Route guidance on/off-route state filter
DCFirst Claim
1. A method for determining whether a vehicle is following a predetermined route on a map of roadways, said route comprising a selected portion of said roadways, the method comprising the steps of:
- receiving a set of position possibilities corresponding to possible positions of said vehicle on said roadways of said map;
verifying that the set of position possibilities are valid possibilities, thereby generating a first subset of position possibilities;
filtering the first subset of position possibilities without reference to said predetermined route to remove those least likely to correspond to an actual position of the vehicle, thereby generating a second subset of position possibilities;
filtering the second subset of position possibilities with reference to said predetermined route, thereby generating a set of remaining position possibilities;
selecting a current position from the remaining position possibilities; and
determining a route status of the vehicle based on said current position and said predetermined route.
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Abstract
The invention provides a route state filter for a vehicle route guidance system for improved tracking of vehicle position with respect to a preselected route. A set of position possibilities are derived by comparing a measured vehicle position to a database containing data representing a map of roads, the possibilities corresponding to possible positions on the roads within an error region around the measured position. A route guidance module receives the position possibilities, checks their validity and applies a filter to remove less likely possibilities. A current position is then selected from the remaining possibilities. An ON/OFF ROUTE status of the vehicle is determined by comparing the selected position with the selected route information in the database. A distance-based filter is utilized to provide improved continuity in the route status determination. The route status is then used to set the system operating mode, and instructional information such as maneuvers, distances, and warnings are communicated to the driver.
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Citations
18 Claims
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1. A method for determining whether a vehicle is following a predetermined route on a map of roadways, said route comprising a selected portion of said roadways, the method comprising the steps of:
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receiving a set of position possibilities corresponding to possible positions of said vehicle on said roadways of said map; verifying that the set of position possibilities are valid possibilities, thereby generating a first subset of position possibilities; filtering the first subset of position possibilities without reference to said predetermined route to remove those least likely to correspond to an actual position of the vehicle, thereby generating a second subset of position possibilities; filtering the second subset of position possibilities with reference to said predetermined route, thereby generating a set of remaining position possibilities; selecting a current position from the remaining position possibilities; and determining a route status of the vehicle based on said current position and said predetermined route. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A route guidance module in a vehicle navigation system for determining whether a vehicle is following a predetermined route on a map of roadways, said route comprising a selected portion of said roadways, said navigation system calculating a dead-reckoned position of said vehicle and further generating a set of position possibilities of said vehicle on said roadways, said route guidance module comprising:
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means for receiving said set of position possibilities; means for verifying that each of said position possibilities is a valid possibility, thereby generating a first subset of position possibilities; means for filtering the first subset of position possibilities without reference to said predetermined route to remove those least likely to correspond to an actual position of the vehicle, thereby generating a second subset of position possibilities; means for filtering the second subset of position possibilities with reference to said predetermined route, thereby generating a set of remaining position possibilities; means for selecting a current position from the remaining position possibilities; and means for determining a route status of the vehicle based on said current position and said predetermined route. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A route guidance system for determining whether a vehicle is following a predetermined route on a map of roadways, said route guidance system comprising:
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means for storing said map of roadways; means for reading a heading sensor and a distance sensor; means for calculating a dead-reckoned position using heading and distance readings; means for comparing said dead-reckoned position to said map of roadways; means for deriving a set of position possibilities, said position possibilities comprising positions on said roadways within an error region having said dead-reckoned position as its center; means for verifying that each of said position possibilities is a valid possibility, thereby generating a first subset of position possibilities; means for filtering the first subset of position possibilities without reference to said predetermined route to remove those least likely to correspond to actual position of the vehicle, thereby generating a second subset of position possibilities means for filtering the second subset of position possibilities with reference to said predetermined route, thereby generating a set of remaining position possibilities; means for selecting a current position from the remaining position possibilities; means for comparing said current position to said predetermined route to determine a route status of the vehicle, said route status comprising an ON ROUTE status or an OFF ROUTE status; and means for communicating said route status to a user of the route guidance system.
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Specification