JPH03136199A - Guide starting picture display system for navigation device - Google Patents

Abstract

PURPOSE:To automatically set the direction of travel by drawing the direction of travel and a pattern showing the direction of travel together with the display of an intersection figure when an approach road is specified and drawing the pattern showing the direction of travel when the approach road is not specified. CONSTITUTION:The approach road to the intersection is discriminated by a direction indicator 19 composed of a magnetic sensor and based on the approach road, the guide starting picture of a display part 18 is automatically drawn so that the approach road to the intersection can be directed upward in the picture. Then, even at the intersection where a target object is a little, a driver can make approach without making an error in the direction. Further, road guide can be started in a 1 step when touching a start key 54. When the approach road to the starting intersection can not be specified to one by the error of the direction indicator 19, the intersection figure is drawn and the driver can easily identify the position of the car from the shape of the intersection. Thus, the approach direction to the intersection and the direction of travel from the intersection to a destination can be automatically displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a navigation device, and in particular, for displaying a route guidance start screen, the direction of approach to an intersection that is a departure point and the direction of progress from the intersection are displayed. The present invention relates to a guidance start screen display method for a navigation device that automatically determines a direction.

[Prior Art] When visiting a new place by car, in order to arrive at the destination without getting lost, it is necessary to thoroughly study the driving route using a road map or the like in advance.

In considering this driving route, it goes without saying that the driving route must first be selected, but in order to ensure that the selected route is followed without fail, the driving route must be marked with landmarks such as intersections where there are right and left turns, characteristic objects, etc. It is necessary to remember road information such as distance traveled. However, as the road network becomes more complex, people may forget the names of intersections they should turn on or landmarks when driving for the first time, or they may not be able to easily check them while driving.
If you miss the name of the intersection you are supposed to turn at or the landmarks that serve as landmarks, you may not know your current location, and not only will you not be able to smoothly follow the flow of traffic, but you will also end up stranded in the middle of the road.

Navigation devices provide route guidance so that people can safely drive to a new destination without the above concerns, and various types of navigation devices have been proposed in recent years. Some of them include those that set a route to a destination and display the road map and the set route on the display, and others that display information such as remaining distance, names, right and left turns, etc. of intersections to turn to ensure that the route can be followed without fail. In addition, there are some that display characteristic objects so that the route can be confirmed while driving, and others that provide voice guidance in addition to display information.

In such a navigation device, it is first necessary to set a route, but in order to do so, it is necessary to input a departure point as a guidance starting point and a destination.
When a departure point and a destination are input, a route search process is performed based on road information data around and between the departure point and destination, and an optimal route is set from among a plurality of routes. In addition, in the method previously proposed by the applicant, instead of setting a specific route from the starting point to the destination, there is also a method that sets the road and direction of travel to the destination at specific points such as each intersection. be. In this case, the current position is recognized by collecting driving information such as travel distance, steering angle, and intersections passed, and route guidance is provided by providing information on the road and direction set at the current position. Is going.

As described above, in a navigation device, the starting point must first be input, and conventionally, an intersection is often used as the starting point because it is necessary to specify the starting position on the road.

Once the destination and starting intersection are set in this way, a route search is performed and the direction of travel from the starting intersection is displayed on the display device. This is the guidance start screen in the navigation device, and as a display method for this guidance start screen, for example, an enlarged view of the vicinity of each intersection is prepared in advance as image data, and as shown in FIG. An enlarged view of the vicinity of the intersection input as the departure point is read out and displayed on the display screen as the north direction, and an arrow 50 indicating the direction of travel obtained as a result of the route search is overwritten and displayed on the enlarged view. A method has been proposed (Japanese Patent Laid-Open No. 62-51000). In the figure, 51 is the name of the intersection selected as the starting point, 52 is a mark indicating the north direction, 53 is a gas station mark as a landmark, and the "Start" button 54 is on the screen. Combined with the touch board placed on the front of the screen, it forms a so-called touch key.
The driver recognizes the intersection based on the information drawn on the screen, and when departing, inputs "start" to start driving guidance. However, when searching for a route in a navigation device, the direction of approach to the intersection is not taken into account, so the guidance start screen only shows the direction of travel from the intersection, but not the direction of the vehicle approaching the intersection. Therefore, the driver may sometimes misperceive the direction of travel. That is,
If a vehicle approaches from direction A in the figure, it will have to make a U-turn, if it approaches from direction B, it will have to turn right, if it comes from direction C, it will go straight, and if it comes from direction D, it will have to make a U-turn. will have to turn left, but the 7th
As shown in the figure, there is a problem in the intersection map with north facing upwards that even if a vehicle is near the intersection, it is not always clearly possible to identify which road on the drawn intersection map the vehicle is on. On the display, for example, when a vehicle is approaching from direction B, the arrow is drawn in the left direction, so it may be mistaken for a vehicle to turn left when it should have turned right.

Therefore, in order to prevent misidentification of the direction of travel at the starting intersection, the applicant made the intersection map displayed on the guidance start screen rotatable so that the direction in which the vehicle is approaching the intersection can be displayed upward. A guidance start screen display method was proposed (Japanese Patent Application No. 1983-227828). An outline of the display screen is shown in FIG. In FIG. 8, the intersection diagram is divided into a road network drawing area 1 and a function drawing area 2. In the road network drawing area 1, surrounding road networks and landmarks such as gas stations GS are drawn with the departure intersection in the center, and the function An intersection name 3, a message 4, and a touch key 5 are drawn in a drawing area 2. The touch keys 5 include a "rotate" key to rotate the intersection map, an "OK" key to confirm the display rotation angle of the intersection map, and a "start" key to start navigation. It is made to be able to do human power. Figures 8 (a), (b), and (c) show examples of drawings in which each approach road to an intersection is rotated so that it is facing downwards, and each time you touch the "Rotate" key, the image shown in Figure 8 (a) → (b) → (C)
The intersection map can be rotated as shown in →(a)→... When the intersection diagram with the desired rotation angle is obtained, the key to confirm the display state is "OK".
” key, and when the “OK” key is touched, the 8th
As shown in figure (d), the direction of travel from the intersection to the destination is drawn with an arrow, and the "rotation"
Key The “Start” key is displayed instead of the “OK” key. Therefore, by touching the "Rotate" key, the driver can rotate the intersection map so that the direction of approach to the intersection, that is, the direction of travel of the vehicle, faces upwards on the screen, and then click "OK". By touching the `` key, the direction of travel from the intersection to the destination can be drawn. If you do this, as shown in Figure (d), you will drive from the bottom of the screen to the top of the screen, enter the intersection, and if the arrow pointing to the right is pointing to the right, you will turn right, and if it is pointing to the left, you will turn left. All you have to do is select the road to travel in the same direction as the arrow drawn on the screen, so it matches the sense of driving the vehicle and makes it easier to recognize intersection landmarks, direction of travel, and relative positional relationships. Misidentification at intersections can be prevented.

[Problems to be Solved by the Invention] However, in the conventional guidance start screen display method, the intersection map is rotated using the "Rotate" key, and then the "O
The display rotation angle must be determined using the "K" key, which requires a large number of steps and is cumbersome. In addition, if there are few clear targets at intersections, especially at crossroads, or if the scenery at the crossroads is symmetrical as shown in Figure 9, it may be difficult to identify where your troops are at the intersection, and rO
There were cases where it was not possible to input the KJ key. This is especially noticeable at night.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a guidance start screen display method for a navigation device that can automatically display the direction of approach to an intersection and the direction of travel from the intersection to a destination. It is something to do.

[Means for Solving the Problems] In order to achieve the above object, the guidance start screen display method of the navigation device of the present invention sets a travel route based on a specified departure intersection and destination, and A navigation device that provides guidance, including a direction meter (19),
Search for an approach road to the departure intersection within a predetermined range centered on the direction measured by the direction meter (19).S1
2) When an approach road is specified, display an intersection map consisting of the surrounding road network with the approach road at the top of the screen, and draw a pattern indicating the approach direction and the traveling direction on the intersection map.S14 ), if the approach road is not specified, an intersection map consisting of the surrounding road network is displayed with a predetermined orientation toward the top of the screen, and a pattern indicating the direction of travel is drawn on the intersection map (S15). shall be.

[Action and Effect of the Invention] In the present invention, a direction meter (19) comprising a magnetic sensor is provided.
The approach road to the intersection is determined using
Drivers can not only proceed without making a wrong turn even at intersections where there are few targets, but also eliminate the hassle of having to touch the conventional "rotation" key (5). Route guidance can be started with one step of touching the key (54).

In addition, if the approach road to the starting intersection cannot be identified as one due to an error in the compass (19), an intersection diagram similar to that shown in Figure 7 with north at the top will be drawn. In this case, since the intersection has a unique shape, the driver can easily identify the position of his own army from the shape of the intersection, and there is no similar problem.

Furthermore, the direction meter (19) is generally prone to errors due to disturbances and requires various corrections to determine the direction, but in the present invention, it is used only for identifying the approach road. It is possible to tolerate an error of about ±45@, and no correction is required. Therefore, an inexpensive direction meter (19) can be used, and a direction meter (19) can be used.
9), it is possible to minimize the increase in cost due to the use of the method.

Note that the numbers assigned to the above configurations are for comparison with the drawings, and the configurations of the present invention are not limited to the same extent by these numbers.

[Example code] Examples will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the start screen display method of the navigation device according to the present invention.
In the figure, 11 is a distance meter, 12 is a rudder angle meter, 13 is an input section, 1
4 is an input decoding section, 15 is an input decoding table, 16 is a data processing control section, 17 is an image output control section, 18 is a display section,
19 is a compass, 21 is a navigation data file,
23 indicates a map data file.

The distance meter 11 measures the distance traveled by the vehicle,
For example, it may be a method that detects and counts the rotation of a wheel, or a method that detects acceleration and integrates it twice, but other measurement means may also be used.

The steering angle meter 12 detects whether or not the intersection has been turned. For example, an optical rotation sensor attached to the rotating part of the steering wheel or a rotating volume can be used. An attached angle sensor may also be used.

The input unit 13 may be a physical stick or a key touch panel, or it may be combined with the screen of the display unit 18 to display keys and menus on the screen and input from that screen.

■2 The input decoding unit 14 decodes the data input from the input unit 13 while referring to the input decoding table 15. For example, when setting a course, the current position and destination are input by code input. By referring to this input decoding table 15, the code is converted into current position data and destination data. Therefore, the input decoding table 15 is set in accordance with information about what kind of input is given from the input unit 13.

The data processing control unit 16 is the core of the navigation device, and when the current position and destination are set from the input unit 13, the data processing control unit 16 refers to the route search rules stored in the navigation data file 21. You can set a course, display a road map on the screen of the display unit 18, display a route guidance screen for intersections at which you should turn, and display other guidance information such as the remaining distance to the intersection. do. The map data file 23 stores map data for this purpose, ie, road network data, etc., and the image output control section 17 controls the output of images to the display section 18. Note that various route search methods have been proposed, and any of them may be adopted. In addition, the data processing control unit 16 uses RAM as a work area.
(not shown).

The display unit 18 is composed of a suitable display device such as a cathode ray tube (hereinafter referred to as CRT) or a liquid crystal display device, and as described above, a touch panel is arranged in front of the screen, and the touch panel and a button-shaped display are connected to each other. This makes it possible to form touch keys with

The direction meter 19 detects the direction in which the vehicle is traveling, and can be composed of a suitable magnetic sensor.

In the navigation device shown in FIG. 1, when the current position, that is, the starting point intersection and destination are input from the input unit 13 before traveling, the data processing control unit 16 reads route guidance rules from the navigation data file 21. Read and set the route. The data processing control unit 16 also calculates the position of the own army by taking in measurement information from the distance meter 11 and the steering angle meter 12, and displays a guide map of the course and current position etc. through the display unit 18, as well as characteristic objects on the way. Provide guidance at intersections, etc. For example, in the middle of a course with a long distance to the next intersection, an image of a feature that the driver is passing may be displayed on the screen to give the driver a sense of security that he or she has not deviated from the course. Alternatively, the guide map and the position of the own troops may be displayed to notify the running position on the course. Then, when an intersection approaches, an intersection map is drawn and output.

The map data file 23 stores various data such as destination data, road data, intersection data, and node string data.It can be used as long as it is a non-volatile storage device, but it cannot be installed in a vehicle. It is small and lightweight because it is available, it is unaffected by magnetism since the vehicle body may become magnetized, and access time is short.
Since the amount of road data, intersection data, etc. is enormous, it is necessary to titrate conditions such as large capacity.
sk --15=Read Only Memory) is preferably used.

Destination data is not directly related to the present invention, so the data structure will be omitted, but for example, many place names are written categorized into categories such as amusement park names, sightseeing spot names, company names, etc., and the location is also written by east longitude and north latitude. It is written. For example, when there is a road network consisting of intersection numbers I~■ and road numbers ■~■ as shown in Figure 2(a), the road data and intersection data are as shown in Figure 2(b) for the intersection data and the road data as shown in Figure 2(b). The node string data in Figure (C) has a data structure as shown in Figure (d).

As shown in FIG. 2(b), the intersection data corresponds to intersection numbers I to ■, and includes at least the smallest road number among the roads where the intersection is the starting point, and the intersection is the ending point. The smallest road number among the roads, the location of the intersection (east longitude, north latitude), the intersection name, the number of roads that enter the intersection, that is, the number of roads that end at the intersection, and the orientation of all the roads that enter. have information on.

B- Also, as shown in Figure (C), the road data includes at least the next road number among roads that have the same starting point and the next road among roads that have the same end point, corresponding to the road numbers ■ to ■. number, start point by intersection number, end point, node string pointer,
It has information on road length. As is clear from the figure, the next road number among roads with the same starting point and the next road number among roads with the same ending point can be generated by searching for the same number from the starting point and ending point using the intersection number. Can be done. Furthermore, the road length can also be determined by integrating the position information of the next node string data.

Then, the node string data is as shown in (d) of the same figure.
The number of nodes is at the beginning of the road data that the node string pointer points to, followed by node position (east longitude, north latitude) information for nodes corresponding to that number. In other words, a node string is configured for each road data. The illustrated example shows node strings of road numbers ■ and ■.

As is clear from the above data structure, the road number unit consists of a plurality of nodes. In other words, node string data is a set of data related to one point on a road, and if the connection between nodes is called an arc, a road is expressed by connecting each of multiple node strings with an arc. . For example, regarding the road number ■, the node string data AOOO can be accessed from the node string pointer of the road data, and it can be recognized that the road number ■ consists of 15 nodes.

For example, when focusing on an intersection number ■, for a course that starts from this point, first, the road number ■ is determined from the information of the road where the intersection data appears, and then the next road data with the same starting point is Road number @ is searched from the information of "Road number".

Then, the road number ■ and then ■ are searched from the same information regarding the road number [phase]. Since the road number ■ is the first road number, it can be determined that there are no surrounding roads with other road numbers.

This also applies to the end point. In this way, by using the intersection data and road data, it is possible to search for the road number for entering and exiting each intersection, and also to find the distance of the route connecting each intersection. Furthermore, by adding information such as prohibition of entry and prohibition of right/left turns to these data, the data can be used as information for detailed route searching.

Next, an example of processing by the guidance start screen display method of the navigation device according to the present invention will be described. FIG. 3 is a diagram showing the overall process flow for navigation performed by the data processing control unit 16, and FIG. 4 is a diagram showing the flow of the guidance start screen display process in the overall process.

First, the driver inputs a destination (Sl). For the input method, use any conventional and appropriate input method, such as inputting the code number of the destination using the numeric keypad or selecting the destination by touching the destination name displayed on the menu screen. be able to. Next, the driver inputs the current position (S2). This is an operation to input the intersection that will be the starting point.You can use any conventional input method such as inputting the code number of the intersection or inputting it by touching the intersection name 9- displayed on the menu screen. Can be adopted.

When the destination and current location are input, the data processing control unit 16 refers to the navigation data to search for a route from the current location to the destination (S3), and when the route search is completed, a guidance start screen is displayed. It is displayed on the screen of the display unit 18 (S4). Various route search methods are known.
Either method may be adopted. The guidance start screen display process in S4 is performed according to the flow shown in FIG. 4, and will be described later. When the driver observes the guidance start screen and recognizes the direction of travel, he inputs the start key to instruct route guidance as in the past, but on this condition, the data processing control unit 16 performs route guidance in S5. conduct. In this route guidance process, the data processing control unit 1
6, as described above, displays the course guide map and current position, provides guidance on characteristic objects on the way, and provides guidance on intersections. This is similar to conventional route guidance processing. When one route guidance is completed, the data processing control unit 16
- Similarly, the current position is tracked by capturing the detected values of the distance meter 11 and the steering angle meter 12 (S6), and if the current position matches the destination, it means that the destination has been reached. The navigation process ends, but if not, the process returns to S5 and the route guidance process and current location tracking process are repeated.

The above is the entire navigation process.Next, the guidance start screen display process 84 will be explained in detail with reference to FIG.

In the guidance start screen display process, the data processing control unit 1
6 reads the output of the direction meter 19 to detect the direction in which the vehicle is traveling, reads the intersection data of the departure intersection from the intersection data in the map data file 23 (Sll), and uses the direction detected in S10 as the center. A search is made for roads existing within a predetermined range (812). This is a process that identifies which road the vehicle is currently attempting to enter from among the roads entering the starting intersection.
Assuming that the vehicle is approaching from the road shown in [3], and the direction detected in S10 is the direction indicated by the arrow 30,
In S11, the data processing control unit 16 reads out the number of roads to enter and the direction of the road to enter from the intersection data shown in FIG. Find out how many roads are within the range of ±00 as the center. The angle θ is a numerical value indicating the error range of the compass 19, and a compass normally has a
This method has a relatively large error due to the influence of disturbances such as power lines, electric train feed lines, and the magnetism of vehicles passing near the vehicle, so find the number of roads that fall within the error range. It is. As a result of the road search in S12, in the case of Fig. 5(a), only the road with road number [phase] is searched as the approach road, but as shown in Fig. 5(b), the intersection with intersection number ■ is searched. When approaching from the road with the road number [phase], the direction of the road with the road number ■ is also included in the error range of ±00 centered on the detected direction 31, so the road search result in S12 is obtained. The road is
There are two roads, the road with road number ■ and the road with road number [phase], and it cannot be specified as one. In other words, in the case of FIG. 5(a), the data processing control unit 16 can recognize that the person is about to enter from the road with the road number [phase], but in the case of FIG. 5(b)
In this case, the data processing control unit 6 cannot discern whether the vehicle is attempting to enter from the road with road number ■ or the road with road number [phase]. Therefore, the data processing control unit 16 distinguishes between cases in which a single approach road can be specified and cases in which it is not possible to specify the approach road, and draws different guidance start screens for each case.

First, if a single approach road to the starting intersection can be identified as a result of the road search in S12, a guidance start screen is displayed in the first mode in S14, and if a single approach road cannot be identified, S15 The guidance start screen is displayed in the second mode.

In the guidance start screen display according to the first aspect, as shown in FIG. 6, the intersection map is automatically rotated and displayed so that the direction of travel of the vehicle is upward on the screen, and the An arrow indicating the direction of approach from the intersection and the direction of travel from the intersection obtained as a result of the route search are displayed. In order to display such a display, if an intersection map is prepared in advance as image data, the intersection map is created in a predetermined direction, for example, with north facing upward on both sides. The intersection map may be rotated by the angular difference between the orientation of the road identified as the road and the north direction, and arrows indicating the approach direction and the proceeding direction may be overwritten thereon. Note that since image rotation processing is well known, its details will be omitted. In addition, when drawing an intersection map using road data, intersection data, and node string data, first search for all roads that connect to the starting intersection, and then set the coordinates on the map consisting of east longitude and north latitude on the bitmap area. Convert to coordinates, set an appropriate width for each road, write an intersection diagram in the bitmap area so that the departure intersection is approximately in the center of the display area, and then overwrite the arrows indicating the approach direction and the direction of travel. . In order to set the approach direction toward the top of the screen, the direction of each road obtained from the node string data may be rotated by the difference between the direction of the approach road and the north direction, and then written in the bitmap area4. Alternatively, the orientation of the map data may be written in the bitmap area and then rotated. In this way, the intersection map shown in FIG. 6 can be drawn, and the driver can thereby easily recognize the direction of travel.

In addition, if the approach road cannot be identified as one, the second mode of guidance start screen is displayed at 815, but as in the past, this screen is similar to the one shown in Figure 7 in the north direction. The following screen will be displayed. In order to display such a screen, if an intersection map has been prepared in advance as image data, it is sufficient to display the image as is and overwrite the arrow indicating the direction of travel. When drawing using intersection data and node string data, search all roads connected to the starting intersection,
Convert the coordinates on the map consisting of east longitude and north latitude to coordinates on the bitmap area, set an appropriate width for each road, and draw an intersection map in the bitmap area so that the starting intersection is approximately at the center of the display area. All you have to do is write, then overwrite the arrow that shows the direction of travel.

The second aspect of the guidance screen displays only the direction of travel from the departure intersection obtained as a result of the route search, and does not indicate the direction of approach to the intersection. However, in cases where the approach road cannot be specified as one, , the road entering the intersection is direction meter 19
This is the case for intersections with special shapes such as three-way intersections and three-way intersections where there are multiple intersections within the error range of This is not an inconvenience because you can recognize which direction you should go from the arrow indicating the direction of travel.

As is clear from the above explanation, according to the present invention, if the approach road to the departure intersection can be identified based on the direction of the own vehicle measured with the compass, the approach direction is automatically displayed on the screen. Since an intersection map with a direction is displayed, the driver can clearly recognize the direction of travel even at crossroads where there is a high possibility of losing the vehicle's position. Additionally, if the approach road cannot be identified, an intersection map with a predetermined orientation, such as north facing up, is displayed. In this case, since the intersection has a special shape, the driver can Never lose sight of your army's position and direction of movement. Therefore, there is no need to operate the ``rotate'' key or the ``OK'' key as in the conventional case, and it is sufficient to simply operate the ``start'' key, so that the number of operational steps can be minimized.

Additionally, compass gauges generally have large errors due to external disturbances and require complex corrections to measure the compass with high precision; however, in the present invention, they are used only to identify approach roads, and cannot particularly determine the position of one's own troops. Since it is only necessary to identify the approach road at the most likely crossroads, there is a large margin of error, and operations such as starting from the intersection and destination are usually done with the vehicle stopped. Considering that the influence of external disturbances is relatively small when the vehicle is stopped, an error of about ±30' to 45° is acceptable, and although no correction is required, it is cost effective. increase can be kept to a minimum.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the guidance start screen display method of a navigation device according to the present invention, FIG. 2 is a diagram showing an example of the structure of map data, and FIG. 3 is a diagram showing the data processing control unit 1.
FIG. 4 is a diagram showing the flow of the guidance start screen display process in the overall process, and FIG. 5 is a diagram explaining the road search process. , FIG. 6 is a diagram showing an example of a guidance start screen display according to the first aspect, FIG. 7 is a diagram showing a display example of a conventional guidance start screen, and FIG. 8 is a diagram showing an example of another conventional guidance start screen display. FIG. 9 is a diagram for explaining problems in the conventional guidance start screen display. DESCRIPTION OF SYMBOLS 11... Distance meter, 12... Rudder angle meter, r3... Input section, 14... Input decoding section, 15... Input decoding table, 16... Data processing control section, 17...・Image output control unit, 18...Display unit, 19...Direction meter, 21.
... Navigation data file, 23... Map data file. 7 8 Fig. 5 (a) (b) Fig. 8 (a) (b) (c) (d) Fig.

Claims (1)

[Claims] (1) A navigation device that sets a travel route based on a designated departure intersection and destination and provides travel guidance, which is equipped with a direction meter and that travels within a predetermined range around the direction measured by the direction meter. An approach road to a certain departure intersection is searched, and when an approach road is specified, an intersection map consisting of the surrounding road network is displayed with the approach road at the top of the screen, and the approach direction and traveling direction are displayed on the intersection map. If the approach road is not specified, an intersection map consisting of the surrounding road network is displayed with a predetermined direction toward the top of the screen, and a pattern indicating the direction of travel is drawn on the intersection map. A guidance start screen display method for a navigation device, characterized by: