Navigation system
First Claim
1. A navigation system for a vehicle, the system including:
- a display unit for displaying a vehicle mark, which indicates a current position and a heading direction of the vehicle, and a vicinity map surrounding the vehicle mark;
a measurement unit for measuring a current position and a heading direction of the vehicle;
a swept path computation unit for computing a swept path based on the measured current position;
a map data storing unit for storing map data;
a map matching unit for performing a map matching process to determine a road on which the vehicle travels, by comparing the computed swept path with a shape of a road in vicinity of the measured current position; and
a display control unit for causing the display unit to display the vehicle mark and the vicinity map such that the vehicle mark is on a road on which the vehicle travels, whereinon condition that (i) the vehicle travels on an expressway and (ii) candidate roads in the map matching process include a main road of the expressway and a road in a service area branching from the main road, the map matching unit determines that the road in the service area is a road on which the vehicle travels when a difference between the measured heading direction and a traffic direction of the main road is equal to or greater than a predetermined value.
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Accused Products
Abstract
A service-area road that is a road in a service area such as a rest area or parking area of an expressway is determined to be a road on which a vehicle travels on when the following three conditions are satisfied. A first condition is satisfied when the vehicle travels in an expressway. A second condition is satisfied when a main road of the expressway and the service-area road are designated as candidate roads in map matching process. A third condition is satisfied when a difference between the heading direction of the vehicle and the traffic direction of the main road is equal to or greater than a predetermined value. Thus, it can be as promptly as possible determined that the vehicle is traveling on the service-area road, allowing the vehicle mark to be accurately displayed on the service-area road on the displayed map.
29 Citations
6 Claims
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1. A navigation system for a vehicle, the system including:
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a display unit for displaying a vehicle mark, which indicates a current position and a heading direction of the vehicle, and a vicinity map surrounding the vehicle mark; a measurement unit for measuring a current position and a heading direction of the vehicle; a swept path computation unit for computing a swept path based on the measured current position; a map data storing unit for storing map data; a map matching unit for performing a map matching process to determine a road on which the vehicle travels, by comparing the computed swept path with a shape of a road in vicinity of the measured current position; and a display control unit for causing the display unit to display the vehicle mark and the vicinity map such that the vehicle mark is on a road on which the vehicle travels, wherein on condition that (i) the vehicle travels on an expressway and (ii) candidate roads in the map matching process include a main road of the expressway and a road in a service area branching from the main road, the map matching unit determines that the road in the service area is a road on which the vehicle travels when a difference between the measured heading direction and a traffic direction of the main road is equal to or greater than a predetermined value. - View Dependent Claims (2, 3, 4)
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5. A navigation system in a vehicle for traveling an expressway including a main road and a service-area road in a service area ancillary to the expressway, the system comprising:
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means for measuring a position and a heading direction of the vehicle; means for computing a swept path based on the position; means for storing data on roads including the expressway; means for performing a direction determination as to whether or not a difference between the measured heading direction and a traffic direction of the main road exceeds a threshold value; means for map matching to determine that the service-area road is a travel road, which the vehicle travels on, when the direction determination is affirmed when the main road and the service-area road are designated as candidate roads based on the measured current position, the stored data, and the computed swept path; and means for displaying a mark of the vehicle on the determined travel road on a map surrounding the vehicle.
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6. A method of navigating in a vehicle for traveling an expressway including a main road and a service-area road in a service area ancillary to the expressway, the method comprising the steps of:
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storing data on roads including the expressway; measuring a position and a heading direction of the vehicle; computing a swept path based on the measured position; performing a direction determination as to whether or not a difference between the measured heading direction and a traffic direction of the main road exceeds a threshold value; map matching to determine that the service-area road is a travel road, which the vehicle travels on, when the direction determination is affirmed when the main road and the service-area road are designated as candidate roads based on the measured current position, the stored data, and the computed swept path; and displaying a mark of the vehicle on the determined travel road on a map surrounding the vehicle.
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Specification