Navigation device, navigation system, and route guidance method

Abstract

Provided are a navigation device, a navigation system, and a route guidance method. Even when a plurality of intersections where a turn is required is close to each other in a guidance route, it is possible to effectively assist a user to move smoothly. The method comprises: a map display unit that displays a map on a first display device and displays a guidance route and a current position on the map; and a scale determination unit that determines the scale of the map displayed on the first display device, the scale determination unit lowering the scale as the current position approaches an intersection where a direction change is required along the guidance route, and enlarging the scale as the current position moves at the intersection.

Description

Technical Field

[0001] The invention relates to a navigation device, a navigation system and a path guiding method. Background Art

[0002] Patent Document 1 describes a navigation device that changes the scale of a displayed map to gradually enlarge a map including the current position and the intersection as the vehicle approaches an intersection where a right or left turn is required on a guidance route.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2003-269967

[0004] The guidance route displayed by the navigation device depends on the connection state of the roads, for example, right turns and left turns may be repeated at multiple intersections that are close to each other. In the case of a route that continuously turns at multiple intersections that are close to each other, the driver needs to obtain information on the route to the next intersection in advance when passing through an intersection.

[0005] However, in the conventional navigation device, as the vehicle approaches an intersection, the map including the current position of the vehicle and the intersection is gradually enlarged and displayed, and the displayed map may lack information on the route to the next intersection. As a result, the driver's preparations for the next intersection are delayed, which may hinder the vehicle's travel. Summary of the invention

[0006] In view of the above background, an object of the present invention is to effectively assist a user so that the user can move smoothly even when a plurality of intersections at which the user should turn exist close to each other on a guidance route.

[0007] One embodiment of the present invention is a navigation device that displays a guide route to a destination on a map, wherein the navigation device includes: a map display unit that displays a map on a first display device and displays the guide route and a current position on the map; a scale determination unit that determines the scale of the map displayed on the first display device, and as the current position approaches an intersection where a direction change is required along the guide route, the scale determination unit lowers the scale, and as the current position moves at the intersection, the scale determination unit enlarges the scale.

[0008] Another embodiment of the present invention is a navigation system comprising the navigation device of a vehicle and the first display device of the vehicle, wherein the navigation device further comprises a preceding vehicle information acquisition unit which acquires information of a preceding vehicle of the vehicle travelling within a prescribed distance from a current position, and the scale determination unit maintains the scale at a current value while the preceding vehicle is detected.

[0009] Another embodiment of the present invention is a path guidance method executed by a computer, comprising: a step of determining the scale of a map displayed on a display device; and a step of displaying a map showing a guidance path and a current position on the display device at the scale determined in the determining step, wherein in the determining step, the scale is reduced as the current position approaches an intersection where a direction change is required along the guidance path, and the scale is increased as the current position moves at the intersection.

[0010] Effects of the Invention

[0011] According to the present invention, even when a plurality of intersections at which a user should turn exist close to each other on a guidance route, it is possible to effectively assist the user and enable smooth movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram showing the configuration of a navigation device and a navigation system according to an embodiment of the present invention.

[0013] Figure 2 It is a diagram showing an example of the arrangement of the first display device and the second display device in the navigation system of the present invention.

[0014] Figure 3 This is a diagram showing an example of the scale setting of the map display when approaching an intersection where a turn is required on the guidance route.

[0015] Figure 4 This is a diagram showing an example of the scale setting of the map display when two intersections on the guidance route are separated.

[0016] Figure 5 This is a diagram showing an example of the scale setting of the map display when two intersections on the guidance route are close to each other.

[0017] Figure 6 A diagram showing an example of display on the first display device.

[0018] Figure 7 This is a diagram showing an example of display on the first display device when approaching a nearby intersection along the guidance route.

[0019] Figure 8 This is a flowchart showing the operation procedure of the navigation device.

[0020] Description of symbols

[0021] 100 ... navigation device, 102 ... vehicle, 104 ... network bus, 106 ... first display control device, 108 ... second display control device, 110 ... vehicle information acquisition device, 112 ... object detection device, 114 ... GPS receiving device, 116 ... remote communication device, 120 ... first display device, 122 ... second display device, 124 ... touch panel, 126 ... speed sensor, 128 ... object sensor, 130 ... speaker, 140 ... processing device, 142 ... storage device, 144…map information, 150…current position acquisition unit, 152…route search unit, 154…previous vehicle information acquisition unit, 156…map display unit, 158…scale determination unit, 160…navigation system, 200…instrument panel, 202…driver's seat, 203…speed display area, 204…map display area, 205…speed bar, 300, 304, 305…road, 301…vehicle position icon, 302…guidance route, 303, 306…direction indication icon. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 1 is a diagram showing the configuration of a navigation device and a navigation system according to an embodiment of the present invention. The navigation device 100 is mounted on a vehicle 102 or is connected to a vehicle 102 for use. In the present embodiment, the vehicle 102 is a four-wheeled vehicle.

[0023] The navigation device 100 operates together with various devices provided in the vehicle 102 via the network bus 104 . These devices may include a first display control device 106 , a second display control device 108 , a vehicle information acquisition device 110 , an object detection device 112 , a GPS receiving device 114 , and a remote communication device 116 .

[0024] The first display control device 106 and the second display control device 108 respectively control the screen display operations of the first display device 120 and the second display device 122. In this embodiment, the navigation device 100, the first display control device 106, the second display control device 108, the first display device 120, and the second display device 122 together constitute a navigation system 160.

[0025] Figure 2The figure shows an example of the arrangement of the first display device 120 and the second display device 122 in the interior of the vehicle 102 in the navigation system 160. The first display device 120 is arranged at a position of the instrument panel 200 in front of the driver's seat 202. In addition, the second display device 122 is arranged, for example, at the center of the instrument panel 200 in the vehicle width direction (left-right direction in the figure).

[0026] The first display device 120 is, for example, a liquid crystal display device, and under the control of the first display control device 106, displays various information related to the travel of the vehicle 102, including the speed of the vehicle 102 and a map. Figure 2 As shown, in the first display device 120 , a map display area 204 is provided in the speed display area 203 .

[0027] The second display device 122 is, for example, a liquid crystal display device having a touch panel 124 disposed on the display screen. The second display device 122 displays images and videos under the control of the second display control device 108, and outputs input information from the touch panel 124 to the second display control device 108. The second display control device 108 sends the input information from the touch panel 124 to other related devices via the network bus 104. The second display control device 108 may be, for example, a so-called smart screen interconnection system for performing music reproduction, video reproduction, etc.

[0028] The vehicle information acquisition device 110 detects the current speed of the vehicle 102 from at least the speed sensor 126, indicates the detected speed to the first display control device 106, and displays it on the first display device 120. The vehicle information acquisition device 110 can also calculate the instantaneous fuel consumption rate and / or the average fuel consumption rate based on the acceleration calculated from the time change of the detected speed, the travel distance of the vehicle 102, and the fuel consumption, and display them on the first display device 120.

[0029] The object detection device 112 detects an object in front of the vehicle 102 through the object sensor 128, and determines whether there is a preceding vehicle in front of the vehicle 102. The object sensor 128 may be, for example, a camera, a radar, and / or an optical radar provided on the front bumper of the vehicle 102. The object detection device 112 notifies the navigation device 100 of the presence or absence of the preceding vehicle in response to a request from the navigation device 100.

[0030] The GPS receiving device 114 receives GPS radio waves from GPS (Global Positioning System) satellites, and generates current position data indicating the current position (for example, latitude and longitude) of the vehicle 102 (ie, the navigation device 100 installed in the vehicle 102 ).

[0031] The remote communication device 116 is, for example, a TCU (Telematics Control Unit), and is a wireless communication device for connecting each device connected to the network bus 104 to the Internet or a telephone line.

[0032] The navigation device 100 includes a processing device 140 and a storage device 142. The storage device 142 is composed of, for example, a volatile and / or non-volatile semiconductor memory and / or a hard disk device, and stores map information 144. The processing device 140 is, for example, a computer having a processor such as a CPU (Central Processing Unit). The processing device 140 may also have a ROM (Read Only Memory) in which a program is written, a RAM (Random Access Memory) for temporarily storing data, and the like.

[0033] Furthermore, the processing device 140 includes a current position acquisition unit 150 , a route search unit 152 , a preceding vehicle information acquisition unit 154 , a map display unit 156 , and a scale determination unit 158 ​​as functional elements or functional units.

[0034] These functional elements of the processing device 140 are realized, for example, by executing a program by the processing device 140 as a computer. In addition, the computer program can be stored in any storage medium that can be read by a computer. Alternatively, all or part of the functional elements of the processing device 140 can be respectively constituted by hardware including one or more electronic circuit components.

[0035] The current position acquisition unit 150 receives the current position data from the GPS receiving device 114 and acquires the current position.

[0036] The route search unit 152 obtains the destination designated by the occupant of the vehicle 102 via the touch panel 124 of the second display device 122. Then, the route search unit 152 searches for a route from the current position obtained by the current position acquisition unit 150 to the destination according to the conventional technology, and determines a guidance route.

[0037] The preceding vehicle information acquisition unit 154 acquires information on whether there is a preceding vehicle traveling within a predetermined distance from the current position of the vehicle 102 from the object detection device 112 .

[0038] The map display unit 156 instructs the first display control device 106 to display a map on the first display device 120 , and displays the guidance route and the current position superimposed on the map.

[0039] The scale determination unit 158 ​​determines the scale of the map displayed by the map display unit 156 on the first display device 120. Specifically, the scale determination unit 158 ​​reduces the scale as the current position approaches an intersection where a direction change is required along the guide route, and increases the scale as the current position moves at the intersection. Hereinafter, unless otherwise specified, "intersection" refers to an intersection where a direction change is required along the guide route.

[0040] Here, in this manual, "reducing the scale" or "reducing the scale" means that the actual distance between two locations corresponding to 1 cm on the map displayed on the display screen becomes longer, and "enlarging the scale" means that the actual distance between two locations corresponding to 1 cm on the map displayed on the display screen becomes shorter.

[0041] When the interval distance between the intersection closest to the current position and the next intersection along the guidance path is less than a threshold distance, the scale determination unit 158 ​​starts to enlarge the scale of the current position when it moves to the above-mentioned nearest intersection from a position closer to the front along the guidance path, compared with when the above-mentioned interval distance is greater than the above-mentioned threshold distance.

[0042] In addition, when the interval distance between the intersection closest to the current position and the next intersection along the guidance path is less than a threshold distance, the scale determination unit 158 ​​reduces the upper limit value of the increase in scale when the current position moves at the nearest intersection, compared to when the interval distance is greater than the threshold distance.

[0043] However, the scale determination unit 158 ​​maintains the scale at the current value while the preceding vehicle is detected.

[0044] Figure 3 1 is a diagram showing an example of a change in the scale set by the scale determination unit 158 ​​when approaching an intersection on the guidance route where a turn is required. Figure 3 In FIG. 1 , the horizontal axis is the distance along the guidance route, and the entry position of the nearest intersection is set as the origin O. In addition, the vertical axis is the scale value, and the scale at the position before the intersection at a distance D10 is Sf11. Sf11 is, for example, a value set by the driver during the previous driving.

[0045] When the vehicle 102 reaches a position close to the intersection by a distance D10, the scale determination unit 158 ​​reduces the scale from Sf11 to Sf12. Thereafter, when the vehicle reaches a position close to the intersection by a distance D11 and D12, the scale determination unit 158 ​​reduces the scale in stages to Sf13 and Sf14. Thus, in the first display device 120, as the vehicle 102 approaches, the intersection where the vehicle should turn is displayed in an enlarged manner, so that the driver of the vehicle 102 can easily determine the nearest intersection where the vehicle needs to turn even when the vehicle 102 is driving on a road with many intersections.

[0046] In addition, the values ​​of the distances D10 , D11 , and D12 and the values ​​of the scales Sf12 , Sf13 , and Sf14 corresponding thereto can be predetermined and stored in the storage device 142 .

[0047] Figure 4 This is a diagram showing an example of the change in scale determined by the scale determination unit 158 ​​during the period before the vehicle 102 approaches the intersection and passes through the intersection when the distance between the intersection closest to the current position and the next intersection along the guidance route is greater than the threshold distance. The threshold distance may be, for example, in the range of 100 m to 200 m. Figure 4 In the middle, the horizontal axis is Figure 3 The distance along the guide path is also expressed, but it should be noted that the scale is relative to Figure 3 The horizontal axis is enlarged in the left and right directions of the illustration. Figure 4 The vertical axis and Figure 3 Likewise, represents the value of the scale.

[0048] exist Figure 4 In the example, when the vehicle 102 enters the intersection and reaches a position at a distance D21 from the intersection entry position, the scale determination unit 158 ​​starts to enlarge the scale, firstly, enlarging the scale from Sf14 to Sf21. Hereinafter, the position where the scale determination unit 158 ​​starts to enlarge the scale when the vehicle 102 passes through the intersection is referred to as the enlargement start point PS. Figure 4 In the example, D21 is the expansion start point PS. After that, when the vehicle 102 continues to move in the intersection and reaches a position that is a distance D22 and a distance D23 from the entry position of the intersection, the scale determination unit 158 ​​increases the scale from Sf21 to Sf22 and SfL1.

[0049] SfL1 is a value pre-determined as the upper limit value SfL of the scale value when the scale is enlarged when passing through an intersection. In this case, every time the travel distance in the intersection increases by a certain incremental distance, the scale determination unit 158 ​​adds a certain incremental value to the scale value, so that the scale is increased in stages until the above-mentioned enlargement upper limit value SfL1 is reached. The above-mentioned incremental distance and the incremental value of the scale can be pre-determined and stored in the storage device 142.

[0050] Through Figure 4 By changing the scale of the map displayed on the first display device 120 in this way, the driver can grasp the path after passing the intersection at a farther position as the driver turns at the intersection, and can therefore perform early preparatory actions for driving after leaving the intersection. Thus, the navigation device 100 can assist the driver to enable smooth driving after leaving the intersection.

[0051] Figure 5 This is a diagram showing an example of the change in scale determined by the scale determination unit 158 ​​until the vehicle 102 approaches the intersection and passes through the intersection, when the distance between the intersection closest to the current position and the next intersection along the guidance route is less than the threshold distance and the two are close to each other. Figure 5 In the figure, the horizontal and vertical axes are Figure 4 same.

[0052] exist Figure 5 In FIG. 1 , when the vehicle 102 approaches the intersection and reaches a position before the entrance position of the intersection by a distance D31, the scale determination unit 158 ​​starts to enlarge the scale. Figure 5 In the diagram, the position before the entrance position of the intersection by distance D31 is the enlargement start point PS. After that, the scale determination unit 158 ​​gradually enlarges the scale to the enlargement upper limit value SfL2 until the vehicle 102 leaves the intersection. Specifically, the scale determination unit 158 ​​enlarges the scale from Sf14 to Sf31 at the enlargement start point PS, i.e., the position by distance -D31, and then enlarges the scale from Sf31 to the enlargement upper limit value SfL2 at a position by distance D32 past the entrance position of the intersection.

[0053] In this case, please note that the position of the enlargement starting point PS (the position of distance -D31) and Figure 4 Compared to the position of the enlargement start point PS (the position at distance D21) when the intersection is far away, it is located closer along the guidance route. Figure 5 The upper limit of the amplification SfL2 is less than Figure 4 The upper limit value of amplification SfL1 in .

[0054] The value of the distance D31 corresponding to the enlargement start point PS and the value of the expansion upper limit SfL2 can be predetermined and stored in the storage device 142. In addition, the scale determination unit 158 ​​can use the pre-stored incremental distance and incremental value, and when the travel distance in the intersection increases by the incremental distance, add the incremental value to the scale value, and increase the scale in stages until the scale reaches the enlargement upper limit SfL2.

[0055] like Figure 5 As shown, in the navigation device 100, when the interval distance between the nearest intersection and the next intersection is less than the threshold distance, and when the interval distance is greater than the threshold distance ( Figure 4 ), the enlargement start point PS is set at a position closer to the front along the guidance path. As a result, in the navigation device 100, when multiple intersections that should be turned exist closer to each other, the path to the next intersection will be displayed earlier on the map display, which can enable the driver to quickly prepare for action.

[0056] In addition, if Figure 5 As shown, in the navigation device 100, when the interval distance between the nearest intersection and the next intersection is less than the threshold distance, the enlargement upper limit value SfL is set to a smaller value than when the interval distance is greater than the threshold distance. As a result, in the navigation device 100, it is possible to prevent the driver's intuitive recognition of the path to the next intersection from being reduced due to a significant increase in the scale of the map (i.e., a wider map display) when passing through an intersection.

[0057] However, as described above, the scale determination unit 158 ​​maintains the scale at the current value while the preceding vehicle is detected. Thus, when there is a preceding vehicle, the scale of the map display is kept constant, thereby suppressing changes in the map display. As a result, in the navigation device 100, it is possible to prevent the driver from focusing on the display of the first display device 120 and thereby prevent the driver's attention from being reduced to the preceding vehicle.

[0058] In this embodiment, in order to more effectively assist the driver in smooth driving when the nearest intersection is close to the next intersection, the map display unit 156 increases the proportion of the display area of ​​the map in the first display device 120 when the intersection is close compared to when the intersection is not close.

[0059] Figure 6 is an example of a map display on the first display device 120 when the intersection is not approaching, showing Figure 2The speed display area 203 including the map display area 204 in the first display device 120 shown in the figure. In the example shown in the figure, the map display area 204 is provided inside the numerical values ​​indicating the speed values ​​arranged in a circle in the speed display area 203. In the map displayed inside the map display area 204, for example, roads 300 in the urban area constructed in a grid shape, a vehicle position icon 301 indicating the current position of the vehicle 102 as the vehicle, and a guide path 302 drawn with a thick line are displayed. In addition, a direction indication icon 303 indicating that the vehicle should turn right at the intersection ahead is also displayed on the above map. In addition, the current speed of the vehicle 102 is indicated by, for example, an arc-shaped speed bar 205 displayed outside the speed value arranged in a circle.

[0060] Figure 7 This is an example of a map display on the first display device 120 when an intersection is approaching. Figure 7 In, with Figure 6 Likewise, it is shown Figure 2 The speed display area 203 including the map display area 204 in the first display device 120 is shown. Figure 6 Compared with the example of the case where the intersection is not close, Figure 7 , the size of the map display area 204 is set larger.

[0061] Specifically, in Figure 7 In the map display area 204, no speed value is displayed, and the map display area 204 is set larger to reach the vicinity of the radial speed scale lines set in the speed display area 203. Moreover, inside the expanded map display area 204, except for Figure 6 In addition to the map displayed inside the map display area 204, two roads 304 and 305 extending in the vertical direction of the figure and a direction indication icon 306 indicating that the driver should turn right and then turn left at the intersection ahead are additionally displayed.

[0062] In this way, in the navigation device 100, when intersections are close to each other, a map of a wider range is displayed on the first display device 120, so that the predictability of the driving environment can be improved and the driver can feel at ease.

[0063] In the present embodiment, the map display unit 156 further displays a map showing the guidance route and the current position on the second display device 122 at a scale different from that of the map displayed on the first display device 120. Thus, since maps of different scales are displayed on the two display devices, the driver can recognize the details of the route to the next intersection through one display device, and can also obtain route information of a wider range from the other display device, thereby improving the sense of security.

[0064] In addition, when the interval distance between the intersection closest to the current position and the next intersection along the guidance path is less than the threshold distance, the map display unit 156 displays a map including the guidance path, the current position, and the next intersection of the nearest intersection on the second display device 122. Thus, even when a plurality of intersections to be turned are separated to a certain extent (for example, at intervals of about 50m, 100m, or 200m), the driver can recognize the details of the path near the current intersection through the first display device 120, and at the same time obtain information about the path to the next intersection through the second display device 122, thereby further improving the sense of security.

[0065] Next, follow Figure 8 The flowchart shown explains the procedure of route guidance using the first display device 120 in the navigation device 100 . Figure 8 The processing shown is started when the power of the navigation device 100 is turned on, and is ended when the power of the navigation device 100 is turned off.

[0066] When the process starts, first, the route search unit 152 determines whether a destination is input (S100). The destination is input, for example, via the touch panel 124 of the second display device 122. If no destination is input (S100, No), the route search unit 152 returns to step S100 and waits for the destination to be input.

[0067] On the other hand, when the destination is input (S100, Yes), the route search unit 152 obtains the current position from the current position acquisition unit 150 and determines the guidance route from the current position to the destination. Then, the map display unit 156 displays a map showing the current position and the guidance route on the first display device 120, for example, using a predetermined default scale value, and starts route guidance (S102).

[0068] Next, the map display unit 156 obtains the current position from the current position acquisition unit 150 at a predetermined time interval, and updates the map display of the first display device 120 as the current position moves (S104). In addition, the map display unit 156 determines whether the current position has reached the destination (S106). Then, when the current position has reached the destination (S106, yes), the map display unit 156 ends the route guidance and returns the process to step S100.

[0069] On the other hand, when the current position has not reached the destination (S106, No), the map display unit 156 determines whether the current position is within a predetermined distance from the intersection (for example, Figure 3Then, when the current position is not close to the range of the predetermined distance from the intersection (S108, No), the map display unit 156 returns to step S104 and repeats the process.

[0070] On the other hand, when the current position is within a predetermined distance from the intersection (S108, Yes), the scale determination unit 158 ​​determines the distance between the current position and the intersection by, for example, Figure 3 In the manner shown, the scale is gradually reduced as the intersection approaches ( S110 ). Accordingly, the map display unit 156 gradually reduces the scale of the map displayed on the first display device 120 .

[0071] Next, the scale determination unit 158 ​​determines whether the scale gradually reduced has reached the lower limit value before entering the intersection (for example, Figure 3 Then, when the scale does not reach the above-mentioned lower limit value (S112, No), the scale determination unit 158 ​​returns to step S110 to repeat the process.

[0072] On the other hand, when the scale reaches the lower limit value (S112, Yes), the scale determination unit 158 ​​sets the scale enlargement start point PS and the enlargement upper limit SfL to be respectively set as default. Figure 4 Next, the scale determination unit 158 ​​determines whether the distance between the nearest intersection and the next intersection is close to a range less than a predetermined threshold distance (S116). Then, when the nearest intersection and the next intersection are close to each other (S116, yes), the scale determination unit 158 ​​resets the scale enlargement start point PS and the enlargement upper limit SfL to Figure 5 ~D31 and SfL2(S118).

[0073] Then, the scale determination unit 158 ​​gradually reduces the scale of the map display as the current position approaches the nearest intersection (S120). On the other hand, in step S116, when it is determined that the nearest intersection is not close to the next intersection (S116, No), the process is directly transferred to step S120.

[0074] Next, the scale determination unit 158 ​​determines whether the current position has reached the enlargement start point PS (S122). If the current position has not reached the enlargement start point PS (S122, No), the scale determination unit 158 ​​returns to step S122 and waits for the current position to reach the enlargement start point PS.

[0075] On the other hand, when the current position reaches the enlargement start point PS (S122, Yes), the scale determination unit 158 ​​enlarges the scale in stages (S124). Next, the scale determination unit 158 ​​determines whether the scale has reached the enlargement upper limit value SfL (S126). Then, when the scale has not reached the enlargement upper limit value SfL (S126, No), the scale determination unit 158 ​​returns to step S124 and repeats the process.

[0076] On the other hand, when the scale reaches the enlargement upper limit value SfL (S126, yes), the scale determination unit 158 ​​maintains the scale at the current value (S128), and determines whether the current position has left the above-mentioned nearest intersection (whether it has separated) (S130). Then, when the current position has not left the above-mentioned nearest intersection (S130, no), the scale determination unit 158 ​​returns to step S128 and repeats the process. On the other hand, when the current position has left the above-mentioned nearest intersection (S130, yes), the scale determination unit 158 ​​transfers the process to step S104.

[0077] In addition, the present invention is not limited to the configurations of the above-described embodiment and its modified examples, and can be implemented in various forms within the scope not departing from the gist of the invention.

[0078] For example, in the above-described navigation device 100 , the route search unit 152 performs a route search, but the route search may be performed in another computer such as a server that can communicate via the remote communication device 116 .

[0079] In addition, in the navigation device 100, route guidance is performed by the first display device 120 or the first display device 120 and the second display device 122, but route guidance may be further performed using voice guidance using the speaker 130 connected to the navigation device 100. For example, when a plurality of intersections exist continuously at an interval distance less than a threshold distance, the navigation device 100 can output voice guidance indicating that the intersections appear continuously through the speaker 130.

[0080] In addition, in the navigation device 100, the scale is reduced and enlarged stepwise when passing through an intersection, but the scale may be reduced and enlarged continuously.

[0081] The above-mentioned navigation device 100 can be realized by a portable terminal such as a smartphone that can be connected to the network bus 104 via an appropriate interface device. Such a navigation device can be realized by executing a dedicated application program in the above-mentioned portable terminal.

[0082] The navigation device 100 implemented by such a portable terminal may use a display device generally provided in the portable terminal as the first display device 120, and may operate independently without being connected to the network bus 104 and removing some functions such as using the second display device 122. In this case, the current position acquisition unit 150 may acquire the current position of the portable terminal as the navigation device 100 through a GPS receiver generally provided in the portable terminal.

[0083] [Structure supported by the above-mentioned embodiment]

[0084] The above-mentioned embodiment supports the following structure.

[0085] (Structure 1) A navigation device that displays a guide route to a destination on a map, wherein the navigation device displays a guide route to a destination on a map, wherein the navigation device includes: a map display unit that displays a map on a first display device and displays the guide route and a current position on the map; a scale determination unit that determines the scale of the map displayed on the first display device, the scale determination unit lowering the scale as the current position approaches an intersection where a direction change is required along the guide route, and enlarging the scale as the current position moves at the intersection.

[0086] In the navigation device of Configuration 1, even when a plurality of intersections at which the driver should turn exist close to each other on the guidance route, the driver can be effectively assisted to move smoothly.

[0087] (Structure 2) A navigation device according to Structure 1, wherein, when the interval distance between the intersection closest to the current position and the next intersection along the guidance path is less than a threshold distance, the scale determination unit begins to enlarge the scale when moving at the nearest intersection at a position closer to the front along the guidance path, compared to when the interval distance is greater than the threshold distance.

[0088] According to the navigation device of the second configuration, when a plurality of intersections at which the driver should turn are closer together, the route to the next intersection can be displayed earlier, allowing the driver to quickly prepare for action.

[0089] (Structure 3) A navigation device according to Structure 1 or 2, wherein, when the interval distance between the intersection closest to the current position and the next intersection along the guidance path is less than a threshold distance, the scale determination unit reduces the upper limit value of the scale that is enlarged when moving to the nearest intersection, compared to when the interval distance is greater than the threshold distance.

[0090] According to the navigation device of Configuration 3, when a plurality of intersections at which the driver should turn are closer together, it is possible to prevent the driver's intuitive perception of the route to the next intersection from being reduced due to a large increase in the scale of the map when passing through the intersection.

[0091] (Structure 4) A navigation system comprising the navigation device according to any one of claims 1 to 3 and the first display device of the vehicle, wherein the navigation device further comprises a preceding vehicle information acquisition unit which acquires information of a preceding vehicle of the vehicle travelling within a prescribed distance from a current position, and the scale determination unit maintains the scale at a current value while the preceding vehicle is detected.

[0092] According to the navigation system of Configuration 4, when there is a preceding vehicle, the scale of the map display is kept constant, thereby suppressing changes in the map display. As a result, it is possible to prevent the driver from focusing on the first display device and thus prevent the driver from losing attention to the preceding vehicle.

[0093] (Structure 5) A navigation system according to Structure 4, wherein, when the interval distance between the intersection closest to the current position and the next intersection along the guidance path is less than a threshold distance, the map display unit increases the proportion of the area displaying the map in the first display device compared to when the interval distance is greater than the threshold distance.

[0094] According to the navigation system of configuration 5, a map covering a wider range can be displayed even at the same scale, thereby improving the predictability of the driving environment and providing the driver with a sense of security.

[0095] (Structure 6) The navigation system according to claim 4 or 5, wherein the first display device is provided on a dashboard of the vehicle in front of a driver's seat and displays at least a speed and a map of the vehicle.

[0096] According to the navigation system of Configuration 6, the map is displayed together with the vehicle speed at a position that is easily visible from the driver who is looking forward, so the driver can easily recognize the route to the next intersection.

[0097] (Structure 7) The navigation system according to Structure 6, wherein the first display device displays the map in a meter display area indicating a speed of the vehicle.

[0098] According to the navigation system of Configuration 7, the map is displayed in an area overlapping with the display of the vehicle speed at a position that is easily visible from the driver looking forward, so the driver can more easily recognize the route to the next intersection.

[0099] (Structure 8) A navigation system according to Structure 5, wherein the map display unit displays a map showing the guidance route and the current position on a second display device different from the first display device provided on the vehicle at a scale different from that of the map displayed on the first display device.

[0100] According to the navigation system of configuration 8, maps with different scales are displayed on two display devices, so the driver can recognize the details of the route to the next intersection and can also obtain route information in a wider range, thereby improving the sense of security.

[0101] (Structure 9) A navigation system according to Structure 8, wherein the map display unit displays a map including the guidance path, the current position, and the next intersection on the second display device when the interval distance between the intersection closest to the current position and the next intersection along the guidance path is less than a threshold distance.

[0102] According to the navigation system of Structure 9, even when multiple intersections where turns are to be made are separated to a certain extent (for example, at intervals of about 50m, 100m, or 200m), the driver can identify the details of the path near the current intersection through the first display device, and at the same time can obtain information about the path to the next intersection through the second display device, thereby further enhancing the sense of security.

[0103] (Structure 10) The navigation system according to Structure 8 or 9, wherein the second display device is provided at a center portion of the instrument panel in the vehicle width direction.

[0104] According to the navigation system of configuration 10, the driver can recognize the map displayed on the second display device without greatly moving his / her sight.

[0105] (Structure 11) A route guidance method, executed by a computer, comprises: a step of determining the scale of a map displayed on a display device; and a step of displaying a map representing a guidance route and a current position on the display device at the scale determined in the determining step, wherein in the determining step, the scale is reduced as the current position approaches an intersection where a direction change is required along the guidance route, and the scale is increased as the current position moves at the intersection.

[0106] According to the route guidance method of configuration 11, even when a plurality of intersections at which the driver should turn exist close to each other on the guidance route, it is possible to effectively assist the driver to move smoothly.

Claims

1. A navigation device that displays a guide route to a destination on a map, wherein: The navigation device comprises: a map display unit that displays a map on the first display device and displays the guide route and the current position on the map; a scale determination unit for determining a scale of the map displayed on the first display device, The nearest intersection along the guidance path where a direction change is required is defined between an entry position and an exit position of the intersection, When the current position reaches a position before the entry position of the nearest intersection at a first prescribed distance, the scale determination unit lowers the scale, and as the current position moves from the position before the entry position of the nearest intersection at the first prescribed distance and approaches the entry position of the nearest intersection, the scale determination unit further lowers the scale, and when the current position enters the nearest intersection from the entry position and the current position reaches a position within the intersection at a second prescribed distance from the entry position of the nearest intersection, the scale determination unit enlarges the scale, and as the current position moves in the nearest intersection from the position within the intersection at the second prescribed distance from the entry position of the nearest intersection to the exit position, the scale determination unit further enlarges the scale.

2. The navigation device according to claim 1, wherein: When the interval distance between the intersection closest to the current position and the next intersection along the guide path is less than a threshold distance, the scale determination unit begins to enlarge the scale when moving at the nearest intersection at a position closer to the front along the guide path, compared to when the interval distance is greater than the threshold distance.

3. The navigation device according to claim 1 or 2, wherein When the interval distance between the intersection closest to the current position and the next intersection along the guidance path is less than a threshold distance, the scale determination unit reduces the upper limit value of the scale enlarged when moving to the nearest intersection, compared to when the interval distance is greater than the threshold distance.

4. A navigation system comprising the navigation device according to any one of claims 1 to 3 disposed in a vehicle and the first display device disposed in the vehicle, wherein: The navigation device further includes a preceding vehicle information acquisition unit that acquires information about a preceding vehicle of the vehicle that is traveling within a predetermined distance from a current position. The scale determination unit maintains the scale at a current value while the preceding vehicle is detected.

5. The navigation system according to claim 4, wherein: When the interval distance between the intersection closest to the current position and the next intersection along the guidance path is less than a threshold distance, the map display unit increases the proportion of the area displaying the map in the first display device compared to when the interval distance is greater than the threshold distance.

6. The navigation system according to claim 4 or 5, wherein: The first display device is disposed on a dashboard of the vehicle in front of a driver's seat and displays at least a speed and a map of the vehicle.

7. The navigation system according to claim 6, wherein: The first display device displays the map in a meter display area indicating the speed of the vehicle.

8. The navigation system according to claim 5, wherein: The map display unit displays a map showing the guidance route and the current position on a second display device different from the first display device provided in the vehicle at a scale different from that of the map displayed on the first display device.

9. The navigation system according to claim 8, wherein: When the interval distance between the intersection closest to the current position and the next intersection along the guidance route is less than a threshold distance, the map display unit displays a map including the guidance route, the current position, and the next intersection on the second display device.

10. The navigation system according to claim 8 or 9, wherein: The second display device is provided at a center portion of the instrument panel in a vehicle width direction.

11. A path guidance method, executed by a computer, comprising: The step of determining the scale of the map displayed on the display device; as well as a step of displaying a map showing the guidance route and the current position on the display device at the scale determined in the determining step, The nearest intersection along the guidance path where a direction change is required is defined between an entry position and an exit position of the intersection, In the determination step, when the current position reaches a position before the entry position of the nearest intersection at a first prescribed distance, the scale is lowered; as the current position moves from the position before the entry position of the nearest intersection at the first prescribed distance and approaches the entry position of the nearest intersection, the scale is further lowered; when the current position enters the nearest intersection from the entry position and the current position reaches a position within the intersection at a second prescribed distance from the entry position of the nearest intersection, the scale is enlarged; as the current position moves in the nearest intersection from the position within the intersection at the second prescribed distance from the entry position of the nearest intersection to the exit position, the scale is further enlarged.

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