Vehicular navigation system

• US 5,757,289 A
• Filed: 06/06/1995
• Issued: 05/26/1998
• Est. Priority Date: 09/14/1994
• Status: Expired due to Term

• Current Assignee: Aisin AW Company Limited (Aisin Corp.)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.)
• Inventors: Maekawa, Kazuteru, Nimura, Mitsuhiro, Nanba, Akimasa
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US08/466,193
• Time in Patent Office: 1,085 Days
• Field of Search: 340/995, 340/990, 340/988, 364/449.3, 364/444, 364/449.2, 364/449.4, 364/449.5, 73/178 R
• 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

A vehicular navigation system includes a central control unit which determines when a present position deviates from a searched route along which guidance is being provided from a starting point to a destination and determines whether or not the detected deviating present position is on a guidable road prior to re-searching the route and providing guidance based upon the re-searched route. A guidable road is a road upon which the navigation system contains sufficient map information and guide information for the navigation system to search a route and provide guidance. Additionally, system determines whether the vehicle has traveled a predetermined distance after re-search of the route prior to providing travel guidance based upon the re-searched route. Otherwise travel guidance continues to be provided based upon the previously searched route. A driver, after making a short deviation, may thus return to the previous route without travel guidance being interrupted by a re-searched route.

Claims

1. A vehicular navigation system comprising:

destination setting means for setting a destination;

storage means containing stored map information and stored guide information for guidable and unguidable roads, a guidable road being a road for which said storage means contains sufficient map information and guide information for the navigation system to include the road in searching to determine a route and to provide guidance for the road;

detecting means for detecting a present position and an advancing direction of a vehicle;

route searching means for searching, among said guidable roads, to determine a route from the present position to the destination on the basis of the stored map and guide information in said storage means;

guide means for providing travel guidance based upon the searched route and subsequently detected present positions on the searched route;

route deviation detecting means for detecting a deviation of travel from the searched route based on a subsequent detected present position deviating from the searched route;

guide road propriety deciding means, responsive to the route deviation detecting means detecting a deviation of travel, for deciding whether or not the detected deviating present position is on a guidable road; and

re-search means for re-searching the route based on the stored map and guidance information in said storage means on condition that the route deviation is detected by said route deviation detecting means and that it is decided by said guide road propriety deciding means that the detected deviating present position is on the guidable road so that said guide means provides guidance on the basis of the route which is researched by said re-search means.

2. A vehicular navigation system comprising:

destination setting means for setting a destination;

storage means containing stored map information and stored guide information;

detecting means for detecting a present position and an advancing direction of a vehicle;

route searching means for searching a route from the present position to the destination on the basis of the stored map and guide information in said storage means;

guide means for providing travel guidance based upon the searched route and subsequently detected present positions on the searched route;

route deviation detecting means for detecting a deviation of travel from the searched route based on a subsequent detected present position deviating from the searched route;

guide road propriety deciding means, responsive to the route deviation detecting means detecting a deviation of travel, for deciding whether or not the detected deviating present position is on a guidable road;

re-search means for re-searching the route on the basis of the stored map and guidance information in said storage means on condition that a deviation of travel is detected by said route deviation detecting means and that it is decided by said guide road propriety deciding means that the detected deviating present position is on a guidable road;

predetermined travel distance deciding means for deciding whether or not the vehicle has traveled a predetermined distance after the end of the route re-search by said re-search means; and

said guide means providing travel guidance based on the route which is re-searched by said re-search means, when the predetermined travel distance deciding means decides that the vehicle has traveled the predetermined distance, and providing travel guidance on the basis of the searched route, when the predetermined travel distance deciding means decides that the vehicle has not traveled the predetermined distance.

3. A vehicular navigation system comprising:

destination setting means for setting a destination;

storage means containing stored map information and stored guide information;

detecting means for detecting a present position and an advancing direction of a vehicle;

route searching means for searching a route from the present position to the destination on the basis of the stored map and guide information in said storage means;

guide means for providing travel guidance based upon the searched route and subsequently detected present positions on the searched route;

route deviation detecting means for detecting a deviation of travel from the searched route based on a subsequent detected present position deviating from the searched route;

guide road propriety deciding means, responsive to the route deviation detecting means detecting a deviation of travel, for deciding whether or not the detected deviating present position is on a guidable road;

predetermined travel distance deciding means for deciding whether or not the vehicle has traveled a predetermined distance after the end of a previous route re-search, responsive to detection of a deviation of travel from the searched route;

re-search means for newly re-searching the route on the basis of the stored map and guidance information in said storage means on condition that a deviation of travel is detected by said route deviation detecting means, on the condition that it is decided by said guide road propriety deciding means that the detected deviating present position is on a guidable road and, in the case of a previous route re-search, on the condition that the vehicle has travelled the predetermined distance;

said guide means providing travel guidance based on the route newly re-searched by said re-search means, in the case of the previous route re-search when the predetermined travel distance deciding means decides that the vehicle has traveled the predetermined distance, and providing travel guidance on the basis of the previous route re-search, when the predetermined travel distance deciding means decides that the vehicle has not traveled the predetermined distance.