System and method for locating a travelling vehicle
First Claim
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1. A vehicle navigation system, which comprises:
- means for sensing a plurality of successive positions of said vehicle to create a sensed representation of a vehicle travel path;
means for storing a map of roads in a vicinity of said vehicle;
means for defining an actual vehicle travel path in said map;
means for matching said sensed representation of a vehicle travel path with said actual vehicle travel path; and
said means for matching including a plurality of fuzzy logic elements;
said fuzzy logic elements including;
a fuzzifier receiving said plurality of successive positions, and effective to produce an initial fuzzy set;
an inference engine receiving said initial fuzzy set, said map, and a set of inference rules and membership functions for producing a plurality of final fuzzy sets;
a defuzzifier effective for producing a set of crisp values from said final fuzzy sets; and
said crisp values being effective to determine a map-matched vehicle position.
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Abstract
A vehicle navigation system helps locate the vehicle on a road network by overcoming, through the use of fuzzy logic, the errors of positioning sensors and routing computers. In the system, sensors continually feed position coordinates to a processing unit that traces the vehicle'"'"'s path in a road database. Fuzzy logic-based reasoning is used to determine the most probable location of the vehicle, whether off- or on-road, thereby correcting errors in its raw path as sensed or computed.
106 Citations
4 Claims
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1. A vehicle navigation system, which comprises:
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means for sensing a plurality of successive positions of said vehicle to create a sensed representation of a vehicle travel path; means for storing a map of roads in a vicinity of said vehicle; means for defining an actual vehicle travel path in said map; means for matching said sensed representation of a vehicle travel path with said actual vehicle travel path; and said means for matching including a plurality of fuzzy logic elements; said fuzzy logic elements including; a fuzzifier receiving said plurality of successive positions, and effective to produce an initial fuzzy set; an inference engine receiving said initial fuzzy set, said map, and a set of inference rules and membership functions for producing a plurality of final fuzzy sets; a defuzzifier effective for producing a set of crisp values from said final fuzzy sets; and said crisp values being effective to determine a map-matched vehicle position. - View Dependent Claims (2)
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3. A method for locating a position of a vehicle comprising:
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sensing a plurality of successive positions of said vehicle to produce a stored representation of a vehicle travel path; comparing said stored representation with a plurality of vehicle travel paths in a map; the step of comparing including employing fuzzy logic to match said stored representation with a one of said plurality of vehicle travel paths, whereby a best matching path is chosen; and determining an actual position of said vehicle from said best matching path.
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4. A vehicle navigation system comprising:
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a plurality of positioning sensors to sense a plurality of successive positions of said vehicle; means for comparing said plurality of positions with a plurality of roads on a digitized map; fuzzy logic means for choosing a best fit from among a plurality of fits between said plurality of positions and said plurality of roads; and means, based on said best fit, for determining a vehicle present position on a one of said plurality of roads.
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Specification