Navigation system for guiding a vehicle along a precomputed optimal route

• US 5,291,414 A
• Filed: 04/14/1992
• Issued: 03/01/1994
• Est. Priority Date: 04/14/1992
• Status: Expired due to Term

• Current Assignee: TomTom International BV (TomTom NV)
• Original Assignee: Zexel Corporation Diahatsu-Nissan Ikebukuro
• Inventors: Abe, Tatsuhiko, Tamai, Haruhisa
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/868,483
• Time in Patent Office: 686 Days
• Field of Search: 364/443, 364/444, 364/449, 73/178 R, 340/988, 340/990, 340/995
• US Class Current: 701/210
• 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

When a vehicle has deviated from a computer-determined optimal route from a starting point to a destination, a navigation system warns the vehicle driver that he is off the optimal route, picks an appropriate direction for continued travel, selects a new starting point, and computes a new optimal route from the new starting point to the destination. By selecting the new starting point based on the vehicle'"'"'s present location and the time to recompute a new optimal route, the system eliminates the necessity for a driver either to go back to the original optimal route, to recompute the optimal route by a manual operation, or to recompute a new optimal route more than once.

Claims

1. A vehicle navigation system, which comprises:

means for storing and retrieving map data;

first means for detecting a present location of a vehicle;

manually operated means for sending a command signal effective for commanding computation of a route;

means, responsive to said means for sending, for computing from said map data an optimal route for said vehicle from a starting point to a destination;

means for guiding said vehicle along said optimal route;

second means for detecting a deviation of said vehicle from said optimal route;

said second detecting means effective to signal said deviation;

means for displaying information effective to indicate that said vehicle is off said optimal route when said second means for detecting signals said deviation;

said means for computing effective to recompute said optimal route, in response to a deviation signal from said second means for detecting when said deviation is detected;

means for selecting a new starting point for said recomputed optimal route; and

said new starting point being selected to be forward of said present location of said vehicle at a distance which is sufficient to ensure that a recomputation of said optimal route is completed before said vehicle arrives at said new starting point.

2. A vehicle navigation system as in claim 1, wherein said means for storing and retrieving includes a remote computer database.

3. A vehicle navigation system as in claim 1, wherein said means for computing includes a microcomputer.

4. A vehicle navigation system as in claim 1, wherein said first detecting means includes in combination a shaft sensor and a terrestrial magnetism sensor.

5. A vehicle navigation system as in claim 1, wherein said second detecting means includes in combination a shaft sensor, a terrestrial magnetism sensor, and a microcomputer.

6. A vehicle navigation system as in claim 1, wherein said means for guiding includes a microcomputer.

7. A vehicle navigation system as in claim 1, wherein said means for selecting includes a microcomputer.

8. A vehicle navigation system as in claim 1, wherein said means for displaying includes a CRT.

9. A vehicle navigation system as in claim 1, wherein said means for displaying includes an LCD.

10. A vehicle navigation system as in claim 1, wherein said means for sending includes a touch-screen switch.

11. A vehicle navigation system, which comprises:

a CD ROM for storing and retrieving map data;

a manually operated touch-screen switch effective to send a signal for commanding computation of a route;

a shaft sensor;

a terrestrial magnetism sensor;

said shaft sensor and said terrestrial magnetism sensor sending signals that determine a present location of a vehicle;

a microcomputer;

said microcomputer including means for computing from said map data an optimal route for said vehicle from a starting point to a destination;

said microcomputer further including means for guiding said vehicle along said optimal route;

said microcomputer receiving said signals to detect a deviation of said vehicle from said optimal route;

said microcomputer including means for signalling said deviation;

a CRT display including means for indicating that said vehicle is off said optimal route when said microcomputer signals said deviation;

said microcomputer including means for recomputing said optimal route when said deviation is detected;

said microcomputer further including means for selecting a new starting point for said recomputed optimal route; and

said new starting point being selected to be forward of said present location of said vehicle at a distance which is sufficient to ensure that a recomputation of said optimal route is completed before said vehicle arrives at said new starting point.