JP2001050743A - Road grade computing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate accurate computing of a forward road grade by using a conventional navigation device in a road grade computing apparatus. SOLUTION: Present position and traveling direction of an automobile are detected by an automobile position detection means 4a so as to convert coordinates of the automobile position into those on a map stored in a map information memory means 4b, and determine the present position and the traveling direction of the automobile. On the other hand, taking the automobile position as a traffic origin, a plurality of virtual points are set at predetermined distance intervals forwardly along a traveling road for the automobile by a road grade computing means 4d, while an elevation in a region wherein each virtual point is present is set as that for each virtual point on the basis of elevation information of an elevation information memory means 4e. And, a gradient between the automobile position and each virtual point is computed, while a forward road grade relative to the automobile is computed by averaging the gradients.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road gradient calculating device for calculating a road gradient ahead of a traveling road of a vehicle.

[0002]

2. Description of the Related Art In recent years, the current position of a vehicle such as an automobile is calculated by receiving radio waves from a plurality of artificial satellites.
2. Description of the Related Art Navigation systems (navigation devices) that are displayed on a road map on a display are widely used. In such a navigation system, a recording medium such as a CD ROM is generally used as software (navigation software), and map information such as road data is stored in the navigation software.

The road data is specifically managed by coordinate points, and roads are displayed by connecting the coordinate points with lines. Each coordinate point is managed by longitude and latitude, which are the X value and Y on rectangular coordinates (XY coordinates).
Has been replaced by the value. It should be noted that such navigation software is provided with not only XY coordinates but also height information, that is, Z coordinates for inputting altitude, but no particular data is currently input to these Z coordinates. At present, it is not possible to know the altitude or road gradient using only navigation software.

[0004] On the other hand, there is also a demand to be able to calculate the altitude and the road gradient of the own vehicle in addition to the own vehicle position information using such a navigation device. In response to such a demand, JP-A-9-304089 discloses a GP
A technique has been disclosed in which the altitude of the own vehicle is obtained from the own vehicle position of the navigation device using S and the mesh altitude data. Here, the mesh elevation data is elevation data provided by the Geospatial Information Authority of Japan, and can be obtained in the form of a recording medium such as a CD ROM, similarly to the navigation software. In this mesh elevation data, the map of the whole country is finely divided into small square areas each having a length of about 50 m or 10 m, and the elevation of the center of each area is stored.

[0005] Then, a map obtained from the navigation system is superimposed on this mesh elevation data,
The area where the current vehicle position is located is determined, and the elevation of the area where the current vehicle position exists is recognized as the elevation of the own vehicle. In addition, other than such a technique, a technique of obtaining a road gradient from elevation data of each coordinate point stored in the navigation software (Japanese Patent Laid-Open No. 10-2412),
A technique has been proposed in which a camera is attached to a vehicle and a road gradient is calculated based on image information obtained from the camera.

[0006]

However, in the technique disclosed in Japanese Patent Application Laid-Open No. 9-304089, the altitude of the vehicle is simply calculated, and the road gradient ahead is not determined. Also, even when trying to determine the gradient from the altitude data, the altitude of the current position of the vehicle can be obtained, but the road coordinates ahead of the vehicle cannot be determined unless the traveling road of the vehicle is determined, There was a problem that it was not possible to determine the road gradient.

Further, the technique disclosed in Japanese Patent Application Laid-Open No. 10-2412 has a problem that the road gradient cannot be calculated with high accuracy. That is, usually, the coordinate points of the road stored in the navigation device are set so as to correspond to the curve of the road (the coordinate interval is short on a curved road and the coordinate interval is long on a straight road). There is a problem in accuracy because it is not taken into account. In particular, there is a problem that a road gradient cannot be calculated with high accuracy because a coordinate interval becomes large on a straight road and altitude information is lost during that time.

Further, the technique of calculating the road gradient ahead by processing the image information of the camera has a problem that the calculation of the road gradient becomes unstable when the imaging conditions of the camera are poor, such as at night or in bad weather. . In addition to these techniques, JP-A-6-333197 discloses a technique in which slope information on a road is stored in a storage medium in advance, and a slope symbol is provided on a display based on the slope information. Although it is disclosed, there is currently no software that adds slope information to roads. Even if slope information is added to roads, the slope information of roads is enormous, so this is stored in a storage medium in advance. There is a problem that it requires a lot of labor to keep.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and has made it possible to easily and accurately calculate a road gradient ahead using a conventional navigation device.
It is an object to provide a road gradient calculating device.

[0010]

In the road gradient calculating apparatus according to the present invention, when the current position and the traveling direction of the own vehicle are detected by the own vehicle position detecting means, the coordinates of the own vehicle position are stored in the map information storing means. The current position and the traveling direction of the own vehicle are determined by being converted into the coordinates on the map. On the other hand, the road gradient calculating means sets a plurality of virtual points ahead of the own vehicle position along the traveling road of the own vehicle at intervals of a predetermined distance, and sets each virtual point based on the altitude information of the altitude information storage means. The elevation of the area where the virtual point exists is set as the elevation of each virtual point.

The gradient between the position of the vehicle and each virtual point is calculated, and the gradient of the road ahead of the vehicle is calculated by averaging the gradients. This makes it possible to easily and accurately calculate the road gradient ahead of the own vehicle.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a road gradient calculating apparatus according to an embodiment of the present invention;
FIG. 1 is a schematic functional block diagram showing the configuration of the main part, FIG. 2 is a schematic diagram for explaining the calculation method, and FIG. 3 is a flowchart for explaining an example of the operation.

[0013] As shown in FIG.
PS antenna 1, FM antenna 2, FM multiplex receiver 3,
Navigation body 4 and display (display means) 5
Is provided. The navigation body 4 includes a GPS receiver 4a as a vehicle position detecting means for detecting a current position and a traveling direction of the vehicle and a map information storing means for storing data of a plurality of coordinate points constituting a road. Navigation software 4b and the like are provided. The navigation software 4b is a recording medium such as a CD ROM storing map information such as road data. Further, the navigation software 4b may be provided outside the navigation body 4.

The radio wave from the artificial satellite received by the GPS antenna 1 is taken into the GPS receiver 4a, and the GPS receiver 4a determines the current position (latitude and longitude) of the vehicle based on the received radio wave. It is to be calculated. The GPS receiver 4a calculates the current traveling direction of the vehicle based on the position information calculated last time and the position information calculated this time, in addition to the current position of the vehicle.

The current position obtained by the GPS receiver 4a is coordinate-converted on a map stored in the navigation software 4b and displayed on the display 5 together with the traveling direction of the vehicle. Further, the FM antenna 2 and the FM antenna 2
The multiplex receiver 3 is for receiving a radio wave including road congestion information and the like, and the GPS receiver 4a displays the traffic congestion state of surrounding roads on the display 5 based on the information from the FM multiplex receiver 3. Is displayed.

On the other hand, the navigation body 4 travels on the navigation software 4b based on the current position and traveling direction obtained by the GPS receiver 4a and road data obtained from the navigation software 4b. A determination unit 4c for estimating or determining a road is provided. Here, the method of determining the traveling road by the determining means 4c will be briefly described. In this determining means 4c, when the own vehicle position and the traveling direction are calculated by the GPS receiver 4a, based on the coordinate data of the own vehicle position. Then, from among the plurality of maps stored in the navigation software 4b, first, a map (for example, equivalent to a scale 1/25000) including the own vehicle position is selected. After selecting the map information, the current position of the vehicle is converted into coordinates on the map, and the current position, the traveling direction, and the display 5 are displayed.

Next, all coordinates constituting the road on the selected map are read, and the distance from the own vehicle position and the direction of the road are calculated for each coordinate. In the determination means 4c, based on such a calculation result, the distance L from the own vehicle position is equal to or less than a predetermined distance (for example, 100 m), and the angle between the road direction and the traveling direction of the own vehicle is a predetermined value (for example, 30 °) or less and a coordinate point existing in front of the own vehicle is detected as a forward coordinate candidate point. When there are a plurality of such forward coordinate candidate points, a coordinate having the shortest distance from the host vehicle is selected, and this coordinate is set again as a forward coordinate candidate point.

Then, the determination means 4c determines that the road having the forward coordinate candidate points set as described above is the road on which the vehicle is currently traveling. Next, the main part of the present invention will be described. The navigation main body 4 is provided with a road gradient calculating unit 4d for calculating a road gradient, in addition to the determining unit 4c. As shown in the figure, the road gradient calculating means 4d includes a vehicle position correcting means 41, a passing point setting means (or a virtual point setting means) 42, and a calculating means 43.
It is configured with and.

Further, as shown in FIG. 1, the navigation main body 4 has mesh elevation data 4e as elevation information storage means, and the road gradient calculation means 4d
The road gradient is calculated using the altitude data (altitude information) from the mesh altitude data 4e. The mesh elevation data 4e is stored in the navigation body 4
May be provided outside.

Here, the mesh elevation data 4e is elevation data provided by the Geospatial Information Authority of Japan, as described in the background art, and is obtained in the form of a recording medium such as a CD ROM as in the case of the navigation software. Can be done. Although the mesh elevation data 4e does not include map information such as roads, the whole country is divided into meshes by small square areas in the mesh elevation data 4e, and the elevation at the center of each area is stored. I have. In this embodiment, mesh elevation data is used in which the entire country is divided into small squares each having a side length of about 10 m as one region.

Next, a method of calculating a road gradient using the mesh elevation data 4e will be described, while explaining the functions of the means 41 to 43. The own vehicle position correcting means 41 compares the own vehicle position information obtained by the GPS receiver 4a with the map information of the navigation software 4b, and when the own vehicle position is not located on the road of the map, The self-vehicle position is corrected so that the self-vehicle position coincides with the road.

That is, the position information obtained by the normal GPS receiver 4a includes an error of about 100 m at the maximum, and the position of the own vehicle obtained by the GPS receiver 4a does not always coincide with the road. Not exclusively. Therefore, the own-vehicle position correcting means 41 performs correction so that the own-vehicle traveling road set by the determination means 4c matches the own-vehicle position.

For example, in FIG. 2, the position of the vehicle is X (x,
y), the own-vehicle-position correcting means 41 drops a perpendicular to the traveling road determined by the above-described determining means 4c, and intersects Q ₀ (mx) between the perpendicular and the road.
₀ , my ₀ ) is set as the own vehicle position. In FIG. 2, the x coordinate indicates longitude, and the y coordinate indicates latitude.

An example of a method of calculating the corrected vehicle position Q ₀ (mx ₀ , my ₀ ) will be briefly described with reference to FIG. 2. First, an equation representing a straight line P ₀ P ₁ is set as Y = aX + b. By substituting P ₀ (x ₀ , y ₀ ) and P ₁ (x ₁ , y ₁ ), a and b are obtained. That is, a and b can be represented by the following equations. a = (y ₁ −y ₀ ) / (x ₁ −x ₀ ) b = y ₁ −a · x _{1 Using} the above a and b, mx ₀ and my ₀ can be expressed as follows, for example. it can.

Mx ₀ = x + a · (y−ax−b) / (1 + a ² ) my ₀ = y− (y−ax−b) / (1 + a ² ) At a predetermined distance L (for example, 10 m) based on the corrected vehicle position Q ₀ along the traveling direction of the vehicle.
₁ to Q ₅₎ is adapted to be set. Here, the predetermined distance L is a distance in a plan view, and when the road is inclined, L is different from the actual road.
In the navigation software 4b, road information is stored as a set of a plurality of coordinate points, and as shown in FIG. 2, a road is approximated by connecting adjacent coordinate points with a straight line. In this case, the distance between adjacent coordinate points varies depending on the road conditions, but is usually about 30 to 50 m, and the set interval L between the virtual points is preferably a smaller value.

Then, the arithmetic means 43 displays the mesh elevation data 4 on the map obtained by the navigation software 4b.
e, the corrected own vehicle position Q ₀ and each virtual point Q ₁ .
Region Q ₅ is present removed (the region indicated in Figure 2 Chumo over), the points Q ₀ to Q ₅ each corrected elevation data existing region is vehicle position Q ₀ and the virtual point Q ₁ to Q ₅ It is set as the altitude at.

Strictly speaking, this altitude data is the altitude of the center point of each area, and does not always match the altitude of each passing point. However, as described above, the mesh altitude data 4e used in this embodiment Since each area is a small area of 10 m square, a large error does not occur even if the elevation of the area where the passing point exists is used as the elevation of the passing point. Further, even if an error occurs, the error is filtered by averaging described later, and the error is absorbed.

Now, as described above, the elevation of each virtual point
, The corrected vehicle position Q₀Elevation and the elevation of each virtual point
From the difference, the corrected vehicle position Q₀And the gradient between each virtual point
Each is calculated, averaged, and the road gradient ahead is calculated.
Is calculated. Specifically, the corrected vehicle position
Place Q₀And virtual point Q₁~ Q_FiveThe elevation of each Z₀~ Z
_FiveThen, the corrected vehicle position Q₀From each virtual point Q₁~ Q_Five
Road slope α₁~ Α _FiveIs as follows.

Α ₁ = (Z ₁ −Z ₀ ) / L α ₂ = (Z ₂ −Z ₀ ) / 2L α ₃ = (Z ₃ −Z ₀ ) / 3L α ₄ = (Z ₄ −Z ₀ ) / 4L α ₅ = (Z ₅ −Z ₀ ) / 5L Then, the above equations are substituted into the following equations to obtain the average road gradient α
_AVE is calculated.

Α _AVE = (α ₁ + α ₂ + α ₃ + α ₄ + α ₅ ) / 5 Then, when the road gradient is calculated by the calculating means 43 in this way, the transmission speed change control or the like is performed using the road gradient. Traction control and the like are executed. It should be noted that specific examples of such transmission shift control include, for example, shift stage switching control and shift timing change in accordance with the road gradient. In addition to the above, the present invention may be applied to control of an automatic light distribution lamp, an automatic brake system, and the like.

Since the road gradient calculating apparatus according to one embodiment of the present invention is configured as described above, its operation will be described as follows. First, step S1 in FIG.
Then, the road on which the vehicle is currently traveling is determined by the determining means 4c. That is, when the vehicle position (latitude and longitude) is detected by the GPS receiver 4a, the determination unit 4c determines
Based on the coordinate data of the vehicle position, the navigation software 4b
Then, a map including the position of the own vehicle is selected from, and all coordinates constituting the road on the map are read, and the distance from the own vehicle position and the direction of the road (inclination on the map) are calculated for each coordinate.

The distance from the position of the own vehicle is equal to or less than a predetermined distance (for example, 100 m), the angle between the direction of the road and the traveling direction of the own vehicle is equal to or less than a predetermined value (for example, 30 °), and A coordinate point existing ahead is set as a forward coordinate candidate point.
When there are a plurality of such forward coordinate candidate points,
The coordinates with the shortest distance from the own vehicle are selected, and these coordinates are set as the forward coordinate candidate points again. Then, it is determined that the road having the forward coordinate candidate point set as described above is the road on which the vehicle is currently traveling. The method for determining or estimating the current traveling road is not limited to the above-described method, and the traveling road may be determined by another method.

Next, the process proceeds to step S2, in which the own vehicle position obtained by the GPS receiver 4a is corrected on the traveling road determined in step S1. In this case, specifically a perpendicular line is drawn from the vehicle position relative to the running road, and sets the intersection of the perpendicular line and the traveling road as the correction vehicle position Q _0. In step S3, the corrected vehicle position Q ₀ as a reference, a predetermined distance L forward along the traveling road
A plurality of virtual points Q _{1 to} Q ₅ are set for each, and each of the points Q ₀ to Q ₅ is set based on information from the mesh elevation data 4e.
₅ obtains the position altitude regions, sets the altitude of the altitude at each point Q ₀ to Q ₅ again.

After setting the altitude of each of the virtual points Q _{0 to} Q ₅ ,
Proceeding to step S4, the corrected own vehicle position Q ₀ and each virtual point Q ₁
The gradients α _{1 to} α ₅ with respect to Q ₅ are calculated, the respective gradients are averaged, and the averaged gradient is recognized as a road gradient ahead. Then, the process proceeds to step S5 to execute transmission control or the like using the road gradient information, and then returns.

As described above, according to the road gradient calculating apparatus according to the embodiment of the present invention, the vehicle position information from the vehicle position detecting means (GPS receiver) 4a and the altitude information storage means (mesh altitude data). Since the gradient of the road on which the vehicle is currently traveling is calculated using the altitude information from 4e, there is an advantage that the gradient of the road ahead can be easily and accurately known. Further, there is an advantage that the safety of the vehicle is greatly improved by performing the gear position control, the traction control and the like according to the road gradient.

The elevation of the mesh elevation data does not always match the elevation of each of the passing points Q _{0 to} Q _5. However, the use of mesh data in which one side is divided into a small area of about 10 m may cause an error. Can be reduced as much as possible. Further, even if an error is included in the altitude data, as described above, there is an advantage that the error can be almost eliminated by averaging the gradients and the road gradient can be accurately calculated.

Further, according to the present invention, since there is no need for an image pickup means such as a camera, there is an advantage that the calculation of the road gradient can be performed stably even at night or in bad weather.
Further, since no special sensor or the like is required and only the elevation information storage means (mesh elevation data) 4e needs to be added to the conventional navigation device, there is an advantage that cost and weight are hardly increased. Have.

Further, even if the position of the own vehicle is shifted from the road on the map due to an error in the position information obtained by the GPS receiver 4a, the own vehicle position is corrected by the own vehicle position correcting means 41. Since the correction is performed so as to match, there is an advantage that an accurate road gradient can be calculated. It should be noted that the road gradient calculating device of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the FM antenna 2 and the FM multiplex receiver 3 are not always necessary and may be omitted. Further, the method of determining the road on which the vehicle is currently traveling is not limited to the one in the present embodiment, and another method may be used. Furthermore, in the above description, an example in which the road gradient calculated in the present invention is applied to transmission control and traction control has been described, but how to use the calculated road gradient is not limited in any way.

[0039]

As described above in detail, according to the road gradient calculating apparatus of the present invention, a plurality of virtual points are set at a predetermined distance in front of the own vehicle position along the road on which the own vehicle runs. Then, based on the altitude information of the altitude information storage means, the altitude of the area where each virtual point exists is set as the altitude of each virtual point, and the gradient between the own vehicle position and each virtual point is calculated and calculated. Since the road gradient ahead of the own vehicle is calculated by averaging the obtained gradients, there is an advantage that the road gradient ahead of the currently traveling road can be easily and accurately known. Also, no special sensors are required,
Since it is only necessary to add the altitude information storage means to the conventional navigation device, there is an advantage that the cost and weight are hardly increased.

When the present apparatus is applied to a gear position control, a traction control, an automatic light distribution lamp, or the like,
There is an advantage that the traveling performance and safety of the vehicle are further improved. Further, according to the present invention, since an imaging means such as a camera is not required, there is an advantage that a road gradient can be stably calculated even at night or in bad weather.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram functionally showing a main configuration of a road gradient calculating device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a calculation method of a road gradient calculation device according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating an example of an operation of the road gradient calculating device according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 4 navigation body 4a own vehicle position detecting means (GPS receiver) 4b map information storing means (navigation software) 4c determining means 4d road gradient calculating means 4e altitude information storing means (mesh altitude data) 41 own vehicle position correcting means 42 passing point Setting means (or virtual point setting means) 43 calculating means

Claims (1)

[Claims] 1. a vehicle position detecting means for detecting a current position and a traveling direction of a vehicle; a map information storing means for storing data of a plurality of coordinate points constituting a road; Altitude information storage means for storing the altitude information of the area; and the position information from the vehicle position detecting means being coordinate-converted onto a map obtained from the map information storage means, and the current position of the vehicle on the map and A determination means for determining the traveling direction is provided, and a plurality of virtual points are set forward by a predetermined distance along the traveling road of the own vehicle starting from the own vehicle position detected by the own vehicle position detection means. Based on the altitude information stored in the altitude information storage means, the altitude of an area where each virtual point exists is set as the altitude of the virtual point, and the gradient between the vehicle position and the virtual point is respectively Calculate and flatten each gradient It turned into, characterized in that it includes a road gradient calculating means for calculating a road grade ahead of the the free-wheel in. Road slope calculator.