Data processing: vehicles – navigation – and relative location – Navigation – Employing position determining equipment
Reexamination Certificate
2001-01-25
2002-04-02
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Navigation
Employing position determining equipment
C701S207000, C701S208000, C701S200000, C340S990000, C340S995190
Reexamination Certificate
active
06366852
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a navigation device which is mounted in a moving body and which guides a route from a present position to a destination.
2. Description of Related Art
Navigation devices which guide a route from a current position of an automobile to a destination while driving have been widely applied. In this type of navigation device, when a destination is set by a user, the device searches a preferred route from the current position to the destination. When the searched route is presented to a user, it is common to present the route in an “entire route format” in which a route from a geographical position, at which a destination is set, to the destination is displayed on the same screen by switching a map scale. Furthermore, a method is employed of displaying more detailed information about the route by scrolling the map display automatically or manually along the route by switching to a detailed map display with a large map scale ratio. In addition, a method of sequential display of guiding maps of intersections on the route forward of a current position, or a method of displaying the route schematically by main branching points on the display device are also known in the art. Furthermore, it is possible to execute the guiding operation by use of voice commands.
FIG. 1
is a block diagram showing a first conventional navigation device as disclosed in JP-A-5-297800. In the figure, reference numeral
1
denotes a touch switch for inputting a destination or the like,
2
is a vehicle speed sensor for detecting a vehicle speed,
3
is a bearing sensor for detecting a bearing,
4
is an external storage device for storing information displaying classes of roads connecting branching points or information displaying classes of branching point of roads and pre-stored map information data.
5
is a display device for displaying information regarding main points such as branching points which are on a route from the present position to the destination.
6
is a control device which searches a travel route of the vehicle based on an input signal from the bearing sensor
3
and the vehicle sensor
2
and an input signal from the switch
1
and which displays main branching points on the travel route in summary form on the display device
5
.
The operation of the first conventional navigation device will be described below.
Firstly, route searching is executed. The route searching is executed according to a Dijkstra method. Of the routes connecting the present position and the destination, the device searches a route passing along main roads in which there are few right or left turns and in which the names of intersections at which turns are made are known. The search is made on the basis of the map information data stored in the external storage device
4
.
After the route is searched, the number of nodes contained on the route is counted and it is determined whether the number of nodes is less than or equal to 10. When the number of nodes is less than or equal to 10, the display process is executed to display the searched route.
On the other hand, when there are more than 10 nodes, a summarizing process is applied to the nodes contained on the route in which they are summarized based on informational value of each node. The summarizing process entails deleting those nodes of low information value until the number of nodes contained on the route are less than or equal to 10. Thereafter, display processing is executed. Herein information value is a product of a turning coefficient, a name presence/absence coefficient and a node category coefficient. The node category coefficient is a fixed coefficient corresponding to categories of nodes such as expressway entrance/exit, tollway entrance/exit or national road intersection. The node name presence/absence coefficient is a fixed coefficient which corresponds to the presence or absence of a name of the node. The turning coefficient is a fixed coefficient which corresponds to the presence or absence of left or right turns.
In the display process, the name of the destination and present position, the name of main branching points on the route from the present position to the destination, the distance between each branching point, representative place names which indicate the direction of travel, and the names of roads which should be taken at branching points are displayed on the display device
5
.
FIG. 2
is a block diagram of a second conventional navigation device as disclosed in International Publication WO98/51995. In the figure, reference numeral
10
denotes a control means which performs control of the overall device and each type of calculation in the navigation device.
11
is a map information storage means which stores digitized map information data such as intersection data, road data and the like.
12
is a present position detection means which detects a present position of the moving body in which the navigation device is mounted.
13
is a route setting means which sets a route between two points on a map on the basis of map information data stored in the map information storage means
11
.
14
is a guide object intersection detection means which detects a guide object intersection to be guided on the route set by the route setting means
13
.
15
is a quantizing calculation means which quantizes the route of the moving body onto a schematic map displaying the characteristic features of the route.
16
is a display means which displays a route quantized by the quantizing calculation means with respect to a guide object intersection detected by the guide object intersection detection means
14
.
17
is a voice guide message generation means having a voice information storage means (not shown) which stores necessary words or phrases for guide messages as voice wave form data. The voice guide message generation means selects voice wave form data such as words or phrases for guide messages and generates such combinations as guide messages when a quantized route of the moving body is displayed on the display means
16
.
18
is a voice output means which notifies a user by voice commands of guide messages generated by the voice guide message generation means.
The operation of the second conventional navigation device will be described below.
FIG. 3
is a flowchart explaining the operation of the second conventional navigation device shown in FIG.
2
.
Firstly, in a step ST
1
, the route setting means
13
sets two points on the map on the basis of latitude and longitude from the map information data read from the map information storage means
11
and then sets a route between the two points using a general search algorithm on a network such as a Dijkstra method or the like.
Then, in a step ST
2
, the present position detection means
12
detects a present position (C
1
) of the moving body. In a step ST
3
, the flags FL
1
, FL
2
, FL
3
are respectively initialized to 0.
Then, in a step ST
4
, the guide object intersection detection means
14
extracts an intersection with, for example, more than three roads being connected to the intersection as a forward guide object intersection (C
2
). The intersection is an intersection on the route set by the route setting means
13
and, of the two geographical points set by the route setting means, the intersection is further forward than present position (C
1
) detected by the present position detection means
12
.
In the step ST
5
, the detection of the present position (C
1
) of the moving body is performed again by the present position detection means
12
and in a step ST
6
, a road distance (L
1
) between the present position (C
1
) of the moving body and the forward guide object intersection (C
2
) is calculated on the basis of map information data read from the map information storage means
11
.
Then, in a step ST
7
, further processing operations are selected in response to this distance (L
1
).
When the distance (L
1
) is greater than a predetermined reference distance (L
2
) (for example 1000 meters), t
Irie Takashi
Norimoto Masatsugu
Cuchlinski Jr. William A.
Marc-Coleman Marthey
Mitsubishi Denki & Kabushiki Kaisha
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