination means including;

first route search means for searching for a first re-search route forward, in the detected traveling direction, from the detected current position of the vehicle;

second route search means for searching for a second re-search route without giving priority to the forward traveling direction of the vehicle;

comparative determining means for determining required travel times for said first and second routes, for selecting said second re-search route when a difference between the required travel times for said first and second re-search routes is greater than a predetermined value, and for selecting said first research route when the difference is less than the predetermined value; and

guide means for providing route guidance based on the determined route.