JP2004264220A - On-vehicle navigation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle navigation device not presenting a high-cost route (for example, a detour route) unnecessarily in consideration of existence of a cut line of a median strip when searching for the route. <P>SOLUTION: This on-vehicle navigation device for searching for the route from a prescribed starting place to a prescribed destination searches for the route in consideration of the cut line of the median strip, or determines necessity of consideration of the median strip based on prescribed information when searching for the route. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention generally relates to an in-vehicle navigation device that searches for a route from a predetermined departure point to a predetermined destination, and more particularly to an in-vehicle navigation device that searches for a route by appropriately considering the existence of a median strip as needed. .
[0002]
[Prior art]
An in-vehicle navigation device that searches and selects a route with the lowest cost (or a high evaluation value) from a predetermined departure point to a predetermined destination using road node information and link information, and presents it to a vehicle occupant has been developed. Are known.
[0003]
Here, the cost / evaluation value of the route is a measure for making it easier for the driver and / or the vehicle to travel on the route, and the easier the cost, the lower the cost of the route and the higher the evaluation value. Will be considered. This easiness is determined by taking factors such as the road width, the type of road (expressway, national road, general road, etc.), the number of right and left turns, etc. into the main parameter component of the travel distance.
[0004]
Conventionally, in a route search by such an in-vehicle navigation device, when it is known that a median strip exists at a road link closest to a destination in consideration of the existence of a median strip, for example, a left-hand traffic environment A technique for searching for and selecting a route to a destination so as to guide the route to approach while viewing the destination with the left hand is known below (for example, see Patent Document 1).
[0005]
This prior art will be described in detail with reference to the drawings. As shown in FIG. 1, when a predetermined destination is set, the in-vehicle navigation device refers to a map database recorded on a recording medium such as a CD-ROM or a DVD-ROM, and A vertical line is dropped on the road link that has been set, and the intersection is set as the final guide point.
[0006]
There are two approaches to the final guide point: a route approaching while viewing the destination on the left (hereinafter referred to as “left route”) and a route approaching while viewing the destination on the right (hereinafter “right route”). ).
[0007]
Here, it is assumed that the illustrated example is in a left-hand traffic environment, and that there is a median strip on a road link where a final guide point is set, as shown in FIG. You cannot enter the destination immediately.
[0008]
Therefore, if it is known that the median strip exists on the road link where the final guide point is set, for example, in a left-hand traffic environment, a right-handed route with lower cost (higher evaluation value) exists. However, in the above-described conventional technology, only the left-handed route that can surely enter the destination is targeted for the route search.
[0009]
[Patent Document 1]
JP-A-11-83520
[Problems to be solved by the invention]
However, as shown in FIG. 2B, there may be a cut in the median strip.
[0011]
Here, the break in the median strip is, in a broad sense, a portion where the median strip is discontinuous on one road link, and in a narrow sense, a vehicle traveling on the road is It is a part that can make a right / left turn (turn right in a left-hand traffic environment and left turn in a right-hand traffic environment) by using the cut.
[0012]
As shown in FIG. 2 (b), even if a median strip exists at the road link where the final guide point is set, if there is a break in the median strip near the final guide point, for example, left-hand traffic Under the environment, it is possible to approach the final guide point with the right-hand route and turn right into the destination.
[0013]
The above-described prior art determines only whether or not a median strip exists at a road link closest to a destination, and does not pay attention to such a break of the median strip.
[0014]
Therefore, according to the above-described prior art, even if the vehicle can enter the destination with either the left-handed route or the right-handed route as shown in FIG. 2B, for example, in a left-hand traffic environment, only the left-handed route is searched. As a result, the route with the lowest cost (high evaluation value) to the destination may not be selected and presented.
[0015]
The present invention has been made to solve such a problem, and a costly route (for example, a circuitous route) is unnecessarily selected / selected in consideration of the presence of a break in the median strip when searching for a route. A main object is to provide an in-vehicle navigation device that is not presented.
[0016]
[Means for Solving the Problems]
One embodiment of the present invention is an in-vehicle navigation device that searches for a route from a predetermined departure point to a predetermined destination, and searches for the above-mentioned route in consideration of a break in a median strip. Device.
[0017]
According to this aspect, in particular, when the median strip exists on the road link where the final guide point is set, if the median strip break exists near the final guide point, the existence of the median strip is particularly considered. The route with the lowest cost (highest evaluation value) from all possible routes can be selected and presented without special consideration of left / right attachment to the destination. Due to the existence of the route, a route with an unnecessarily high cost (low evaluation value) is not selected and presented.
[0018]
In addition, if there is no break in the median strip near the final guide point, a route that can surely enter the destination even if the route is a little expensive (left-handed route in a left-hand traffic environment, In a traffic environment, the right-hand route can be selected and presented, so that the convenience of the driver is not impaired.
[0019]
Another aspect of the present invention is an in-vehicle navigation device that searches for a route from a predetermined departure point to a predetermined destination, and determines whether or not it is necessary to consider a median strip when searching for the route. The in-vehicle navigation device is characterized in that a determination is made based on the information of the vehicle.
[0020]
In this aspect, the predetermined information includes, for example, a) information about a break of a median strip around the destination, b) information about a structure on a road around the destination (for example, a length of a road link near the destination). C) information about the facilities at the destination (eg, whether the destination is an underground facility, whether the destination is a facility of a size exceeding a predetermined scale) ), D) information on the positional accuracy of the destination on the map database, and the like.
[0021]
According to this aspect, at the time of the route search, for example, the various types of information described above are referred to, and the route search is performed in consideration of the existence of the median strip, that is, in consideration of the left / right attachment to the destination. Is determined, it is not necessary to select and present a path that is unnecessarily high in cost (low evaluation value).
[0022]
In this aspect, when it is determined that it is necessary to consider the median strip (in other words, right / left) when searching for a route, the route is searched in consideration of the median strip. If the evaluation value of the first route (e.g., the left route in the left-hand traffic environment) is smaller than the evaluation value of the second route (e.g., the right route) searched without considering the median strip (e.g., If the distance difference is greater than or equal to a threshold, a second route (eg, a right route) is selected in order to avoid selection and presentation of a first route (eg, a left route) that costs excessively. It may be the final search result.
[0023]
Conversely, if it is determined that there is no need to consider the median strip (in other words, right / left attached) when searching for a route, the search performed in consideration of the median strip is considered. If the evaluation value of the third route (for example, the left route in the left-hand traffic environment) is larger than the evaluation value of the fourth route (for example, the right route) searched without considering the median strip (for example, the distance). (If the difference is less than or equal to the threshold value), priority may be given to ensuring that the vehicle can enter the destination, and the third route (for example, the route on the left) may be used as the final search result.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the description of the present embodiment, it is assumed that the vehicle is in a left-hand traffic environment. However, as will be apparent to those skilled in the art from the foregoing description, the present invention may be practiced in a right-hand traffic environment.
[0025]
First, a configuration example of the vehicle-mounted navigation device according to the present embodiment will be schematically described with reference to FIG.
[0026]
The in-vehicle navigation device 300 according to the present embodiment includes a navigation control unit 301 that controls and manages the entire device 300, a vehicle position detection unit 302 such as a GPS receiver that detects the current position of the vehicle, and a vehicle occupant. An operation input unit 303 which is a user interface for setting a final destination and the like, and a display 304 for visually presenting the position of the vehicle and the searched route together with map data to the driver are provided.
[0027]
The in-vehicle navigation device 300 further has a map database 305. In the present embodiment, the map database 305 includes facility data 306, road link data 307, and city map data 308. The road link data 307 includes node information and link information necessary for a route search as in the related art. The city map data 308 is road data that also includes shape data of roads, buildings, structures on roads, and the like. The facility data 306 will be described later in detail.
[0028]
These data may be stored collectively on one recording medium (for example, CD-ROM, DVD-ROM, or the like), or may be stored separately on a plurality of recording media.
[0029]
Further, the contents of the map database 305 may be appropriately updated to the latest information via communication means (not shown).
[0030]
Next, the flow of the route search process according to the present embodiment will be described with reference to FIG.
[0031]
First, an occupant of the vehicle (usually a driver) inputs and sets a final destination to the apparatus via the operation input unit 303 (S401).
[0032]
Next, the position accuracy of the input and set final destination on the map data is detected. This means that if the accuracy of the position data held by the map database 305 is originally low for the set final destination, it is originally worth searching for a route by executing detailed processing in consideration of the subsequent median strip and its break. This is to determine that it is thin.
[0033]
Such information on the positional accuracy may be stored in the map database 305 in advance as a part of the facility data 306, or may be appropriately acquired from outside using communication. In addition, the position accuracy may be determined for each facility / building based on, for example, whether or not precise surveying has been performed on the position of a certain facility / building, or, for example, accurate surveying or aerial photography may be performed. The determination may be made for each predetermined area based on whether or not the area has been performed.
[0034]
Therefore, when the accuracy of the position data held in the map database 305 is lower than a predetermined threshold for the set final destination or a predetermined area to which the final destination belongs (“YES” in S402), the existence of the median strip is determined. The route to the final destination is searched without consideration and presented to the occupant (S413).
[0035]
On the other hand, if the accuracy of the map database 305 is relatively good ("NO" in S402), then, whether the location of the set final destination parking lot is known, that is, whether or not it is included in the map database 305; Is confirmed (S403). This is because the parking lot may be located at a remote place depending on the facility. When the final destination is close to a plurality of road links, the position of the parking lot here also includes information on which road link is provided with an entrance to the parking lot.
[0036]
If the set location of the parking lot at the final destination (for example, a distant location or an entrance location) is known ("YES" in S403), the location is set as the final destination. A route is searched (S404).
[0037]
If the case of the parking lot at the final destination is not known ("NO" in S403), then, it is determined whether or not the probability that the position of the final destination matches the position of the parking lot is high (S405). In this determination, the final destination is illuminated with the facility data 306, and it is determined from the attribute of the facility whether or not the parking lot is located away from the final destination. For example, in the light of the facility data 306, if the final destination is a facility in an underground mall, it can be determined that the probability that the parking lot is far from the facility is very high.
[0038]
If the position of the parking lot at the final destination is not known and the probability of being at the same location as the destination is not high (that is, the probability of being at a remote location is high) (“NO” in S405), The probability that you will be able to reach the parking lot even if you take the optimal route to the final destination by executing detailed processing taking into account the median strip and its breaks is low, so the final goal without considering the existence of the median strip The route to the ground is searched and presented to the occupant (S413).
[0039]
If the location of the known parking lot is set as the final destination (S404) or if it is determined that there is a high probability that the parking lot exists at the final destination ("YES" in S405), then the final destination It is determined whether or not a median strip exists on a road link close to (S406). The determination in this step (S406) is to confirm only the presence or absence of the median strip as in the past, and can be easily performed by, for example, setting a flag regarding the presence or absence of the median strip on each road link in advance. Can be determined.
[0040]
If the median strip does not exist ("NO" in S406), the most cost to the final guide point is taken into account without considering the median strip, that is, without considering the left / right approach to the final guide point. A route with a low score is searched and presented (S413).
[0041]
On the other hand, if the median strip exists at the road link closest to the final destination ("YES" in S406), then data indicating where the break exists in the median strip of the road link (hereinafter, " It is determined whether or not “interruption data” can be used (S407).
[0042]
This break data may be held in advance as a part of the map database 305, or may be appropriately acquired from outside using communication. Even in the former case, it is desirable that the data is appropriately updated using communication. In the latter case, the break data may be broadcast, for example, from a facility of a national or local government that manages the road, a satellite equipped with a camera, or a commercial facility having a median strip break on the road in front of the store. It is useful if information is provided.
[0043]
If the break data is held or can be acquired ("YES" in S407), the last guide point is illuminated with the break data, and it is determined whether or not there is a break in the median strip near the last guide point. (S410). If there is a break ("YES" in S410), the vehicle can enter the final destination by turning left or right, and therefore, the left / right of the approach to the final guide point is not considered without considering the median strip. The route with the lowest cost is searched and presented without consideration (S413). On the other hand, if there is no break ("NO" in S410), the vehicle cannot approach the final destination by a right turn even if approached by a right-handed route, and thereafter, a route search taking into account the existence of the median strip is performed. You.
[0044]
If the break data is not stored in advance and cannot be acquired ("NO" in S407), the probability that a break in the median strip exists near the final guide point is determined (S408). The specific contents of this determination processing will be described later in detail.
[0045]
As a result of this determination, when it is determined that there is a high probability that there is a break in the median strip near the final guide point ("YES" in S409), the cost to the final guide point on the left-hand route is the lowest (or evaluation). The route with the highest cost and the route with the lowest cost (or the highest evaluation value) to the final guide point in the right-attached route are searched for (S411).
[0046]
Next, a cost difference between the lowest cost left route and the lowest cost right route is calculated. Here, since there is a high probability that a break in the median strip exists at the final guide point, it is a rule that the route with the lowest cost should be searched and selected irrespective of whether it is right or left attached. However, the existence of the break is not certain.
[0047]
Therefore, in the present embodiment, the cost of the right-attached route is slightly lower than the cost of the left-attached route, not only when the cost of the left-attached route is lower, but also when the cost of the right-attached route is lower. If the difference is a degree (for example, a distance difference of several meters), priority is given to being able to enter the destination without fail, and a left-handed route is selected.
[0048]
Specifically, when the difference obtained by subtracting the cost of the left-handed route from the cost of the right-handed route calculated in S411 is less than a predetermined threshold (lower limit) (“YES” in S414), the left-handed route Is selected as the route with the lowest cost and presented to the occupant (S416). If the difference is equal to or larger than the lower limit ("NO" in S414), the right-appended route is selected and presented (S417).
[0049]
In the case where it is found from the break data that there is no break in the median strip at the final guide point ("NO" in S410), or in the case where it is determined by the determination that there is a high probability that no break exists ("NO" in S409). ) And S411, a route with the lowest cost (or high evaluation value) to the final guide point on the left route and a route with the lowest cost (or high evaluation value) to the final guide point on the right route. Are respectively searched (S412).
[0050]
Next, similarly, a cost difference between the lowest cost left-attached route and the lowest cost right-attached route is calculated. Here, since there is no or a low probability that there is a break in the median strip at the final guide point, search for the route with the lowest cost by limiting to the left-handed route so that the final destination can be surely entered by turning left. The principle is to choose.
[0051]
However, if the cost of a left-handed route is excessively high (for example, if a left-handed route is several kilometers detoured relative to a right-handed route), if only left-handed routes are always selected and presented, Impairs user convenience.
[0052]
Therefore, in the present embodiment, when the cost of the left-handed route is significantly higher than the cost of the right-handed route, the right-handed route is selected so as not to present an excessively detour route to the driver.
[0053]
Specifically, if the difference obtained by subtracting the cost of the left-handed route from the cost of the right-handed route calculated in S412 exceeds a predetermined threshold (upper limit) (“YES” in S415), the right-handed route Is selected as the route with the lowest cost and presented to the occupant (S417). If the difference is equal to or less than the upper limit value ("NO" in S415), the left attached route is selected and presented (S416).
[0054]
Next, the determination processing in S408 will be described with some specific examples.
[0055]
The first specific example is a method using city map data 308. The city map includes shapes such as buildings and structures on the road such as a median strip. Therefore, by superimposing the city map data 308 on the road link data 307 including the node information and the link information, it is possible to determine whether or not there is a break in the median strip at the final guide point.
[0056]
FIG. 5 shows an example of a case where city map data is superimposed on the road link data shown in FIG. In the case of the example shown in FIG. 5, since the final guide point (white circle) is located exactly at the break of the median strip, it can be determined that the probability that the break exists is high ("YES" in S409). Conversely, if the final guide point and the median strip shown in the city map overlap, it can be determined that the probability that a break exists is low ("NO" in S409).
[0057]
In the first specific example, when the accuracy of the city map data 308 is good, the existence of the break can be grasped almost accurately. Conversely, the accuracy of the determination according to the first specific example depends on the accuracy of the city map data. Therefore, the method according to the second specific example is to determine the presence of a break even when the accuracy of city map data is relatively poor.
[0058]
This second specific example is a method of calculating the ratio of the median strip to the road link length. As shown in FIG. 6, after the city map data is superimposed on the road link data as in FIG. 5, it is calculated based on the city map data from the link length (node to node) of the road link where the final guide point exists. Subtract half of the width of the intersection. This result is called a reference link length.
[0059]
Next, a ratio of how much the total distance (total length) of the median strip existing on the road link occupies the reference link length is calculated. This ratio is regarded as the probability that a median strip exists on the road link, and the remaining probability is defined as the probability that a break exists. For example, when a median strip exists at 80% of the reference link length, the probability that a break exists is considered to be 20%. As will be apparent to those skilled in the art, what percentage or more of this probability can be arbitrarily set to determine that the probability that a break exists near the final guide point is high.
[0060]
In this specific example, in consideration of the fact that the final guide point cannot exist on the intersection road, since the reference link length is used as the reference for calculating the ratio instead of the total length of the road link as described above, the determination can be performed with high accuracy. .
[0061]
In the second specific example, the ratio occupied by the median strip may be calculated and stored in advance when creating the map database.
[0062]
A third specific example of the determination processing in S408 is a method using the facility data 306. In this specific example, the final destination is illuminated with the facility data, and if the attribute indicates that the final destination is a facility having a size exceeding a predetermined scale, the country or local government that manages the road is also required by the facility. Considering the size, it is determined that there is a high possibility that a break is provided even if there is a median strip so that the vehicle can enter even when turning right.
[0063]
Here, the facility size means, for example, an arbitrary area such as a site area, the number of cars that can be accommodated in a parking lot, the number of people that can be accommodated in a facility, the total floor area of the facility, the daily sales and the number of people working in a commercial facility. It may be defined by an index. Further, such information on the size of the facility may be appropriately acquired from outside using communication.
[0064]
As described above, according to the present embodiment, when a median strip exists on a road link on which a final guide point is set, and a median strip break exists near the final guide point, the median strip is The lowest cost (highest evaluation value) route can be selected and presented from all conceivable routes without special consideration of existence, that is, without special consideration of left / right attachment to the destination. Due to the existence of the median strip, a route with an unnecessarily high cost (low evaluation value) is not selected and presented.
[0065]
If a median strip exists on the road link where the final guide point is set, even if data on the breaks in the median strip is not retained or acquired, the central Since it is possible to estimate the probability that a band break exists, a route with an unnecessarily high cost (low evaluation value) is not selected and presented due to the presence of the median strip.
[0066]
Further, even when the search is limited to the left-attached route in consideration of the existence of the median strip, it is possible to prevent a route that is excessively expensive from being selected and presented.
[0067]
Furthermore, if it is not certain that there will be a break in the median strip near the final guide point, and if the cost advantage of adopting a right-hand route is small, it is possible to reliably enter the final destination. Can select and present a route attached to the left.
[0068]
As will be apparent to those skilled in the art, in the description of the above-described embodiment, the description has been made on the assumption that the vehicle is in a left-hand traffic environment. However, as described above, the present invention is applicable to a right-hand traffic environment. It is possible. In that case, the expressions "left" / "right" appearing in the description of the above-described embodiment may be interchanged and read.
[0069]
【The invention's effect】
As described above, according to the present invention, in consideration of the existence of a break in the median strip at the time of a route search, an in-vehicle vehicle in which a costly route (for example, a detour route) is not unnecessarily presented. A navigation device can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an example of road link data.
FIG. 2 (a) is a schematic diagram showing a situation where there is no break in the median strip at the last guide point.
(B) It is a schematic diagram showing a situation where there is a break in the median strip at the last guide point.
FIG. 3 is a diagram schematically showing a configuration of a vehicle-mounted navigation device according to an embodiment of the present invention.
FIG. 4 is a flowchart illustrating a flow of a route search process performed by the on-vehicle navigation device according to the embodiment of the present invention.
FIG. 5 is a schematic diagram showing a state in which city map data is superimposed on road link data.
FIG. 6 is a schematic diagram showing how a reference link length is set.
[Explanation of symbols]
300 In-vehicle navigation device 301 Navigation control unit 302 Own vehicle position detection unit 303 Operation input unit 304 Display 305 Map database 306 Facility data 307 Road link data 308 City map data

Claims (11)

An in-vehicle navigation device that searches for a route from a predetermined departure point to a predetermined destination,
An in-vehicle navigation device, wherein the route is searched in consideration of a break in a median strip. An in-vehicle navigation device that searches for a route from a predetermined departure point to a predetermined destination,
An in-vehicle navigation device, which determines whether or not it is necessary to consider a median strip when searching for the route based on predetermined information. The in-vehicle navigation device according to claim 2,
An in-vehicle navigation device, wherein whether or not it is necessary to consider a median strip when searching for the route is determined based on information about a break in the median strip around the destination. The in-vehicle navigation device according to claim 2,
An in-vehicle navigation device, wherein whether or not it is necessary to consider a median strip when searching for the route is determined based on information about a structure on a road around the destination. The in-vehicle navigation device according to claim 4, wherein
The on-vehicle navigation device according to claim 1, wherein the information about the structure on the road around the destination is a ratio of a median strip to a length of a road link near the destination. The in-vehicle navigation device according to claim 2,
An in-vehicle navigation device, wherein whether or not it is necessary to consider a median strip when searching for the route is determined based on information on facilities at the destination. The in-vehicle navigation device according to claim 6, wherein
When the destination is an underground facility, it is determined that there is no need to consider a median strip when searching for the route. The in-vehicle navigation device according to claim 6, wherein
If the destination is a facility having a size exceeding a predetermined scale, it is determined that there is no need to consider a median strip when searching for the route. The in-vehicle navigation device according to claim 2,
An in-vehicle navigation device, wherein whether or not it is necessary to consider a median strip when searching for the route is determined based on information on the positional accuracy of the destination on a map database. An in-vehicle navigation device according to any one of claims 2 to 9,
When it is determined that it is necessary to consider the median strip when searching the route, the evaluation value of the first route searched in consideration of the median strip is searched without considering the median strip. If the evaluation value of the second route is smaller than the evaluation value of the second route, the second route is used as a search result. An in-vehicle navigation device according to any one of claims 2 to 9,
When it is determined that there is no need to consider the median when searching for the route, the evaluation value of the third route searched in consideration of the median is searched without considering the median. An on-vehicle navigation device, wherein the third route is used as a search result if the evaluation value is larger than the evaluated value of the fourth route by a predetermined degree.

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