JP3581893B2 - Navigation device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a navigation device that calculates a current position of a vehicle or the like, and particularly to a road candidate search area calculation device.
[0002]
[Prior art]
As a conventional navigation device, for example, there is one disclosed in “National Technical Report Vol. 40 No. 6 Dec. 1994“ Car navigation system (Ishikawa, et al.) ”.
[0003]
Hereinafter, an example of a conventional road candidate search area determination device of a vehicle-mounted navigation device will be described with reference to the drawings.
[0004]
FIG. 3 is a block diagram showing the configuration of a conventional road candidate search area determining apparatus. Reference numeral 21 denotes an absolute position calculating means for calculating an absolute position of a GPS receiver or the like and an estimated area, and reference numeral 23 denotes an absolute position for searching. Road candidate searching means for searching for a candidate on the road using the information of the existence estimation area.
[0005]
Next, the operation of the conventional navigation device configured as described above will be described.
[0006]
The road candidate searching means 23, which has received the information on the absolute position and the estimated position area calculated by the absolute position calculating means 21 such as a GPS receiver, uses the information on the absolute position and the estimated position area to store the information in the estimated position area. Search for a candidate position on a certain road.
[0007]
[Problems to be solved by the invention]
However, in the above-mentioned conventional configuration, when the arrangement of satellites such as GPS satellites for transmitting a signal for calculating an absolute position is poor, when the number of satellites that can be captured is small, or the Selective Availability is deteriorated. For example, when the existence estimation area becomes large, there is a problem that a road candidate more than a necessary number is searched (problem 1).
[0008]
Conversely, there is a problem that the required number of road candidates cannot be searched when the arrangement of the satellites is good or when the presence estimation area is small, such as when the number of satellites that can be captured is large (problem 2).
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a road candidate search area calculation device in a navigation device that solves the above-mentioned conventional problem and can always search for a required number of road candidates.
[0010]
[Means for Solving the Problems]
In order to solve the problems 1 and 2, the present invention provides a search for calculating an area for searching for a candidate on a road based on an absolute position calculated by an absolute position calculating means such as a GPS receiver and a presence estimation area. With this configuration, when the presence estimation area calculated by the absolute position calculation means such as a GPS receiver is larger than a predetermined threshold, the size of the area for searching for a road candidate is provided. Be fixed at the maximum value.
[0011]
Furthermore, by providing the search area calculation means, when the presence estimation area is smaller than a predetermined threshold, the size of the area for searching for a road candidate is fixed to a minimum value.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention, absolute mobile position and the absolute position calculating means for calculating the presence estimation region of the moving object, the moving object on a road on the basis of the absolute position absolute position and presence estimation region calculated by the calculation means And a search performed by the road candidate search means when the size of the existence estimation area calculated by the absolute position calculation means exceeds a preset threshold value. Search area calculation means for fixing the size of the area to a threshold value , and when the value of the existence estimation area is larger than a certain threshold value, the size of the area for searching for a road candidate is set to the maximum. Since the value can be fixed to the value, an effect of not searching for a required number of road candidates or more is exhibited.
[0013]
The search area calculating means, when the size of the presence estimation area calculated by the absolute position calculating means is larger than a predetermined maximum value of the threshold, the search area searched by the road candidate searching means. Is fixed to the maximum value of the threshold value. Further, the search area calculation means is searched by the road candidate search means when the size of the presence estimation area calculated by the absolute position calculation means is smaller than a minimum value of a preset threshold value. It is characterized in that the size of the search area is fixed to the minimum value of the threshold value, and has an effect that a required number of road candidates can be searched.
[0014]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
Figure 1 is a block diagram showing the configuration of a road candidate search area computing device in the vehicle navigation apparatus for explaining the implementation of the invention, 1 to calculate the presence estimation region and absolute position such as GPS receiver Absolute position calculation means 2 is a search area calculation means for calculating a search area and an absolute position for searching for a candidate on the road where the moving object exists from the absolute position and the estimated area of existence, and 3 is an absolute position for search. Road candidate search means for searching for a candidate on a road using the search area, and these constitute a road candidate search area calculation device 5.
[0016]
The road candidate search area calculation device 5, known vehicle speed pulse, relative distance change detecting means 6 such as an acceleration sensor 6, gyro-related relative angle change detecting means 7, and a recording medium on which digitized road information is recorded An on-vehicle navigation device includes a reproducing unit 9 for reproducing information from the recording medium 8, a drawing unit 10 for drawing a current location and a map of the surrounding area, and the like.
[0017]
Next, the operation of the road candidate search area calculation device configured as described above will be described with reference to the flowchart of FIG.
[0018]
First, the absolute position calculating means 1 calculates the absolute position of the moving object and its estimated area of existence (S1-1). The search area calculation means 2 uses the absolute position of the moving object calculated by the absolute position calculation means 1 and the information of the estimated area of existence of the moving object to obtain an absolute position for searching for a candidate position on the road where the moving object exists. The information of the search area is calculated (S1-2). At this time, if the presence estimation area is larger than the predetermined threshold A (YES in S1-3), the search area is fixed to the maximum value by the search area calculation means 2 (S1-4). If the area is smaller than the predetermined threshold B (YES in S1-5), the search area is fixed to the minimum value by the search area calculation means 2 (S1-6).
[0019]
The information on the absolute position and the search area calculated in this way is sent to the road candidate search means 3, and the road candidate search means 3 uses the information on the absolute position and the search area on the road of the moving body. (S1-7).
[0020]
As described above, when the value of the existence estimation area is larger than the predetermined threshold, the size of the area for searching for road candidates can be fixed to the maximum value. When the value of the existence estimation area is smaller than the predetermined threshold, the size of the area for searching for a road candidate can be fixed to the minimum value. Can search for candidates.
[0021]
【The invention's effect】
As described above, according to the road candidate search area calculation device in the navigation device of the present invention, by providing the search area calculation means or the present location road determination means, it is possible to prevent the search for more than the required number of road candidates. And a required number of road candidates can be searched.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a road candidate search area calculation device in a navigation device for explaining an embodiment of the present invention.
FIG. 2 is a flowchart of an operation in the road candidate search area calculation device of FIG. 1;
FIG. 3 is a block diagram showing a configuration of a road candidate search area determination device in a conventional in-vehicle navigation device .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Absolute position calculation means, 2 ... Search area calculation means, 3 ... Road candidate search means, 5 ... Road candidate search area calculation apparatus, 6 ... Relative distance change detection means, 7 ... Relative angle change detection means, 8 ... Recording medium , 9 ... reproduction means, 10 ... drawing means.

Claims (3)

Absolute position calculating means for calculating the absolute position of the moving body and the existence estimation area of the moving body ,
Road candidate searching means for searching for a candidate position on the road of the moving object based on the absolute position and the existence estimation area calculated by the absolute position calculating means ,
A search for fixing the size of the search area searched by the road candidate search means to a threshold value when the size of the presence estimation area calculated by the absolute position calculation means exceeds a preset threshold value Area calculation means;
Navigation equipment, characterized in that it comprises a. The search area calculating means , when the size of the presence estimation area calculated by the absolute position calculating means is larger than a predetermined maximum value of the threshold, the search area searched by the road candidate searching means. navigation equipment according to claim 1 wherein the magnitude of the said that you fixed to the maximum value of the threshold. The search area calculating means, when the size of the existence estimation area calculated by the absolute position calculating means is smaller than a preset minimum value of the threshold value, the search area searched by the road candidate searching means. claim 1 or claim 2 navigation equipment according to, characterized in that to fix the size of the minimum value of the threshold.

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