JPH0844996A - Navigation device for vehicle - Google Patents

Abstract

PURPOSE:To change a road map range which is displayed on a display screen according to a vehicle speed. CONSTITUTION:This vehicle navigation device has an azimuth sensor 1, a vehicle speed sensor 2, and a CPU 4, and after a recommended route from a starting point to a destination is calculated, a view position and a sight line direction for a bird's-eye view display are determined on the basis of the current position and speed of the vehicle. For example, the angle at which the road map is looked down from the view point is made invariably constant irrelevantly to the vehicle speed and the view point position is changed according to the vehicle speed. In concrete, the view point position is made higher and higher as the vehicle speed is faster and faster. In another way, the distance between the view point and the tip position of the line of sight is made invariably constant irrelevantly to the vehicle speed and the angle at which the map is looked down from the view point is varied according to the vehicle speed. In concrete, the look-down angle is made smaller and smaller as the vehicle speed is faster and faster. Through those processes, a road map which is wider as the vehicle speed is fast can be displayed on a display unit and a detailed road map of the peripehry of the current position as the vehicle speed is slow can be displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular navigation device in which a road map around a vehicle's current location is displayed on a display, and more particularly to a vehicular navigation device in which the scale of a road map displayed on the display can be changed. .

[0002]

2. Description of the Related Art There is known a vehicular navigation device which displays a road map around a current position of a traveling vehicle on a display. In this type of device, the display screen is rewritten every time the vehicle travels a predetermined distance so that the vehicle position is always displayed on the screen. Therefore, the higher the traveling speed of the vehicle, the more the number of times the screen is rewritten per unit time, and the screen is frequently switched when the vehicle travels at a high speed. In such a case, the driver cannot afford to fully check the various information displayed on the screen. Therefore, in the device disclosed in Japanese Patent Laid-Open No. 2-130412, the map scale displayed on the screen is always the same, and the road map information on the screen is changed according to the traveling speed of the vehicle so that the vehicle operates at high speed. When driving, by displaying only important road map information, for example, high-order road type information such as highways and major national roads, even if the vehicle is traveling at high speed, the information required by the driver can be displayed. I am able to understand immediately.

There is also known a vehicle navigation device in which the scale of the road map displayed on the display can be changed in several stages by a changeover switch or the like. However, since it is troublesome to operate the changeover switch every time the scale is changed, for example, Japanese Patent Laid-Open No. 2-61690.
The publication discloses a vehicle navigation device adopting a so-called superimpose system, which simultaneously displays a large-scale road map and a small-scale road map on a screen. In the device described in this publication, the area around the current location of the vehicle is displayed at a large scale, and the area far away from the current location is displayed at a small scale. However, with this device, a large-scale road map and a small-scale road map are displayed simultaneously on the same screen, so it is difficult to understand how the road networks are connected, and the connection status of the road networks near the boundaries of each area can be grasped. It's not easy to do, and the distance intervals are hard to understand.

In order to solve such a problem, it is possible to display a road map in a bird's eye view, for example. This display is displayed on the display as if the road map is looked down diagonally from the sky, and has been widely used in flight simulators and the like. FIG. 10 is a diagram for explaining the outline of the bird's-eye view display. Figure 10 shows a road map X
An example in which the viewpoint E is set on the Y axis and the Z axis orthogonal to the XY plane is shown. The illustrated rectangle abcd indicates the display range of the display, and the road map range that can be seen from the illustrated viewpoint E through the rectangle abcd is indicated by the trapezoid ABCD. As shown in the figure, from the viewpoint position, a rectangle abcd
You can see the road map data of a much wider range than the range of.

A display method for displaying an image on the display as if the trapezoidal area ABCD shown in the drawing is viewed from the illustrated viewpoint position is generally called a bird's-eye view display method. This bird's-eye view display method has a feature that the side closer to the viewpoint is displayed in a more enlarged manner. For example,
The position on the trapezoid ABCD corresponding to the center position f of the rectangle abcd indicating the display display range is indicated by F, and this point F is closer to the side AB than the side CD. That is, the area from side AB to point F is displayed in the lower half of the display. The side AB is shorter than the side CD, and the side AB side is enlarged and displayed accordingly.

FIG. 11A shows an example in which a road map around the recommended route from the current position of the vehicle to the destination is displayed on the display using the bird's-eye view display system. In this figure, the viewpoint is placed above the direction opposite to the destination based on the present location, and the direction of the destination is looked down from there. When the viewpoint is placed at such a position, an image in which the scale factor of the map continuously increases as the destination approaches the current position as shown in the figure is displayed. That is, the area around the current location is enlarged and displayed, and the recommended route is displayed up to the destination. FIG. 11B is an example of a conventional map display screen when the vehicle mark is displayed at a screen position almost equal to that of FIG.
Compared to FIG. 10 (b), in FIG. 10 (a), the vicinity of the current location is enlarged and displayed, and the recommended route indicated by a thick line is also displayed longer than in FIG. 10 (b).

[0007]

However, when a road map is displayed by the bird's-eye view display method, the map range displayed on the display changes depending on where the viewpoint is set, and the driver sees it depending on how the viewpoint is placed. The desired range cannot be displayed satisfactorily. Generally, when driving at high speed, the driver often wants to see a road map farther than the map around the current location, and vice versa.
If you are driving slowly, you often want to see a detailed map of your current location. However, the conventional vehicle navigation device does not perform a process of changing the map scale on the screen according to the vehicle traveling speed, and when changing the scale, the driver operates the changeover switch etc. by himself / herself. There must be.

An object of the present invention is to provide a vehicle navigation device capable of changing the map scale when a road map is displayed in a bird's eye view according to the traveling speed of the vehicle.

[0009]

The present invention will be described with reference to FIG. 1 showing an embodiment. In the present invention, a road map storage means 3 for storing road map data relating to a road map, and a current position of a vehicle are detected. Vehicle position detecting means 1, 2, 10
And, a bird's-eye view creating means for creating a bird's-eye view that looks down in a predetermined direction of the road map from this viewpoint by setting a viewpoint in the sky opposite to the destination based on the current location on the road map, and displaying the created bird's-eye view on the display The present invention is applied to a vehicular navigation device having a display control means for controlling the vehicle speed, and includes a vehicle speed detection means 2 for detecting the traveling speed of the vehicle. The position of the viewpoint and the viewpoint according to the vehicle speed detected by the vehicle speed detection means The above object is achieved by configuring the bird's-eye view creating means so as to change the direction in which the bird's-eye view looks down. According to a second aspect of the present invention, in the vehicle navigation device according to the first aspect, the current position of the vehicle is at the same position on the display screen of the display regardless of the traveling speed of the vehicle detected by the vehicle speed detecting means 2. As is displayed, a bird's-eye view creating means for changing the position of the viewpoint and the direction of looking down from the viewpoint is provided. According to a third aspect of the present invention, in the vehicular navigation device according to the first aspect, the higher the traveling speed of the vehicle detected by the vehicle speed detection means 2, the further the viewpoint is from the road map, and the angle from which the viewpoint is looked down is set. The bird's-eye view creating means is configured so as to be constant regardless of the traveling speed. According to a fourth aspect of the present invention, in the vehicular navigation device according to the first aspect, the higher the traveling speed of the vehicle detected by the vehicle speed detection means 2, the closer the viewpoint is to the road map, and the current position on the road map. The bird's-eye view creating means is configured so that the distance between the point of view and the viewpoint is constant regardless of the traveling speed.

[0010]

According to the first aspect of the invention, the bird's-eye view creating means changes the direction to look down from the viewpoint according to the traveling speed of the vehicle detected by the vehicle speed detecting means 2. The bird's-eye view creating means of the invention according to claim 2 changes the position of the viewpoint and the direction looking down from the viewpoint so that the current position of the vehicle is always displayed at the same position on the display screen of the display. The bird's-eye view creating means according to the third aspect of the present invention keeps the angle overlooking from the viewpoint irrespective of the traveling speed of the vehicle, and moves the viewpoint away from the road map as the traveling speed of the vehicle increases.
The bird's eye view creating means of the invention according to claim 4 keeps the distance between the current position on the road map and the viewpoint constant regardless of the traveling speed of the vehicle, and brings the viewpoint closer to the road map as the traveling speed of the vehicle increases. .

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0012]

1 is a block diagram of an embodiment of a vehicle navigation device according to the present invention. In FIG. 1, reference numeral 1 denotes an azimuth sensor that detects the traveling azimuth of the vehicle. Reference numeral 2 denotes a vehicle speed sensor that outputs a predetermined number of pulse signals according to the vehicle traveling speed, and is attached to, for example, a vehicle transmission. Reference numeral 3 is a map storage memory that stores road map data including intersection network data, and stores position information of nodes indicating intersections and curve points, route lengths of roads (links) connecting nodes and character information such as place names. Remember.

Reference numeral 4 denotes a CPU for performing the processing shown in FIG.
Reference numeral 5 denotes an R that stores a control program executed by the CPU 4
OM and 6 are RAMs for storing the calculation results by the CPU 4. A V-RAM 7 stores the bird's-eye view display data created by the CPU 4, and pictographic information is displayed on the display 8 according to the stored contents of the V-RAM 7. 9 is an operation board for inputting the present location or destination, 1
Reference numeral 0 is a GPS receiver that receives GPS signals from GPS satellites. Reference numeral 11 denotes an interface circuit, which includes a direction sensor 1, a vehicle speed sensor 2, a map storage memory 3, a CPU 4, and R.
Signals are exchanged among the OM 5, the RAM 6, the V-RAM 7, the display 8, the operation board 9 and the GPS receiver 10.

In the vehicle navigation system configured as shown in FIG. 1, the ignition key (not shown) is AC.
When operated by either C, IGN, or START, C
PU4 starts the process of the flowchart of FIG. The operation of this embodiment will be described below with reference to the flowchart of FIG. In step S1 of FIG. 2, the destination input by the operation board 9 is read. In step S2, a recommended route is calculated by performing a route search from a starting point to a destination using a known Dijkstra method (see Japanese Patent Laid-Open No. 62-86499). The departure point may be input from the operation board 9 as in step S1, or the GPS receiver 1
The origin may be specified by receiving a GPS signal by 0.

In step S3, the number of pulses per unit time or the pulse period output from the vehicle speed sensor 2 is measured to detect the traveling speed of the vehicle (hereinafter referred to as vehicle speed), and the number of pulses is measured to measure the vehicle speed. Detects the mileage of. Next, the traveling locus of the vehicle is calculated based on the detected vehicle traveling distance and the traveling azimuth of the vehicle detected by the azimuth sensor 1, and map matching is performed with the road map data stored in the map storage memory 3. Identify the current location of the vehicle. When the reception state of the GPS receiver 10 is good, the vehicle speed and the current position are calculated based on the GPS signal received by the GPS receiver 10, and the vehicle speed and the current position are specified by referring to the calculation result.

In step S4, the viewpoint E and the line-of-sight direction EF at the time of displaying the bird's-eye view are determined by the processing of FIG. 3 described later based on the vehicle speed and the current position detected in step S3. In step S5, the map range displayed on the display 8 is calculated. That is, it is calculated to which range on the road map the trapezoid ABCD of FIG. 10 is set. In step S6, the road map data within the range calculated in step S5 is read from the map storage memory 3. In step S7, the road map data read in step S6 is converted into bird's-eye view display data. That is, the trapezoidal ABC of FIG.
The road map data within the range of D is displayed on the screen display area a shown in the figure.
Convert to image data for display in bcd.

The equation for performing this conversion is represented by equation (1), as is generally known. In equation (1), the coordinates of the viewpoint position are (Vx, Vy, 0), the coordinates on the map are (Mx, My, 0), and the coordinates on the display screen are (Sx, Sy). In addition, (Ex, Ey, E
z) is an intermediate value for obtaining (Sx, Sy).

[Equation 1] When the image data is created in step S7, the recommended route obtained in step S2 is colored in a different color so that it can be distinguished from normal road map data, and the position corresponding to the current position of the vehicle obtained in step S3 is set. Combine vehicle mark data.

In step S8, the image data created in step S7 is transferred to the V-RAM 7. This allows
The road map data converted into the bird's-eye view display data is displayed on the display 8. In step S9, it is determined whether the vehicle has moved a predetermined distance or more. This determination is based on the output of the vehicle speed sensor 2 or G
The PS signal is received and judged. If the determination is affirmative, the process returns to step S3, the viewpoint E and the line-of-sight direction EF are calculated again,
The screen is rewritten based on the result. On the other hand, if the determination in step S9 is negative, the process stays in step S9.

FIG. 3 is a flow chart showing the details of the processing in step S4 of FIG. 2, and FIG. 4 shows an example of the viewpoint position and line-of-sight direction set by this flow chart. FIG.
Then, the viewpoint position is indicated by E1 or E2, and the tip position F of the line of sight is set near the current position on the road map. In the first embodiment, the angle θ looking down from the viewpoint is always constant as shown in FIG. 4, and the line-of-sight direction is the line-of-sight direction EF.
An angle φ between the direction AA ′ and the x-axis, which is the projection of γ onto the xy plane.
Determined by Further, in the first embodiment, the viewing angle when viewing the road map from the viewpoint E is always constant. That is, as shown in FIG. 5, since the distance L between the viewpoint position E and the apparent display screen position abcd is always constant and the area of the display screen is common, FIG.
As shown in (b), the vertical viewing angle 2γ and the horizontal viewing angle 2β are always constant regardless of the viewpoint position.

In step S101 of FIG. 3, the vicinity of the current position of the vehicle specified in step S2 of FIG. 2 is set as the tip position F of the line of sight. In step S102, the line-of-sight direction angle φ is determined. The line-of-sight direction is obtained, for example, by any one of the following, but may be obtained by a method other than. The traveling direction of the vehicle detected by the azimuth sensor 1 is set as the line-of-sight direction. The viewing direction is the direction in which the recommended route is displayed for the longest time. The direction of the destination is the line-of-sight direction based on the current location. In step S103, the size of the line-of-sight direction vector EF (hereinafter referred to as the line-of-sight) is calculated based on the equation (2).

[Equation 2] | EF | = k ₁ + k ₂ × vehicle speed (2) However, when k ₁ and k ₂ are calculated by a positive constant value (2), the shorter the vehicle speed, the shorter the line of sight. The longer the vehicle speed, the longer the line of sight is set.

In step S4, the viewpoint position E is obtained based on the line-of-sight tip position F, the angle θ looking down from the viewpoint E, the line-of-sight length | EF |, and the line-of-sight direction angle φ. For example, FIG. 4 shows a case where the viewpoint E ₁ has a low vehicle speed and a viewpoint E ₂ has a high vehicle speed. Further, the map ranges displayed on the display when the viewpoint positions are E ₁ and E ₂ are indicated by trapezoidal areas A ₁ B ₁ C ₁ D ₁ and A ₂ B ₂ C ₂ D ₂ , respectively.

FIG. 6 is a diagram in which the AA 'direction in FIG. 4 is the horizontal axis and the vertical axis is the z axis. As shown in FIG. 6, the viewpoint E
The map range when placed at ₁ is G ₁ H ₁ , the map range when the viewpoint is at E ₂ is G ₂ H ₂ , and the viewpoint E ₂ with a longer line of sight has a wider range. It can be seen that the road map of can be displayed.

As described above, in the first embodiment, the angle θ looking down from the viewpoint E is always constant, and the length of the line of sight is changed in accordance with the vehicle speed. The higher the vehicle speed, the longer the line of sight. ing. Accordingly, the higher the vehicle speed, the wider the road map can be displayed, and the lower the vehicle speed, the more detailed the road map around the current position can be displayed. Therefore, the road map can be displayed in accordance with the driver's intention.

In step S103 of FIG. 3, the length of the line of sight is continuously changed according to the vehicle speed, but the length of the line of sight may be changed stepwise according to the vehicle speed. For example, the line-of-sight length | EF | may be set in four stages as follows. When the vehicle speed is less than 20 km / h, | EF | = EF1 20 km / h to 40 km / h, | EF | = EF2 40 km / h to 70 km / h, | EF | = EF3 70 km / h or more, | EF | = EF4 However, EF1 <EF2 <EF3 <EF4

In the first embodiment, when the vehicle speed is very high, the road network information displayed on the display 8 may be too large, and the screen may be difficult to see. Therefore, in such a case, only important information, for example, high-order road types such as highways, may be displayed.

Second Embodiment In the second embodiment, the angle of looking down the road map from the viewpoint is changed according to the vehicle speed. The second embodiment is shown in FIG.
Since it is common to the first embodiment except step S4 of
The second embodiment will be described below with reference to the flowchart of FIG. 7 showing the details of step S4 of FIG. In the second embodiment, as shown in FIG. 8, the viewpoint E and the tip position F of the line of sight are
The distance between and is always constant, and the line-of-sight direction EF is changed according to the vehicle speed. In the second embodiment, as in the first embodiment, the vicinity of the current position on the road map is set as the tip position F of the line of sight.

In steps S201 and S202 of FIG.
Similar to steps S101 and S102 of FIG. 3, after detecting the current position of the vehicle, the line-of-sight direction angle φ is set. Next, in step S203, the angle θ overlooking the road map is set based on the equation (3).

[Equation 3] θ = k ₃ −k ₄ × vehicle speed (3) However, if k ₃ and k ₄ are calculated according to a positive constant (3), the angle θ overlooking the road map increases as the vehicle speed increases. The value becomes smaller.

In step S204, the line-of-sight tip position F,
The viewpoint position E is set based on the angle θ to look down, the size of the line-of-sight vector EF, and the line-of-sight direction angle φ. In FIG. 8, when the vehicle speed is high, the viewpoint position is E ₃ , the angle to look down is θ ₃ , and the road map range displayed on the display 8 is A _3.
It is set to B ₃ C ₃ D _3. On the other hand, when the vehicle speed is low, the viewpoint position is E ₄ , the looking down angle is θ ₄ , and the road map range displayed on the display 8 is A ₄ B ₄ C ₄ D ₄ .

FIG. 9 shows a diagram in which the horizontal axis is the AA 'direction and the vertical axis is the z axis in FIG. As shown in FIG. 9, the viewpoint E
The map range when placed at ₃ is indicated by G ₃ H ₃ , and the map range when the start point is placed at E ₄ is indicated by G ₄ H ₄ . As shown in FIGS. 8 and 9, in the second embodiment, the higher the vehicle speed, the smaller the angle φ to look down, so the road map range displayed on the display 8 becomes wider.

As described above, in the second embodiment, the distance between the viewpoint position and the tip position of the line of sight is always fixed, and the angle overlooking the road map is changed according to the vehicle speed. Specifically, the higher the vehicle speed, the smaller the angle of looking down, and the lower the vehicle speed, the greater the angle of looking down. As a result, a wide map can be displayed when the vehicle speed is high, and a detailed map around the current position can be displayed when the vehicle speed is low. Further, in the second embodiment, the distance between the viewpoint position and the current position on the road map, which is the tip position of the line of sight, is always constant,
Even if the display screen is switched according to the vehicle speed, the scale around the current location can be made substantially constant, and an easy-to-see screen can be provided.

In each of the above embodiments, the device having the function of calculating the recommended route from the starting point to the destination and guiding the vehicle to the destination has been described, but the navigation device does not have the function of calculating the recommended route. The present invention can also be applied to. In the above embodiment, when the screen display on the display is switched according to the vehicle speed, how the viewpoint position and the line-of-sight direction are set may be displayed on the display.

In the embodiment configured as described above, the map storage memory 3 serves as the road map storage means, and the direction sensor 1,
The vehicle speed sensor 2 and the GPS receiver 10 correspond to vehicle position detecting means, step S4 of FIG. 2 corresponds to bird's-eye view creating means, and step S7 of FIG. 2 corresponds to display control means.

[0033]

As described in detail above, according to the present invention, the position of the viewpoint and the line-of-sight direction in displaying the bird's-eye view are changed according to the traveling speed of the vehicle, so that the driver's intention is met. The road map can be displayed and it is not necessary to switch the scale during driving. According to the second aspect of the present invention, the current position of the vehicle is always displayed at the same position on the display screen, so that the current position is not lost even if the scale of the road map is switched. According to the invention of claim 3, the angle overlooking from the viewpoint is always constant,
Since the viewpoint is moved away from the road map as the vehicle traveling speed is higher, a wider range of road maps can be displayed as the vehicle traveling speed is higher. According to the invention of claim 4, the distance between the current position on the road map and the viewpoint is always constant, and the viewpoint is closer to the road map as the vehicle traveling speed is higher. Therefore, the wider the vehicle traveling speed is, the wider the range is. You can display the road map of.

[Brief description of drawings]

FIG. 1 is a first vehicle navigation device according to the present invention.
3 is a block diagram of the embodiment of FIG.

FIG. 2 is a flowchart showing the processing of the CPU.

FIG. 3 is a flowchart showing details of the process of step S4 of FIG. 2 in the first embodiment.

FIG. 4 is a diagram showing movement in a viewpoint and a line-of-sight direction of the first embodiment.

FIG. 5 is a diagram showing a relationship between a viewpoint position and a display screen position.

FIG. 6 is a diagram in which the horizontal axis is the AA ′ direction and the vertical axis is the z axis after coordinate conversion of FIG. 4;

FIG. 7 is a flowchart showing details of the process of step S4 of FIG. 2 in the second embodiment.

FIG. 8 is a diagram showing movement in a viewpoint and a line-of-sight direction of the second embodiment.

9 is a diagram in which the horizontal axis is the AA ′ direction and the vertical axis is the z axis after coordinate conversion of FIG. 8;

FIG. 10 is a diagram illustrating a bird's-eye view display method.

FIG. 11 (a) is a bird's eye view of the area around the recommended route,
FIG. 6B is a diagram showing the area around the recommended route in a normal map display.

[Explanation of symbols]

 1 Vehicle speed sensor 2 Direction sensor 3 GPS receiver 4 Acceleration sensor 5 CPU 6 ROM 7 RAM 8 Display 9 Operation board 10 GPS receiver

Claims (4)

[Claims] 1. A road map storage means for storing road map data relating to a road map, a vehicle position detection means for detecting a current location of a vehicle, and a sky in a direction opposite to the destination based on the current location on the road map. A vehicle navigation device comprising a bird's-eye view creating means for creating a bird's-eye view looking down a predetermined direction of the road map from this viewpoint, and a display control means for displaying the created bird's-eye view on a display, The bird's-eye view creating means includes a vehicle speed detecting means for detecting a traveling speed of the vehicle, and the bird's-eye view creating means changes the position of the viewpoint and the direction looking down from the viewpoint according to the traveling speed of the vehicle detected by the vehicle speed detecting means. A characteristic vehicle navigation device. 2. The vehicle navigation apparatus according to claim 1, wherein the bird's-eye view creating unit displays the current position of the vehicle on the display screen of the display regardless of the traveling speed of the vehicle detected by the vehicle speed detecting unit. A vehicular navigation device, characterized in that the position of the viewpoint and the direction looking down from the viewpoint are changed so that they are displayed at the same position. 3. The vehicle navigation device according to claim 1, wherein the bird's-eye view creating unit moves the viewpoint away from the road map as the traveling speed of the vehicle detected by the vehicle speed detecting unit increases. A vehicular navigation device characterized in that an angle looked down from a viewpoint is made constant regardless of the traveling speed. 4. The vehicular navigation device according to claim 1, wherein the bird's-eye view creating unit brings the viewpoint closer to the road map as the traveling speed of the vehicle detected by the vehicle speed detecting unit increases, and A vehicle navigation device characterized in that the distance between the current position on the road map and the viewpoint is constant regardless of the traveling speed.