Route search and navigation apparatus and storage medium storing computer programs for navigation processing with travel difficulty by-pass

• US 6,101,443 A
• Filed: 04/08/1998
• Issued: 08/08/2000
• Est. Priority Date: 04/08/1997
• Status: Expired due to Term

• Current Assignee: Aisin AW Company Limited (Aisin Corp.)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.)
• Inventors: Kato, Shinichi, Mutsuga, Katsuhiko
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US09/056,786
• Time in Patent Office: 853 Days
• Field of Search: 701/210, 701/209, 701/211, 701/208, 340/995, 340/905, 342/451
• 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
• CPC Class Codes: G08G 1/096827 where the route is computed onboard
• CPC Class Codes: G08G 1/096844 where the complete route is dynamically recomputed based on new data
• CPC Class Codes: G08G 1/096861 where the immediate route instructions are output to the driver, e.g. arrow signs for next turn
• CPC Class Codes: G08G 1/096872 where instructions are given per voice

Abstract

The present invention prevents execution of a detour route search, responsive to and in accordance with received VICS data, where certain conditions are not met. To this end, the system of the invention calculates a time RT1 required for a vehicle to move from its present location to a first point where the vehicle must turn to the right or left to follow a previously determined guidance route and also calculates a time CT required to conduct a route re-search based on the received VICS data. If RT1≦CT the system then performs a route re-search based on the received VICS data. On the other hand, if RT1<CT execution of the route re-search is prohibited.

Claims

1. A route search apparatus comprising:

search means for searching a database to determine a guidance route;

a receiver for receiving information as to an impedance to travel on a road within a local area;

present location detection means for detecting the present location of the apparatus;

first comparison means for comparing the received information, inclusive of location of an impedance to travel, with said guidance route to determine if the impedence to travel is located ahead on the guidance route;

search estimation means, responsive to a determination that the location of the impedence to travel is located ahead on the guidance route, for determining a necessary time or distance required for a new route search to determine a new guidance route by-passing the impedence to travel and for preparation to initiate guidance based on the new guidance route;

prediction means for determining a predicted travel time or predicted travel distance between the detected present location and a specified location in advance of the impedance to travel;

second comparison means for comparing the necessary time with the predicted travel time or the necessary distance with the predicted travel distance; and

judgement means for deciding, based on the comparison by said second comparison means, whether or not the new route search is to be conducted.

2. The route search apparatus according to claim 1 further comprising override means for determining whether or not the impedence to travel is an impasse and for commanding the new route search if determined to be an impasse, thus overriding any decision by said judgement means that a new route search is not to be conducted.

3. A navigation apparatus for a vehicle comprising:

present position detection means for detecting present position of the vehicle;

a receiver for receiving road traffic information;

route search means for searching a database to determine a route leading to a destination;

necessary time calculation means for calculating time required for a new route search performed in accordance with the road traffic information received by said road traffic information reception means to determine a new guidance route and for preparation to initiate guidance for the new guidance route;

predictive time calculation means for calculating a predicted time required for the vehicle to arrive at a specified location in advance of a road branch in the direction of forward travel by the vehicle;

comparison means for comparing said necessary time with said predicted time; and

judgment means, responsive to said comparison, for judging whether or not the new route search is to be conducted.

4. The navigation apparatus according to claim 3 further comprising means for determining if the received road traffic information includes location of an impedence to travel, for determining if the location of an impedence to travel lies ahead and on the guidance route and for commanding the new route search responsive to a determination that an impedence to travel is located ahead on the guidance route.

5. The navigation apparatus according to claim 3 wherein said specified location is a location wherein a change of course is to be made to start travel of the new guidance route.

6. A medium storing therein a computer program for navigation of a vehicle, the program including:

calculating a necessary time for execution of a route search, in accordance with updated road traffic information received from a source remote from the vehicle, to determine a new guidance route and for preparation to initiate guidance along the new guidance route;

calculating a predicted time when the vehicle is expected to reach a travel direction change point leading to the new guidance route;

comparing the predicted time with the necessary time; and

executing the route search in accordance with results of the comparison.

7. The medium according to claim 6 wherein the program further comprises determining whether or not said road traffic information includes information as to an impedence to travel and whether or not the impedence to travel is located ahead and on a guidance route presently travelled and initiating the new route search responsive to a determination of an impedence to travel ahead on the presently travelled guidance route.

8. A navigation apparatus for a vehicle comprising:

present position detection means for detecting the present location of the vehicle;

a receiver for receiving road traffic information;

route search means for searching to determine a guidance route leading to a destination;

necessary time calculation means for calculating time required for a new route search, performed in response to receipt of the road traffic information, for determination of a new guidance route and for preparation to initiate guidance for the new guidance route;

predictive time calculation means for calculating a predicted time required for the vehicle to reach a travel direction-change location in the forward direction at which the vehicle must to turn to follow the new guidance route;

comparison means for comparing said necessary time with said predicted time; and

judgment means responsive to said comparison, for judging whether or not the new route search is to be conducted.

9. The navigation apparatus according to claim 8 further comprising means for determining if the received road traffic information includes location of an impedence to travel, for determining if the location of an impedence to travel lies ahead and on the guidance route and for commanding the new route search responsive to a determination that an impedence to travel is located ahead on the guidance route.

10. The navigation apparatus according to claim 8 wherein said travel direction-change location is the starting point for the new guidance route.

11. A medium storing therein a computer program for navigation processing for use in a vehicle, the program comprising:

calculating a necessary time for a new route search for a new guidance route in accordance with road traffic information received by communication from a location remote from the vehicle and for preparation for start of guidance for the new guidance route;

calculating a predicted time when the vehicle is expected to reach a certain location in advance of a road branch;

comparing the predicted time with the necessary time for a determination of whether or not the new route search should be conducted.

12. The medium according to claim 11 wherein the program further comprises determining whether or not said road traffic information includes information as to an impedence to travel and whether or not the impedence to travel is located ahead and on a guidance route presently travelled and initiating the new route search responsive to a determination of an impedence to travel ahead on the presently travelled guidance route.

13. The medium according to claim 11 wherein said certain location is the location where a guidance information message is scheduled to start.

14. The medium according to claim 11 wherein said road branch is an intersection where the vehicle is to turn in accordance with the new guidance route.