In-car navigation apparatus
First Claim
1. An in-car navigation apparatus comprising:
- a map database storing digital map data composed of at least two ranks different in degree of road detail; and
searching means for searching a route from an appointed starting point to a destination through which a moving body should travel by means of a heuristic algorithm by changing a relative weight of a heuristic term of an evaluation function in accordance with said ranks of the digital map data stored in said map database.
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Accused Products
Abstract
An in-car navigation apparatus capable of searching an optimal or a quasi-optimal route always, and further capable of shortening the waiting time until a route is obtained, has an operating section which receives a starting point, a destination and searching conditions for searching from a handling section to read digital map data to be used for searching from the map database section of the apparatus. The operating section holds a plurality of weighting factors of each heuristic term to be used in an evaluation function or computing formulae to be used for the evaluation function, and searches an optimal or a quasi-optimal route by selecting an appropriate one in accordance with the road conditions and the searching conditions of the map data read in when searching is performed.
52 Citations
19 Claims
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1. An in-car navigation apparatus comprising:
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a map database storing digital map data composed of at least two ranks different in degree of road detail; and searching means for searching a route from an appointed starting point to a destination through which a moving body should travel by means of a heuristic algorithm by changing a relative weight of a heuristic term of an evaluation function in accordance with said ranks of the digital map data stored in said map database.
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2. A navigation system for determining a route to be travelled by a moving body going from starting point S to destination point T, comprising:
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a map database containing a plurality of maps having different rank numbers; and an operating section for selecting one of said ranked maps from said map database and for determining a section of said route from point S to point T by calculating an evaluation value from an evaluation function f(n), said evaluation function f(n) including a calculated cost term g(n) and a heuristic term h(n), the weight of said heuristic term h(n) relative to said calculated cost term g(n) being set in accordance with the rank number of said selected map. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for navigating a route to be travelled by a moving body going from starting point S to destination point T, comprising the steps of:
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(a) storing in a database a plurality of maps having different rank numbers; (b) selecting one of said ranked maps from said map database; (c) determining a section of said route from point S to point T by calculating an evaluation value from an evaluation function f(n), said evaluation function f(n) including a calculated cost term g n) and a heuristic term h(n), the weight of said heuristic term h(n) relative to said calculated cost term g(n) being set in accordance with the rank number of said selected map; and (d) repeating said steps (b) and (c) until a desirable complete route from point S to point T is determined. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification