Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Traffic analysis or control of surface vehicle
Reexamination Certificate
1999-03-25
2001-02-20
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Traffic analysis or control of surface vehicle
C701S200000, C701S207000, C701S208000, C701S209000, C340S988000
Reexamination Certificate
active
06192312
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a program and method used to determine a position of an object, such a vehicle, that moves in a geographic region represented by a geographic database, and more particularly, the present invention relates to a program and method used in a navigation system installed in a vehicle to determine in real time a position of the vehicle relative to geographic data used by the navigation system.
In-vehicle navigation systems provide a variety of useful features to end users (i.e., the drivers and/or passengers of the vehicles in which the navigation systems are installed). Included among the features that are provided by some in-vehicle navigation systems are route calculation, route guidance, emergency roadside services, electronic yellow pages, and so on. In order to provide these kinds of features, in-vehicle navigation systems use geographic data. The geographic data may be stored in the vehicle in which the in-vehicle navigation system is installed or alternatively, some or all of the geographic data may be stored remotely and made available to the navigation system in the vehicle through a wireless communication system which may be part of the navigation system. The geographic data include information about features in a covered geographic region. The geographic data includes information about the location of roads, the speed limits along roads, turn restrictions at intersections, the names of roads, the address ranges along roads, the locations of points of interest, and so on.
Some of the features provided by in-vehicle navigation systems require that the position of the vehicle be determined. There are several considerations related to determining the position of the vehicle. For example, a GPS system may be used to obtain the geographic coordinates of the vehicle. However, the geographic coordinates only indicate the position of the vehicle relative to the surface of the earth. For some of the features provided by in-vehicle navigation systems, a means is required to determine the vehicle position relative to the road network which is represented by the geographic data used by the in-vehicle navigation system. In other words, if the vehicle is located on a road segment, a means is required to identify the road segment, and optionally the position and direction along the road segment. Once the vehicle position is determined relative to the road segments in the geographic area, programming in the in-vehicle navigation system can be used to provide various features, such as determining a route to a desired destination, providing maneuvering instructions for reaching the destination, identifying the closest restaurant or gas station relative to the vehicle position, displaying a map of the area around the vehicle, and so on.
Some of the features provided by in-vehicle navigation systems require that the vehicle position be updated continuously in real time as the vehicle is driven along roads in a geographic region. For example, in some navigation systems, a map display feature may continuously update a graphic display of a map of the area through which the vehicle is traveling on a display of the navigation system. Also, a route guidance function provided by some navigation systems may provide maneuvering instructions to the driver as the vehicle approaches the location at which the maneuver is required. These kinds of functions require that the data identifying the vehicle position be updated continuously or regularly as the vehicle moves in a geographic region.
There are prior methods for determining a vehicle position relative to the data in a geographic database. However, a need for an improved method continues to exist. For example, there is a need to determine a vehicle position relative to data in a geographic database with greater precision and accuracy than can be provided by some prior methods. Also, there is a need to determine a vehicle position relative to the data in a geographic database with a more efficient use of the computing resources of the in-vehicle navigation system. Accordingly, there is a need for an improved vehicle positioning program and method.
SUMMARY OF THE INVENTION
To address these and other objectives, the present invention comprises position determining programming and a method performed by the position determining programming. The position determining programming determines a position of an object, such as a vehicle, relative to a road network which is represented by data included in a geographic database that represents features in a geographic region that includes the road network. The position determining programming determines whether the vehicle is on or off the road network represented by the data in the geographic database and, if the vehicle is on the road network, the position determining programming identifies the position of the vehicle relative to the data that represents the road network. In performing these functions, the position determining programming determines a position density for selected road segments of the road network. The positioning determining programming determines this position density using data from sensors. The value of the position density at each point along these selected road segments represents the likelihood that the vehicle is located at that position. The position density is, at each point on the road network and for each sensor, multiplied with the likelihood of measuring the measured value(s).
When requested to identify the current vehicle position, the position determining programming first shifts the position density which had been determined for the prior request for the vehicle position by a distance along the road segments to which the prior position density had been associated to form an intermediate position density. The distance by which the prior position density is shifted is the distance that the vehicle has traveled since the prior request for a vehicle position had been made. In one embodiment, the position determining programming takes into account the error associated with the measurement of the distance traveled by a convolution of the error with the position density. After the prior position density has been shifted to form an intermediate position density, the data from the sensors is applied to the intermediate position density to form a new position density along the road segments. The location along these road segments at which the new position density is greatest is identified as the position of the vehicle.
According to another aspect, the position determining programming forms a layer in a multi-layered vehicle positioning tool program that also includes other layers, such as a sensor device layer that interfaces with the sensor devices and another layer that determines a position from a fusion of the outputs from the sensor device layer.
In another aspect, the position determining programming is part of a navigation system installed in a vehicle.
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Cuchlinski Jr. William A.
Donnelly Arthur D.
Kaplan Lawrence M.
Kozak Frank J.
Navigation Technologies Corp.
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