Navigation device and guide route search method
First Claim
1. A navigation device comprising:
- a vehicle location detecting unit having a CPU, and configured to receive distance or speed information from one or more sensors;
a map data storage unit operatively coupled to the vehicle detecting unit and CPU to store map data, the map data divided into a plurality of hierarchical levels based on an amount of information about a road network, wherein the amount of information is greater at a lower level of the hierarchical levels than at a higher level of the hierarchical levels;
a first guide route search unit operatively coupled to the vehicle detecting unit and CPU, to search for a first guide route from a departure point to a destination point by using the map data of the lowest level corresponding to an area surrounding the departure point and the destination point, respectively, and using the map data of levels higher than the lowest level corresponding to an intermediate region outside the area surrounding the departure point and the destination point, respectively;
a partial route extracting unit operatively coupled to the vehicle detecting unit and CPU, to extract a first partial route from the first guide route, the first partial route having a ratio between a straight-line distance and a distance measured between nodes at opposite ends thereof being greater than a predetermined value, the partial route extracting unit further including;
a first node identifying unit configured to identify a first node that is closest to one end of the first guide route among nodes forming the first guide route, wherein levels of the map data are changed at the first node;
a second node identifying unit configured to identify a second node that is closest to the other end of the first guide route, wherein levels of the map data are changed at the second node, wherein the partial route extracting unit is configured to extract the first partial route from the higher search route formed by nodes between the first node and the second node;
a second guide route search unit operatively coupled to the vehicle detecting unit and CPU, to generate a second partial route by performing a route search between nodes at opposite ends of the first partial route using the map data including the lowest level;
a guide route setting unit operatively coupled to the vehicle detecting unit and CPU, to set an eventual guide route representing a second guide route formed by replacing the first partial route of the first guide route with the second partial route;
a node number determining unit operatively coupled to the vehicle detecting unit and CPU, to determine whether the number of nodes between the nodes at opposite ends of the first partial route is less than a predetermined number to facilitate the route search between the nodes at opposite ends of the first partial route by the second guide route search unit; and
a straight-line distance determining unit operatively coupled to the vehicle detecting unit and CPU, to determine whether the straight-line distance between nodes at opposite ends of the first partial route is shorter than a predetermined distance, and wherein, if the straight-line distance between the nodes at opposite ends of the first partial route is less than the predetermined distance, the second guide route search unit performs the route search between the nodes at opposite ends of the first partial route by using only the map data of the lowest level.
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Abstract
A navigation device and a guide route search method prevents searching for a detour route, and shortens the time required for setting an eventual guide route. A first partial route is extracted from a first guide route found in accordance with map data divided into three hierarchical levels, based on information about a road network. The first guide route is the route from the current location to a destination. A second partial route is obtained by performing a route search between the nodes at opposite ends of the first partial route, based on the map data containing the lowest level. A second guide route is obtained by replacing the first partial route in the first guide route with the second partial route, and is set as the eventual guide route.
16 Citations
14 Claims
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1. A navigation device comprising:
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a vehicle location detecting unit having a CPU, and configured to receive distance or speed information from one or more sensors; a map data storage unit operatively coupled to the vehicle detecting unit and CPU to store map data, the map data divided into a plurality of hierarchical levels based on an amount of information about a road network, wherein the amount of information is greater at a lower level of the hierarchical levels than at a higher level of the hierarchical levels; a first guide route search unit operatively coupled to the vehicle detecting unit and CPU, to search for a first guide route from a departure point to a destination point by using the map data of the lowest level corresponding to an area surrounding the departure point and the destination point, respectively, and using the map data of levels higher than the lowest level corresponding to an intermediate region outside the area surrounding the departure point and the destination point, respectively; a partial route extracting unit operatively coupled to the vehicle detecting unit and CPU, to extract a first partial route from the first guide route, the first partial route having a ratio between a straight-line distance and a distance measured between nodes at opposite ends thereof being greater than a predetermined value, the partial route extracting unit further including; a first node identifying unit configured to identify a first node that is closest to one end of the first guide route among nodes forming the first guide route, wherein levels of the map data are changed at the first node; a second node identifying unit configured to identify a second node that is closest to the other end of the first guide route, wherein levels of the map data are changed at the second node, wherein the partial route extracting unit is configured to extract the first partial route from the higher search route formed by nodes between the first node and the second node; a second guide route search unit operatively coupled to the vehicle detecting unit and CPU, to generate a second partial route by performing a route search between nodes at opposite ends of the first partial route using the map data including the lowest level; a guide route setting unit operatively coupled to the vehicle detecting unit and CPU, to set an eventual guide route representing a second guide route formed by replacing the first partial route of the first guide route with the second partial route; a node number determining unit operatively coupled to the vehicle detecting unit and CPU, to determine whether the number of nodes between the nodes at opposite ends of the first partial route is less than a predetermined number to facilitate the route search between the nodes at opposite ends of the first partial route by the second guide route search unit; and a straight-line distance determining unit operatively coupled to the vehicle detecting unit and CPU, to determine whether the straight-line distance between nodes at opposite ends of the first partial route is shorter than a predetermined distance, and wherein, if the straight-line distance between the nodes at opposite ends of the first partial route is less than the predetermined distance, the second guide route search unit performs the route search between the nodes at opposite ends of the first partial route by using only the map data of the lowest level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A guide route search method in a navigation device having a vehicle location detecting unit and CPU, and receiving distance or speed information from one or more sensors, the method comprising:
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storing map data, by a map data storage unit, the map data divided into a plurality of hierarchical levels based on an amount of information about a road network, wherein the amount of information is greater at a lower level of the hierarchical levels than at a higher level of the hierarchical levels; and searching, by a first guide route search unit operatively coupled to the vehicle detecting unit and CPU, for a first guide route from a departure point to a destination point by using the map data of the lowest level corresponding to an area surrounding the departure point and the destination point, respectively, and using the map data of levels higher than that of the lowest level, corresponding to an intermediate region outside the area surrounding the departure point and the destination point, respectively; extracting a first partial route from the first guide route, the first partial route having a ratio between a straight-line distance and a distance measured between nodes at opposite ends thereof being greater than a predetermined value, wherein extracting the first partial route further includes; identifying a first node that is closest to one end of the first guide route among nodes forming the first guide route, wherein levels of the map data are switched at the first node; identifying a second node that is closest to the other end of the first guide route, wherein levels of the map data are switched at the second node; and extracting the first partial route from the higher search route formed by nodes between the first node and the second node; generating a second partial route by performing a route search between nodes at opposite ends of the first partial route using the use of the map data including the lowest level; setting an eventual guide route representing a second guide route formed by replacing the first partial route of the first guide route with the second partial route; and determining, using a node number determining unit operatively coupled to the vehicle detecting unit and CPU, whether the number of nodes between the nodes at opposite ends of the first partial route is less than a predetermined number to facilitate the route search between the nodes at opposite ends of the first partial route; and determining, using a straight-line distance determining unit operatively coupled to the vehicle detecting unit and CPU, whether the straight-line distance between nodes at opposite ends of the first partial route is shorter than a predetermined distance, and wherein, if the straight-line distance between the nodes at opposite ends of the first partial route is less than the predetermined distance, the performing the route search between the nodes at opposite ends of the first partial route by using only the map data of the lowest level. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification