Navigation system having intersection routing using a road segment based database
First Claim
1. A method for routing to a destination, based on stored information about a network of roads, each road including one or more road segments, comprising the steps of:
- designating an intersection of at least two of the roads as the destination;
determining a starting location;
finding all of the road segments that connect to the designated intersection;
excluding from the found road segments any road segment not accessible from the designated intersection;
designating one of the remaining found road segments to be the destination road segment; and
searching for a route on the network of road segments from the starting location to the destination road segment, the route thereby being an ordered set of the road segments; and
indicating the route.
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Accused Products
Abstract
A route searching system for a vehicle navigation system for navigating on a road network, for use when the road network database is organized in terms of road segments and the destination is a road intersection. The destination road segment for a particular guided route is selected so that the destination road segment is accessible from the destination intersection. This is of benefit when the destination road segment is one permitting only one way travel, and thereby avoids selecting as the destination road segment a one way road permitting travel only into the destination intersection. This allows selection of an optimum route without dictating that the route pass through a one way segment leading only into the destination intersection. Another improvement is destination road segment filtering, whereby if a destination road segment is chosen such that travel on it is zero distance, then that destination road segment is deleted from the guided route, and instead the end of the previous road segment on the guided route is indicated as being the destination. This eliminates unnecessary instructions being given to the driver when he arrives at the destination intersection.
183 Citations
20 Claims
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1. A method for routing to a destination, based on stored information about a network of roads, each road including one or more road segments, comprising the steps of:
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designating an intersection of at least two of the roads as the destination; determining a starting location; finding all of the road segments that connect to the designated intersection; excluding from the found road segments any road segment not accessible from the designated intersection; designating one of the remaining found road segments to be the destination road segment; and searching for a route on the network of road segments from the starting location to the destination road segment, the route thereby being an ordered set of the road segments; and indicating the route. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Apparatus for routing to a destination, comprising:
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a memory storing information about a network of roads, each road including one or more road segments; means for designating an intersection of at least two of the roads as the destination; means for determining a starting location; means for finding all of the road segments that connect to the designated intersection; means for excluding from the found road segments any road segments not accessible from the designated intersection; means for designating one of the remaining found road segments to be the destination road segment; means for searching for the route on the network of road segments from the starting location to the destination road segment, the route thereby being an ordered set of the road segments; and means for indicating the route. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for routing to a destination, based on stored information about a network of roads, each road including one or more road segments, comprising the steps of:
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designating an intersection of at least two of the roads as the destination; determining a starting location; searching for a route on the network of road segments from the starting location to the destination intersection, the route thereby being an ordered set of the road segments; determining if a distance to the destination intersection on a last road segment in the ordered set is zero; only if the distance is zero, excluding the last road segment from the ordered set; and indicating the route as being the ordered set of road segments, excluding the excluded road segment. - View Dependent Claims (14, 15, 16)
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17. Apparatus for routing to a destination, comprising:
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a memory storing information about a network of roads, each road including one or more road segments; means for designating an intersection of at least two of the roads as the destination; means for determining a starting location; means for searching for a route on the network of road segments from the starting location to the destination intersection, the route thereby being an ordered set of the road segments; means for determining if a distance to the destination intersection on a last road segment in the ordered set is zero; means for excluding the last road segment from the ordered set only if the distance is zero; and means for indicating the route as being the ordered set of road segments, excluding the excluded road segment. - View Dependent Claims (18, 19, 20)
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Specification