JPH0467893B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a current position display device for a moving object such as an automobile, which displays the current position and traveling trajectory of the moving object on a screen on which a map is displayed in advance.

BACKGROUND TECHNOLOGY Recently, as will be explained in detail later, when driving a car in an unfamiliar area, for example, in order to provide appropriate guidance so that the driver does not deviate from the planned driving course and get lost, As the vehicle travels, the distance detector detects the traveling distance according to the vehicle speed, and the direction detector detects the direction of travel and the amount of change thereof, and the current position of the vehicle on two-dimensional coordinates is sequentially determined from each detected value. This is determined through calculations, and the results are recorded and retained, and are displayed in continuous point information that changes moment by moment on a screen that displays a road map in advance, allowing the driver to confirm their current location. A device for displaying the current position of a moving object has been developed.

In such a device for displaying the current position of a mobile object, it is possible to prepare in advance a large number of maps for each region, one screen worth of area, and to selectively display a predetermined map on the screen depending on the region in which the vehicle is traveling. In addition, we prepare multiple maps of the same area with different scales as appropriate, and display the map with the optimal scale on the screen depending on the guidance situation at the time. The driving route can be displayed according to the current position calculated using a considerable scale factor.

However, ordinary maps are created using a plane projection method using graticules as a reference, but since the projection method is different for maps with a small scale and maps with a large scale, they can be used as a single coordinate system. It has become difficult to have common handling. Furthermore, in maps created using a plane projection method using graticules as a reference, the area surrounded by each graticule varies in size and shape depending on longitude and latitude. It has become difficult to commonly treat areas as one coordinate system.

In addition, maps with particularly large scales such as 1:50,000 or 1:25,000 are created using UTM coordinates, and for example, all of Japan is mapped to each location.
It is composed of multiple maps made up of UTM coordinate systems, but such maps only ensure consistency within each system and do not take into account the connections between systems at all. When traveling across the connecting parts of the system, the coordinates of the traveling route display must be converted from the previous UTM system to the new UTM system map that has been switched on the screen, and this process is difficult. It gets complicated.

Purpose The present invention was made in consideration of the above points, and
When displaying the current position of a moving object on a map displayed on the screen according to its scale, simple processing will always allow the current position of a moving object to be displayed on the map, even if the scale of the map changes or the map itself changes. An object of the present invention is to provide a current position display device for a moving body that can display a current position with high accuracy.

Structure In order to achieve the object, the present invention focuses on a mesh created by the graticule in a map created by a plane projection method using the graticule as a reference, and determines a reference point in the mesh, for example, the intersection of the mesh. The current position on the two-dimensional coordinates of the moving object, which changes from moment to moment, is converted to a position on the latitude-longitude coordinates, and the current position is displayed at an appropriate point based on the known latitude-longitude values. There is.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the basic configuration of a current position display device for a moving object according to the present invention, for example, a photoelectric type, electromagnetic type, or mechanical contact that outputs a pulse signal for each unit traveling distance according to the rotation of a car tire. A distance sensor 1 based on a formula or the like, a direction sensor 2 that outputs a signal proportional to the amount of change in direction as the car travels, which is composed of a gyroscope or the like that detects changes in angular velocity in the yaw direction, for example, and a pulse signal from the distance sensor 1. By counting the number and measuring the distance traveled by the vehicle, and by calculating the change in the direction of travel according to the output signal of the direction sensor 2, the position on the two-dimensional coordinates of the vehicle for each unit distance traveled is sequentially calculated. and a signal processing device 3 consisting of a CPU, program ROM, control RAM, etc., which performs centralized control of the entire system, and the ever-changing two-dimensional coordinates obtained by the signal processing device 3. A driving trajectory memory (RAM) 4 that sequentially stores location data and holds it as finite continuous location information corresponding to the current location of the vehicle, and a large amount of map information for each region and various scales in advance. A stored map information storage medium 5 and a storage medium reproducing device 6 that selectively reads necessary map information from the storage medium 5.
Then, a map image is displayed on the screen according to the read map information, and the current position of the vehicle, the previous travel trajectory, and the current direction of travel are displayed based on the position data stored in the travel trajectory storage device 4. In addition to giving operation commands to the display device 7 that updates and displays on the same screen every moment, and the signal processing device 3, it also selects and specifies the map to be displayed on the display device 7 and sets the starting point of the car on the displayed map. You can also change the display format settings, such as changing the direction of the displayed map and travel trajectory, shifting the display position, enlarging a portion of the map and travel trajectory, and selecting the display scale. It is configured by an operating device 8.

With this configuration, the selectively read map is displayed on the screen of the display device 7, and the signal processing device 3 displays the map as the vehicle travels from the starting point set on the map. X-Y according to the preset map scale
The current position (x, y) on the coordinates is calculated every moment, and the calculation results are sequentially sent to the travel trajectory storage device 4 to update the memory contents, and the memory contents can be read at any time. The image is output and sent to the display device 7. As a result, the display device 7 displays a display mark M indicating the current position of the vehicle on the map displayed on the screen, as shown in FIG.
1. A display mark M2 indicating the direction of travel of the vehicle at its current position and a travel trajectory display mark M3 from the starting point S to the current position are displayed in a simulated manner following the traveling state of the vehicle.

The above configuration and operation are the same as those of the conventional moving object current position display device described at the beginning.

In such a device for displaying the current position of a mobile object, for example, a laser disk memory is used as the map information storage medium 5, and each map of Japan divided into regions is divided into 1/25,600,000 to 25,000,000 parts. In addition to memorizing 11 types of scale rates in 1/2 increments up to 1/1000th, the latitude and longitude values at at least one intersection point of meshes based on graticules on each map are stored. The information is registered in the storage medium 5 in advance together with the corresponding map information as known information.

In addition, on the display screen of the display device 7, a frame is set that is the limit for displaying the current position of a moving object on the map displayed on the screen, and a signal is sent when the current position displayed on the screen exceeds the frame. The processing device 3 detects this and updates the map in the next travel area displayed on the screen according to the moving direction of the moving body at that time.

Therefore, in the present invention, when a predetermined map is selectively read out from the map information storage medium 5 and displayed on the screen of the display device 7, particularly under the control of the signal processing device 3, the mesh of the map is simultaneously displayed. The latitude-longitude values at the reference point are read out and recognized by the signal processing device 3.

In addition, the signal processing device 3 converts the current position on the two-dimensional coordinates obtained as described above to a position on latitude-longitude coordinates, and converts the converted position into a position approximately equal to that of the map displayed on the screen at that time. Considered as an offset from the reference point set in the center, 1° of latitude and longitude from the reference point position.
Calculate the length of the area into equal parts to find the position on the map, and plot the calculated position as the current position. At the same time, data of the plotted positions on the two-dimensional coordinates are sequentially stored in the travel trajectory storage device 4.

Furthermore, in the signal processing device 3, when the current position to be plotted exceeds the frame set on the screen, the next map is updated and displayed, and the latitude of the mesh reference point on the updated map is -
The same process as described above is performed according to the longitude value, and the current position on the map is plotted.

Specifically, as shown in Figure 3, the reference point is the intersection O located approximately in the center of the mesh formed by the longitude line lo and the latitude line la on each map, and the intersection O of the mesh is set as the reference point. Display each map individually so that they are centered on the screen. In the figure, F indicates a frame for map switching, which is set to be the display limit of the travel trajectory displayed on the screen.

When a map is displayed on the screen, the latitude and longitude values of the reference point O on that map are recognized, and when the current position of the moving object is updated, the current position on the converted latitude and longitude coordinates is recognized. The change due to unit travel of the mobile object is added to the latitude-longitude value of the position, and the location on the map of the updated current position is determined from the difference with the latitude-longitude value of the reference point O. , if the determined position is within the frame F, the current position is updated and displayed on the same map.

At that time, if the calculated position exceeds the frame F, an adjacent map corresponding to the moving direction of the moving object at that time is updated and displayed on the screen, and the reference point O on the updated map is displayed. The latitude and longitude values of O are re-recognized, and the location of the current location on the map is determined from the difference between the latitude and longitude values of the reference point O, and the current location is displayed on the new map. .

However, by adopting such a means of displaying the current position of a moving body according to the present invention, even when using a map of the UTM coordinate system that does not take into account the connection between systems, the screen Since the reference point O for each map of the UTM coordinate system displayed on the screen is treated as known, even if the moving trajectory progresses and the map displayed on the screen changes, the reference point O for each map displayed on the screen is Since the current position on the map is calculated and displayed each time, the current position of the moving object can be displayed with an accurate position and direction relative to the map displayed on the screen.

Also, by performing such processing,
Even if the size and shape of the maps in each area are different, such as maps created by a plane projection method based on graticules, the signal processing device 3 treats each map as having a common coordinate system. This makes it possible to easily display the travel locus corresponding to each map.

Furthermore, since the earth is spherical but the map is flat, errors caused by projection become particularly noticeable in small-scale maps, but according to the present invention, such errors can be absorbed and adapted to small-scale maps. Even if the user is using the map, the current location can be accurately displayed on the map.

Effects As described above, in the current position display device of a moving object according to the present invention, the current position of the moving object on the ever-changing two-dimensional coordinates is determined by sequential calculation, and the current position of the moving object is calculated according to the data of the determined current position. In a device for displaying the current position of a mobile object, map information is read out in advance from a map information storage medium and the current position of the mobile object is updated and displayed on the screen on which the map is displayed. The known latitude and longitude values of the reference point, which are stored in advance in the map information storage medium, are displayed on the screen, with one intersection located approximately at the center of each intersection of the graticules on the screen-sized map as the reference point. means for reading out the current position on the two-dimensional coordinates of the moving object according to the map in which it is located, and converting the current position of the moving object on the obtained two-dimensional coordinates into a position on the latitude-longitude coordinates, and reading the latitude-longitude values of the reference point of the map displayed on the screen. This method uses a method to calculate the current location on the map and display the current location.
When displaying a driving route on the map displayed on the screen according to its scale, simple processing allows the map to always be displayed on the screen even if the scale of the map changes or the map itself changes. On the other hand, it has an excellent advantage of being able to display the current position of a moving object with high precision.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the basic configuration of a current position display device for a moving object according to the present invention, FIG. 2 is a diagram showing an example of display contents on the current position display device for a moving object, and FIG. 3 1 is a diagram showing a correspondence relationship between a reference point in a map mesh displayed on a screen and a map switching frame set on the screen. 1... Distance sensor, 2... Direction sensor, 3...
Signal processing device, 4...Travel trajectory storage device, 5...
Map information storage medium, 6...Storage medium playback device, 7
...Display device, 8...Operation device, lo...Longitude line,
la...latitude line, O...reference point, F...frame.

Claims (1)

[Claims] 1 The current position on the two-dimensional coordinates of the moving body as it travels is determined by sequential calculations, and according to the data of the determined current position, map information is read out in advance from the map information storage medium and a map is displayed. In a current position display device for a moving object, the current position of the moving object is updated and displayed on a screen that has been updated.
The known latitude-longitude value of the reference point stored in advance in the map information storage medium is determined by using one intersection point approximately in the center of the intersection points of the graticules on the map displayed on the screen as the reference point. , a means for reading out a map according to the map displayed on the screen, and a means for converting the current position of the moving object on the obtained two-dimensional coordinates into a position on latitude-longitude coordinates, and a reference for the map displayed on the screen. 1. A current position display device for a moving body, characterized in that the current position on a map is calculated from the latitude and longitude values of a point and means for displaying the current position.