JP3360425B2 - Vehicle navigation system - Google Patents

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 for displaying a road map around the current location of a vehicle on a display, and more particularly to a vehicular navigation device for changing the scale of a road map displayed on a display. .

[0002]

2. Description of the Related Art There is known a vehicular navigation apparatus for displaying a road map around a current position of a running 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. For this reason, the screen rewriting frequency per unit time increases as the traveling speed of the vehicle increases, and the screen changes frequently when the vehicle travels at a high speed. In such a case, the driver cannot afford to sufficiently check various information displayed on the screen. Therefore, in the device disclosed in Japanese Patent Application Laid-Open No. 2-130412, the map scale displayed on the screen is always made common, the road map information in the screen is changed according to the traveling speed of the vehicle, and the vehicle is operated at high speed. When traveling, by displaying only important road map information, for example, high-level road type information such as expressways and major national roads, even if the vehicle travels at high speed, the information required by the driver can be obtained. It is possible to grasp immediately.

There is also known a vehicular navigation device in which the scale of a road map displayed on a display can be changed in several stages by a changeover switch or the like. However, it is troublesome to operate the changeover switch every time the scale is changed.
Japanese Patent Application Publication No. JP-A-2003-115122 discloses a vehicle navigation apparatus that employs a so-called superimpose method in which a large-scale road map and a small-scale road map are simultaneously displayed on a screen. In the device described in this publication, a large scale is displayed around the current location of the vehicle, and a small scale is displayed at a distance from the current location. However, with this device, a large-scale road map and a small-scale road map are simultaneously displayed on the same screen, making it difficult to understand how the road networks are connected. It is not easy to do, and it is hard to understand the distance interval.

In order to solve such a problem, for example, a road map may be displayed in a bird's eye view. This display is such that a road map is displayed on a display as viewed obliquely from above, and has been widely used in flight simulators and the like. FIG. 10 is a diagram illustrating an outline of the bird's-eye view display. FIG. 10 shows a road map X
An example is shown in which the viewpoint E is set on the Z axis orthogonal to the XY plane as the Y plane. 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 a trapezoid ABCD. As shown in the figure, a rectangular abcd
You can see a much wider range of road map data than the range.

[0005] A display system for displaying an image on a display as if looking at the illustrated trapezoidal area ABCD from the illustrated viewpoint position is generally called a bird's-eye view display system. The bird's-eye view display method has a feature that the side closer to the viewpoint is displayed in a larger scale. 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 is enlarged and displayed by that much.

FIG. 11A shows an example in which a road map around a recommended route from the current position of a vehicle to a destination is displayed on a display using a bird's eye view display method. In this figure, a viewpoint is set in the sky in the direction opposite to the destination based on the current position, and the direction of the destination is viewed from there. When the viewpoint is placed at such a position, as shown in the figure, an image in which the scale of the map continuously increases as approaching the current location from the destination is displayed. In other words, the area around the current location is enlarged and displayed, and the recommended route is displayed near the destination. FIG. 11B is an example of a conventional map display screen when a vehicle mark is displayed at a screen position substantially equal to that of FIG. 10A.
In FIG. 10A, the vicinity of the current position is displayed in an enlarged manner as compared with FIG. 10B, and the recommended route indicated by a thick line is displayed longer than in FIG. 10B.

[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. The desired range cannot be displayed satisfactorily. Generally, when driving at high speeds, drivers often want to see a road map that is more distant than a map around their current location,
If you are driving slowly, you often want to see a detailed map around 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 himself operates a changeover switch or the like. There must be.

[0008] It is an object of the present invention to provide a vehicular navigation device that can change the scale of a map when a road map is displayed in a bird's-eye view according to the vehicle traveling speed.

[0009]

The present invention will be described with reference to FIG. 1 showing an embodiment.
A road map storage means for storing road map data relating to the road map, and a bird's eye view which looks down at a predetermined direction of the road map from this viewpoint with a viewpoint placed above the direction opposite to the destination based on the current position on the road map. A vehicular navigation apparatus including a bird's-eye view creating means for performing the navigation and a display control means for displaying the created bird's-eye view on a display, comprising a vehicle speed detecting means 2 for detecting a traveling speed of the vehicle,
The bird's-eye view creating means is configured to move the viewpoint away from the road map as the traveling speed of the vehicle detected by the vehicle speed detecting means 2 increases, and to keep the angle of looking down from the viewpoint constant regardless of the traveling speed. According to a second aspect of the present invention, there is provided a road map storage means for storing road map data relating to a road map, a view point placed in the sky in a direction opposite to a destination on the basis of a current position on the road map, and a road map stored from this viewpoint. Is applied to a vehicular navigation apparatus including a bird's-eye view creating means for creating a bird's-eye view looking down on a predetermined direction and a display control means for displaying the created bird's-eye view on a display. The bird's-eye view is prepared so that the viewpoint is closer to the road map as the traveling speed of the vehicle detected by the vehicle speed detecting means 2 is higher, and the distance between the current position on the road map and the viewpoint is constant regardless of the traveling speed. It constitutes the means.

[0010]

According to the first aspect of the present invention, the bird's-eye view creating means always keeps the angle looking down from the viewpoint constant irrespective of the running speed of the vehicle, and shifts the viewpoint to the road as the running speed of the vehicle detected by the vehicle speed detecting means 2 increases. Keep away from the map. The bird's-eye view creating means according to the second aspect of the present invention always keeps the distance between the current position on the road map and the viewpoint irrespective of the traveling speed of the vehicle, and moves the viewpoint closer to the road map as the traveling speed of the vehicle increases. .

In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0012]

FIG. 1 is a block diagram showing an embodiment of a vehicle navigation system according to the present invention. In FIG. 1, reference numeral 1 denotes a direction sensor for detecting the direction of travel of a 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 transmission of the vehicle. Reference numeral 3 denotes a map storage memory that stores road map data including intersection network data, and stores position information of nodes indicating intersections and curve points, character information such as a path length of a road (link) connecting the nodes and a place name, and the like. Remember.

Reference numeral 4 denotes a CPU for performing the processing of FIG.
5 is an R for storing a control program executed by the CPU 4 and the like.
OM and 6 are RAMs for storing the calculation results of the CPU 4. Reference numeral 7 denotes a V-RAM for storing bird's-eye view display data created by the CPU 4, and pictographic information is displayed on the display 8 in accordance with the contents stored in the V-RAM 7. 9 is an operation board for inputting a current location or a destination, 1
Reference numeral 0 denotes a GPS receiver that receives a GPS signal from a GPS satellite. 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,
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 vehicular navigation apparatus configured as shown in FIG. 1, an ignition key (not shown) is
When operated by C, IGN, or START, C
The PU 4 starts the processing of the flowchart of FIG. Hereinafter, the operation of the present embodiment will be described based on 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 the departure point to the destination using a known Dijkstra method (see Japanese Patent Application Laid-Open No. 62-86499) or the like. Note that the departure place may be input from the operation board 9 as in step S1, or the GPS receiver 1
The departure point may be specified by receiving a GPS signal with 0.

In step S3, the number of pulses or the pulse period per unit time output from the vehicle speed sensor 2 is measured to detect the running speed of the vehicle (hereinafter referred to as the vehicle speed), and the number of pulses is measured to measure the number of pulses. The running distance of the vehicle is detected. Next, a traveling locus of the vehicle is calculated based on the detected traveling distance of the vehicle and the traveling direction of the vehicle detected by the direction sensor 1, and the 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 comparing the calculation results.

In step S4, based on the vehicle speed and the current position detected in step S3, the viewpoint E and the line-of-sight direction EF for displaying the bird's-eye view are determined by the processing of FIG. In step S5, a map range to be displayed on the display 8 is calculated. That is, it calculates 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 trapezoid ABC of FIG.
The road map data within the range D is displayed on the screen display area a shown in FIG.
The image data is converted into image data to be displayed in the bcd.

The equation for performing this conversion is expressed 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). Also, (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 set to a different color so as to be distinguishable from ordinary road map data, and the position corresponding to the current position of the vehicle obtained in step S3 is Combines 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 to 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 made based on the output of the vehicle speed sensor 2 or G
Judge by receiving the PS signal. If the determination is affirmative, the process returns to step S3, where 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 flowchart showing details of the processing in step S4 in FIG. 2, and FIG. 4 shows an example of the viewpoint position and the line-of-sight direction set by this flowchart. FIG.
In this example, 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.
Is the angle φ between the direction AA ′ that is projected on the xy plane and the x axis.
Is determined by 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, 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 also common.
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. In step S102, the line-of-sight direction angle φ is determined. The line-of-sight direction is obtained by, for example, any of the following, but may be obtained by a method other than the following. The traveling direction of the vehicle detected by the direction sensor 1 is defined as the line of sight. The direction in which the recommended route is displayed the longest is defined as the viewing direction. The direction of the destination is set as the line of sight based on the current location. In step S103, the magnitude of the line-of-sight direction vector EF (hereinafter, referred to as the line-of-sight length) is determined based on the equation (2).

| EF | = k ₁ + k ₂ × vehicle speed (2) Here, k ₁ and k ₂ are positive constant values. When calculated by equation (2), the line of sight becomes shorter as the vehicle speed becomes lower. The length of the line of sight is set longer as the vehicle speed increases.

In step S4, the viewpoint position E is determined 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. In Figure 4, for example, shows a case viewpoint E ₁ is the vehicle speed is low, a case viewpoint E ₂ is the vehicle speed is high. The map ranges displayed on the display when the viewpoint positions are at E ₁ and E ₂ are indicated by trapezoidal regions 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 direction of AA ′ in FIG. 4 is set as the horizontal axis and the vertical axis is set as the z-axis. As shown in FIG.
The map range when placed on ₁ is indicated by G ₁ H ₁ , and the map range when the viewpoint is set on E ₂ is indicated by G ₂ H ₂ , and the viewpoint E ₂ with a longer line of sight has a wider range. It can be seen that a road map 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. ing. As a result, a wider road map can be displayed as the vehicle speed is higher, and a detailed road map around the current location can be displayed as the vehicle speed is lower, so that a road map display according to the driver's intention can be performed.

In step S103 of FIG. 3, the length of the line of sight is continuously changed according to the vehicle speed. However, 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 determined in four steps as follows. When the vehicle speed is less than 20 km / h, | EF | = EF1 When 20 km / h to 40 km / h, | EF | = EF2 When 40 km / h to 70 km / h, | EF | = EF3 When 70 km / h or more, | EF | = EF4 where EF1 <EF2 <EF3 <EF4

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

Second Embodiment In a second embodiment, an angle at which a road map is looked down from a viewpoint is changed according to the vehicle speed. FIG. 2 shows a second embodiment.
Except that step S4 is common to the first embodiment.
Hereinafter, the second embodiment will be described with reference to a flowchart of FIG. 7 showing details of step S4 of FIG. In the second embodiment, as shown in FIG.
Is always constant, and the line-of-sight direction EF is changed according to the vehicle speed. In the second embodiment, similarly to the first embodiment, the vicinity of the current position on the road map is set as the front end position F of the line of sight.

In steps S201 and S202 in FIG.
Similar to steps S101 and S102 in FIG. 3, after detecting the current position of the vehicle, the gaze direction angle φ is set. Next, in step S203, an angle θ at which the road map is looked down is set based on equation (3).

Equation 3] θ = k ₃ -k ₄ × speed (3) where, k ₃ and k ₄ are when calculated in accordance with positive constant (3), overlooking the road map as the vehicle speed increases the angle theta of The value decreases.

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

FIG. 9 is a diagram in which the direction of AA ′ in FIG. 8 is set as the horizontal axis and the vertical axis is set as the z-axis. As shown in FIG.
The map range when set at ₃ is indicated by G ₃ H ₃ , and the map range when the start point is set 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 on, so that 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 end of the line of sight is always kept constant, and the angle at which the road map is looked down is changed according to the vehicle speed. Specifically, the lower the vehicle speed is, the smaller the angle to look down is, and the lower the vehicle speed is, the larger the angle is to look down. Thus, when the vehicle speed is high, a wide-range map can be displayed, and when the vehicle speed is low, a detailed map around the current location can be displayed. In the second embodiment, the distance between the viewpoint position and the current position on the road map, which is the front end position of the line of sight, is always constant.
Even when the display on the display screen is switched according to the vehicle speed, the scale near the current location can be made substantially constant, so that an easy-to-view screen can be provided.

In each of the above embodiments, a device having a function of calculating a recommended route from a departure point to a destination and guiding a vehicle to a destination has been described. However, a navigation device not having a function of calculating a recommended route is provided. The present invention can be applied also to this. 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 are set may be displayed on the display.

In the embodiment thus constructed, the map storage memory 3 corresponds to the road map storage means, step S4 in FIG. 2 corresponds to the bird's eye view creation means, and step S7 in FIG. 2 corresponds to the display control means. I do.

[0033]

As described in detail above, according to the present invention, the angle of the bird's-eye view display from the viewpoint is always kept constant, and the higher the vehicle traveling speed, the farther the viewpoint is from the road map. The higher the traveling speed, the wider the road map can be displayed. According to the present invention, the distance between the current position and the viewpoint on the road map when displaying the bird's-eye view is always constant, and the viewpoint is closer to the road map as the vehicle traveling speed is higher. Road map can be displayed.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a vehicle navigation device according to the present invention.
FIG.

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

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

FIG. 4 is a diagram illustrating movement of a viewpoint and a line of sight in 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 obtained by performing coordinate transformation on FIG. 4 and setting the horizontal axis to the AA ′ direction and the vertical axis to the z axis.

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

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

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

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

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

[Explanation of symbols]

 Reference Signs List 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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G08G 1/0969 G01C 21/00-21/36 G09B 29/00-29/00

Claims (2)

(57) [Claims] 1. A road map storage means for storing road map data relating to a road map; a viewpoint placed in a sky above a direction opposite to a destination based on a current position on the road map; A bird's-eye view creating means for creating a bird's-eye view looking down, and a display control means for displaying the created bird's-eye view on a display, comprising a vehicle speed detecting means for detecting a traveling speed of the vehicle, The bird's-eye view creating means moves the viewpoint away from the road map as the traveling speed of the vehicle detected by the vehicle speed detecting means increases, and makes an angle of looking down from the viewpoint constant regardless of the traveling speed. Vehicle navigation device. 2. Road map storage means for storing road map data relating to a road map; and a viewpoint placed in the sky in a direction opposite to a destination based on a current position on the road map, and a predetermined direction of the road map is determined from the viewpoint. A bird's-eye view creating means for creating a bird's-eye view looking down, and a display control means for displaying the created bird's-eye view on a display, comprising a vehicle speed detecting means for detecting a traveling speed of the vehicle, The bird's-eye view creating means sets the viewpoint closer to the road map as the traveling speed of the vehicle detected by the vehicle speed detecting means increases, and sets the distance between the current position on the road map and the viewpoint to the traveling speed. A vehicle navigation device characterized by being constant.