Method and apparatus for adjusting distance for generating maneuver instruction for navigation system

Abstract

A distance adjustment method and apparatus for a navigation system produces a maneuver instruction for an intersection at the most appropriate timing and location during the route guidance. The method includes the steps of: searching an upcoming intersection on the calculated route that requires the user to make a turn therein; retrieving data concerning the upcoming intersection from a map database; adjusting a final distance from a reference point of the intersection by evaluating the retrieved data concerning the intersection; and generating a maneuver instruction at a timing when the user has reached the adjusted final distance from the reference point of the intersection, thereby notifying the user to make a turning maneuver at the intersection.

1 . A distance adjustment method for a navigation system, comprising the following steps of:
 conducting a route guidance operation of the navigation system for guiding a user to a destination through a calculated route;   searching an upcoming intersection on the calculated route that requires the user to make a turn therein within a predetermined distance range ahead from a current position;   retrieving data concerning the upcoming intersection from a map database;   adjusting a final distance from a reference point of the intersection by evaluating the retrieved data concerning the intersection; and   generating a maneuver instruction at a timing when the user has reached the adjusted final distance from the reference point of the intersection, thereby notifying the user to make a turning maneuver at the intersection.   
   
   
       2 . A distance adjustment method for a navigation system as defined in  claim 1 , wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection. 
   
   
       3 . A distance adjustment method for a navigation system as defined in  claim 1 , wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection with use of the retrieved data concerning the intersection. 
   
   
       4 . A distance adjustment method for a navigation system as defined in  claim 1 , wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection and a width of each lane with use of the retrieved data concerning the intersection. 
   
   
       5 . A distance adjustment method for a navigation system as defined in  claim 1 , further comprising a step of retrieving a reference distance from the reference point of the intersection, a step of obtaining an adjusted distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection, and a step of combining the reference distance and the adjusted distance to obtain the final distance. 
   
   
       6 . A distance adjustment method for a navigation system as defined in  claim 5 , wherein said step of obtaining the adjusted distance includes a step of detecting a number of lanes involved in the intersection and a width of each lane from the retrieved data, and a step of multiplying the number of lanes and the width of the lane. 
   
   
       7 . A distance adjustment method for a navigation system as defined in  claim 1 , further comprising a step of retrieving a reference distance from the reference point of the intersection, and a step of changing the reference distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection thereby determining the final distance from the reference point. 
   
   
       8 . A distance adjustment method for a navigation system as defined in  claim 7 , wherein said step of changing the reference distance for determining the final distance includes a step of incorporating a half width of a road segment where one road segment is involved in the intersection, and a step of either adding or subtracting the half width from the reference distance depending on the direction of the turning maneuver. 
   
   
       9 . A distance adjustment method for a navigation system as defined in  claim 7 , wherein said step of changing the reference distance for determining the final distance includes a step of incorporating a half width of a road segment where one road segment is involved in the intersection, a step of incorporating a half width of a center divider of the intersection, and a step of either adding or subtracting the half width of the road segment and the center divider from the reference distance depending on the direction of the turning maneuver. 
   
   
       10 . A distance adjustment method for a navigation system as defined in  claim 5 , wherein the reference distance is modified by evaluating various factors including a vehicle speed, traffic congestion, and weather condition. 
   
   
       11 . A distance adjustment apparatus for a navigation system, comprising:
 means for conducting a route guidance operation of the navigation system for guiding a user to a destination through a calculated route;   means for searching an upcoming intersection on the calculated route that requires the user to make a turn therein within a predetermined distance range ahead from a current position;   means for retrieving data concerning the upcoming intersection from a map database;   means for adjusting a final distance from a reference point of the intersection by evaluating the retrieved data concerning the intersection; and   means for generating a maneuver instruction at a timing when the user has reached the adjusted final distance from the reference point of the intersection, thereby notifying the user to make a turning maneuver at the intersection.   
   
   
       12 . A distance adjustment apparatus for a navigation system as defined in  claim 11 , wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection. 
   
   
       13 . A distance adjustment apparatus for a navigation system as defined in  claim 11 , wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection with use of the retrieved data concerning the intersection. 
   
   
       14 . A distance adjustment apparatus for a navigation system as defined in  claim 11 , wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection and a width of each lane with use of the retrieved data concerning the intersection. 
   
   
       15 . A distance adjustment apparatus for a navigation system as defined in  claim 11 , further comprising means for retrieving a reference distance from the reference point of the intersection, means for obtaining an adjusted distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection, and means for combining the reference distance and the adjusted distance to obtain the final distance. 
   
   
       16 . A distance adjustment apparatus for a navigation system as defined in  claim 15 , wherein said means for obtaining the adjusted distance includes means for detecting a number of lanes involved in the intersection and a width of each lane from the retrieved data, and means for multiplying the number of lanes and the width of the lane. 
   
   
       17 . A distance adjustment apparatus for a navigation system as defined in  claim 11 , further comprising means for retrieving a reference distance from the reference point of the intersection, and means for changing the reference distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection thereby determining the final distance from the reference point. 
   
   
       18 . A distance adjustment apparatus for a navigation system as defined in  claim 17 , wherein said means for changing the reference distance for determining the final distance includes means for incorporating a half width of a road segment where one road segment is involved in the intersection, and means for either adding or subtracting the half width from the reference distance depending on the direction of the turning maneuver. 
   
   
       19 . A distance adjustment apparatus for a navigation system as defined in  claim 17 , wherein said means of changing the reference distance for determining the final distance includes a step of incorporating a half width of a road segment where one road segment is involved in the intersection, means for incorporating a half width of a center divider of the intersection, and means for either adding or subtracting the half width of the road segment and the center divider from the reference distance depending on the direction of the turning maneuver. 
   
   
       20 . A distance adjustment apparatus for a navigation system as defined in  claim 15 , wherein the reference distance is modified by evaluating various factors including a vehicle speed, traffic congestion, and weather condition.