Navigational device

Details Navigational device Navigational device

2001-02-09

2004-03-09

Camby, Richard M. (Department: 3661)

Data processing: vehicles, navigation, and relative location

Navigation

Employing position determining equipment

C701S213000

Reexamination Certificate

active

06704646

ABSTRACT:

BACKGROUND OF THE INVENTION
The invention relates to the field of motor vehicle navigation systems, and in particular to a modular navigation system that includes a display.
The main components of such a navigation unit or vehicle navigation system are a control unit for entering the starting point, intermediate destinations, and/or final destination; a data medium for navigation data (e.g., for information to display road maps); a navigation computer to plan the route and provide guidance to the destination; and a data processing unit to process the data into picture information The data processing unit generally includes a picture memory to store the picture information as well as a screen and a display unit to display road maps, position information, destination information, etc. The individual components communicate over a data bus, which in particular can also be an optical data bus. Such navigation units frequently also have a number of sensors to determine the vehicle position, its speed, orientation, etc.
U.S. Pat. No. 5,689,252 discloses a navigation unit that includes a microcontroller as its central unit. A data input device, a GPS signal receiver, a direction sensor, a distance sensor, and a traffic information receiver are connected to this microcontroller. A data memory that includes stored information about the road network, especially road maps, is also connected to the microcontroller. Data conducted from these components to the microcontroUer are made available to a navigation computer so that it can plan the route. The data calculated in this way are then displayed on a screen, which is likewise connected to the microcomputer. It should be noted that especially road map information cannot be displayed directly, but first must be transformed into picture information.
Newer systems give the user the capability of selecting the picture section by zoom or scroll functions. Furthermore, in such systems, the direction and motion of the vehicle is frequently shown on the road maps appearing on the screen. These socalled user demands (e.g., zoom or scroll functions) and system demands (e.g., vehicle motion) continuously change the display picture information, and must be continuously updated from suitable road map information.
The above arrangement of conventional navigation units or vehicle navigation systems allows road map information to be retrieved by the navigation computer individually for each displayed picture and to be put into the intermediate storage in the picture memory.
European Patent EP 0 306 088 A1 describes a new generation navigation unit. In this navigation unit, the individual components are connected to one another over a data bus. Such a linkage is customary in socalled linked driver information systems. The advantage of such linked driver information systems is that a nearly arbitrary number of individual components can be linked to one another over a data bus line. For example, a screen can be used not only to display navigation data, road maps, etc., but, for example, can also indicate a defect in the vehicle or the like.
The navigation unit described in European Patent EP 0 306 088 A1 includes a data bus, a data memory, in which a large number of road maps and navigation data is stored; a navigation computer to plan the route; and a data processing unit to process data into picture information. The data processing unit includes picture memory to store the picture information. The navigation unit also includes a screen, connected to the data processing unit, on which the picture information can be displayed, and a communication block with a control unit for entering the start position, intermediate destinations, and/or the final destination. The data memory, navigation computer, data processing and display are all connected to the data bus.
In such a system, the picture information of each road map is loaded individually into the picture memory. Such picture information is always transferred over the bus line. If the user wants to change, for example, the current screen display or if the motion of the vehicle requires the picture information to change continuously, the transfer of road map information from the data memory to the picture memory must occur continuously. For a screen display with sufficient picture refresh cycles, the data bus must have a large bandwidth, which generally is not available. Furthermore, the data bus is needed almost exclusively for transferring picture information, so that other information or data cannot be transferred or can be transferred only serially during the remaining interim times.
To elucidate this system, the above restrictions will be explained in terms of two examples:
In a first generation navigation unit, as shown in
FIG. 1
, the central unit is a navigation computer
1
. External information is conducted to this navigation computer
1
. In this example, the navigation computer obtains this information from a sensor block
10
, a data memory
2
, and a communication block
20
.
In this example, the sensor block
10
contains a direction sensor
12
and a position sensor
13
. The data memory
2
stores information about road networks This includes in particular information for displaying road maps, information about road signs, information about speed limits on the roads, and other navigation data. This data memory
2
generally is a CD-ROM, but any other storage medium is also conceivable, The data stored in the data memory
2
require updating at longer time intervals; in this example, the communication block
20
has the purpose of conducting to the navigation computer
1
navigation data which are constantly changing, Thus, the communication block
20
includes a control unit
21
for entering the destination and setting the screen functions, especially for selecting a road map section (zoom and/or scroll functions). Furthermore, a traffic data receiver
22
is also associated with this communication block
20
. For example, this receiver can receive current traffic information from various radio stations, and can process this information appropriately.
Data conducted from the sensor block
10
, the data memory
2
and the communication block to the navigation computer
1
are used by the navigation computer
1
to plan a route and to guide the driver to his destination. The road map display calculated in this way should then be conducted to a screen
4
. However, the road map information, created by the navigation computer
1
, cannot be displayed directly, but must first be converted into picture information by a suitable transformation. In present navigation systems or navigation units, a data processing unit
30
for this purpose is usually directly associated with the navigation computer
1
.
In the example of
FIG. 1
, the transformation of road map information and the picture information, which is performed in the data processing unit
30
, is accomplished by a transformation unit
31
. The road map information, which has been converted into picture information by the transformation unit
31
is then stored in the picture memory
32
and displayed on the screen
4
.
The data furnished by the sensor block
10
are needed by the navigation computer
1
for route planning and destination guidance, and to show the motion of the vehicle on the screen
4
. Furthermore, such navigation units usually make it possible for the user to select a road map section for viewing. For this purpose, the user can implement zoom and/or scroll functions. Such user requests are identified by the reference symbol B. Requests which are transmitted directly from the vehicle and on the basis of which the picture information changes are identified in this example as system requests S. Such a system request S preferably is issued on the basis of the data that are made available from the sensor block
10
. In the drawing, for the sake of clarity these system requests S and user requests B are conducted to the navigation computer
1
on the request line
6
.
FIG. 1
shows the arrangement of a first generation vehi

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