Data processing: vehicles – navigation – and relative location – Navigation – Employing position determining equipment
Reexamination Certificate
2002-05-29
2004-03-09
Jeanglaude, Gertrude A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Navigation
Employing position determining equipment
C701S201000, C701S206000, C701S211000, C701S212000, C340S990000, C340S995100
Reexamination Certificate
active
06704648
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to providing route guidance with a navigation system, and more particularly, the present invention relates to an improved way to determine bearing data to provide guidance at intersections along a route with a navigation system.
Navigation systems are available that provide end users (such as drivers and passengers of the vehicles in which the navigation systems are installed) with various useful navigation-related features. Some navigation systems are able to determine an optimum route to travel by roads between locations in a geographic region. Using input from the end user, and optionally from equipment that can determine one's physical location (such as a GPS system), a navigation system can determine an optimum route (i.e., fastest, shortest, etc.) to travel from a starting location to a destination location in a geographic region. The navigation system can then provide the end user with information about the route in the form of guidance that identifies the driving maneuvers required to be taken by the end user to travel from the starting location to the destination location. The guidance may take the form of visual and/or audio instructions that are provided along the way as the end user is traveling the route. In some navigation systems, guidance about a required upcoming maneuver is provided as the location of the required maneuver is being approached. As an example, the guidance may indicate that the driver should keep to the left and make a sharp left turn at the upcoming intersection.
In order to provide these and other navigating functions, navigation systems use geographic data that represent physical features in a geographic region. The geographic data represent the roads and intersections in a geographic region and also may include information relating to the represented roads and intersections, such as turn restrictions at intersections, speed limits along the roads, street names of the various roads, address ranges along the roads, and so on. The geographic data are contained and organized in one or more databases.
In order to provide guidance about required maneuvers, an application in the navigation system evaluates data that relate to each intersection in a route to determine whether guidance should be provided at the intersection. If the navigation system application determines that guidance should be provided at an intersection, then the navigation system application also determines what kind of guidance to provide. A navigation system application that performs these functions is disclosed in U.S. Pat. No. 6,199,013, the entire disclosure of which is incorporated by reference herein.
There are various types of data that relate to an intersection in a route that can be evaluated by a navigation system application in order to determine what type of route guidance, if any, to provide. When evaluating an intersection along a route for this purpose, one of the factors to be considered is the size of the turn angle that is required in order to proceed through the intersection along the route. The size of the turn angle required to proceed through an intersection along a route is the angle made by the road segment leading into the intersection with the route segment leading out of the intersection. For example, if no turn is required at an intersection (i.e., the route proceeds straight through the intersection), the turn angle is approximately 180°. If the turn angle is approximately 180°, no guidance may be needed. On the other hand, if a driver is required to make a left turn at an intersection onto another street to continue along a route, the turn angle is approximately 90°. Under these circumstances, guidance in the form of audible or visual instructions may be needed.
One way to improve operation of a navigation system is to include data in the geographic database used by the navigation system to facilitate certain calculations required by applications in the navigation system. As an example, to facilitate determining the turn angle required to proceed through an intersection, the geographic database used by a navigation system can include data that indicate the bearing of a road segment at each of its endpoints. The bearing of a road segment at each of its endpoints indicates the angle made by the road segment at that endpoint with a predetermined direction (e.g., north).
FIGS. 1-10
illustrate examples of how bearing data can be represented in a geographic database used by a navigation system.
FIG. 1
is an illustration of a portion of a road network in a geographic area
100
. Four road segments
102
,
104
,
106
and
108
meet at an intersection
110
. The road segment
102
extends between the intersection
110
and the intersection
114
, the road segment
104
extends between the intersection
110
and the intersection
116
, the road segment
106
extends between the intersection
110
and the intersection
118
, and the road segment
108
extends between the intersection
110
and the intersection
112
.
FIG. 2
illustrates how these features are represented in a geographic database
120
. In the geographic database
120
, road segments are represented by road segment data records
121
and nodes (i.e., including intersections) are represented by node data records
130
. Road segment
102
is represented by the segment data record
122
, road segment
104
is represented by the segment data record
124
, road segment
106
is represented by the segment data record
126
, and road segment
108
is represented by the segment data record
128
. Likewise, each intersection is represented by a node data record. Intersection
110
is represented by the node data record
131
, intersection
112
is represented by the node data record
133
, intersection
114
is represented by the node data record
135
, intersection
116
is represented by the node data record
137
, and intersection
118
is represented by the node data record
139
. Other road segments and intersections in the geographic area
100
are represented by other data records in the geographic database
120
. In addition, the geographic database
120
may include other types of data
140
. These other types of data may represent points of interest, towns, cities, counties, states, countries, rivers, lakes, recreational areas, etc.
FIG. 3
is a block diagram that shows some of the components of the road segment data record
122
in the geographic database
120
. In
FIG. 3
, the road segment data record
122
includes data
150
that identify the end points of the road segment. The end points are identified by the node data records (i.e.,
131
and
135
) that represent the nodes at the end points of the represented road segment
102
. The road segment data record
122
also includes data
154
that indicate the successors at each end point. The successors at an end point of a road segment are those other road segments that are accessible via that end point. As shown in
FIG. 1
, the successors of the road segment
102
via the intersection
110
are the road segments
104
,
106
and
108
. Accordingly, the data record
122
(in
FIG. 3
) that represents the road segment
102
includes data
154
that identify these successors. In the data record
122
, the successors of the road segment
102
via the intersection
110
are identified by their corresponding road segment data records
124
,
126
, and
128
.
The road segment record
122
also includes data
160
and
162
that indicate the bearing at each endpoint of the road segment. As mentioned above, the bearing of a road segment at one of its end points indicates the angle made by the road segment at that endpoint with a predetermined direction, such as north.
FIG. 4
is a graphical representation of the geographic features shown in
FIG. 1
formed using the data representations of these features contained in the geographic database
120
of FIG.
2
.
FIG. 5
is a graphical representation of the road segment
102
in
FIG. 1
formed using the data record
122
in FIG.
Dayananda K C
Malingkas Richard
Naik Kirit
Jeanglaude Gertrude A.
Kaplan Lawrence M.
Kozak Frank J.
Navigation Technologies Corp.
Shotter Jon D.
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