JPS59195791A - Running information display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information display device for displaying the traveling position of a vehicle such as an automobile on a display.

This type of conventional device uses a travel distance detector such as an electromagnetic pickup and a travel direction detector using a magnetic sensor to convert the travel distance and travel direction into electrical signals, and a control circuit using a microcomputer etc. There are devices that process and calculate these electrical signals and display the driving trajectory and current location on a display such as a CRT. It was possible to check whether the vehicle had followed the route and its current location by referring to the map.

However, although the above-mentioned conventional device can calculate and display the travel trajectory from the signals obtained from the travel distance detector and the direction detector, it is difficult to determine the correspondence between the travel trajectory and the roads on the map. However, there were operational drawbacks, such as the need to place a map sheet on a transparent sheet over the display. As a method to eliminate such drawbacks, a method has been proposed in which the map itself is displayed on a display, and the current position and travel trajectory of the vehicle are displayed superimposed on the displayed map. However, there is a possibility that the azimuth detector itself may make false detections due to disturbances, which may cause the display of the vehicle's travel trajectory or current position to malfunction.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and even if there is some erroneous detection in the direction detector, the current position or traveling trajectory of the vehicle will be displayed on the map displayed on the display. It is an object of the present invention to provide a driving information display device that can display information accurately.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and in the figure, reference numeral 1 indicates a traveling distance sensor that generates a signal with a frequency proportional to the traveling speed as the vehicle (not shown) travels. 2 is an azimuth detector that detects the traveling direction of the vehicle and outputs a full azimuth signal; 3 is a map memory that stores information such as roads on the map; 4 is a map information provided by the map memory 3; A travel trajectory display device (hereinafter referred to as a display device) 5 for displaying the travel trajectory, etc. reads data from the map memory 3, displays a map on the display device 4, and calculates the vehicle travel trajectory and current position. A control circuit 6 for displaying on the display 4 is a current position marker moving device for moving the marker Mi for displaying the entire current position of the vehicle displayed on the display 4 to an appropriate position.

Generally, the direction detector 2 may be a method of measuring the direction of geomagnetism or a method of using a gyro.
The method for measuring the direction of geomagnetism will be explained below.

However, even if other methods such as the above-mentioned gyro are used, the principle of calculating the running trajectory is substantially the same.

Now, as the direction detector 2, a magnetic sensor having two orthogonal detection axes is used, one of the two detection axes is aligned with the traveling direction of the vehicle 7, and all other detection axes are In the above configuration, the direction detector 2t is installed at an arbitrary position on the vehicle 7, such that it is placed in a horizontal plane perpendicular to the traveling direction of the vehicle 7.
A case where the vehicle 7 is placed so as to form an angle will be explained.

In this case, when the magnitude of the horizontal component of geomagnetism is 5H,
Magnetic field components HU and Hv in the two detection axis directions of the direction detector 2
are respectively HU = Kt Hcosθ.

It is given by Hy = K2Hsinθ. Here! ,
K2 is a constant determined by the structure of the vehicle, and 2 is approximately equal to Ks.

In addition, in the following explanation, for the sake of simplicity, Kl= and 2='
However, this does not result in loss of film properties. Now, when the above-mentioned magnetic field is applied to the orientation detector 2, two electrical output signals E obtained from the orientation detector 2
U and Ev are respectively ETJ=AHU=AK' Hcos
θ, Ey = AHy = AK' Hsin θ.

Here, A is a constant related to the sensitivity of the direction detector 2. In the above formula, if you replace AK'= with h "U" KHC
ogθ, Ey = KHsinθ. As shown in FIG. 2, the coordinate axes are set so that the X axis corresponds to the north, and the Y-i axis corresponds to the north, and the X axis corresponds to the east. Now, in the state shown in FIG. 2, when the vehicle 7 moves by a minute distance d in the direction of travel, in the X direction,
If the respective movement amounts in the Y direction are △X and Δy, Δ
X and Δy are given by the following equations.

△x = d sin θ, Δy = d cos θ
(1) Also, EU = KHcosθ, B
y = K) From the relational expression from l sin θ, cos θ = E
Ushio 11 Takumi ■, sin θ Engineering Ev/Niichiko]7, and from equation (1).

Therefore, the position (x, y) when the vehicle 7 moves while changing direction is given by the following equation.

Here, ■a is an integral with respect to the traveling direction of the vehicle 7.

When integration is performed using a computer, digital computer, etc., integration is used instead, so if equation (3) is expressed as integration every time the vehicle 7 moves by a small distance d, equation (4) is obtained.

Therefore, the current position Q (x, y) after traveling from any point P as a starting point is determined by the six values of x, y each time the vehicle 7 moves a small distance di after setting x=O2y=Q at point P. It is obtained by adding d-Ev/Q 'd-EU/6 Gyokuken-wo to each, and the travel trajectory is obtained by connecting any point (x, y) i from the starting point P to the current position Q. It is.

On the other hand, as described above, the traveling distance detector 1 generates a signal having a frequency proportional to the moving speed of the vehicle 7, but when this signal is converted into a pulse, a pulse is generated every time the vehicle 7 travels the above-mentioned fixed distance d. Each pulse is generated one by one - therefore, each time such a pulse is obtained from the mileage detector 1, the above-mentioned six values of
+ BV2- processing total control circuit 5 that adds each
By doing so, the travel trajectory and current position of the vehicle 7 can be easily calculated.

Next, the map memory 3 will be explained. FIG. 3 shows an example of a road map consisting of three main roads a, b, and c, but no matter how advanced semiconductor technology is, it is impractical to store all roads in the map memory 3. Therefore, if we limit it to only the main roads, it becomes possible to store the map as a two-dimensional figure as shown in Figure 3.Furthermore, as shown in Figure 4, by approximating the roads in a straight line, the amount of data can be significantly reduced. Therefore, it is even more advantageous in practical use. Generally, various data formats can be considered when storing map information in the map memory 3, but for example, when a road is approximated by a broken line as shown in FIG. 4, A1. Coordinates of At, As, A4, As (
Xtr ytL (Xtr y2) +---(Xll
+ys) may be stored in the map memory 3 as an appropriate binary number.

In addition, if the broken line approximation as shown in Fig. 3 is not used, each road can be divided into appropriate sections and the coordinates of both ends of each section can be stored in the map memory 3 in the same manner as described above. good.

Next, the marker moving device 6 will be explained. In FIG. 4, the mark ◎ indicated by M is an example of a current position marker, and the center point of the circle represents the current position Q of the vehicle 7. Above map memory 3
The map data is read out and the map is displayed on the display 4.] At this point, the current position marker M is placed approximately in the middle of the screen. Before moving the vehicle 7, it is necessary to move the current position marker M to the current position Q on the map. The means used for this purpose is the current position marker moving device 6.
It is. FIG. 5 shows a specific example of the marker moving device 6, and in the figure, the current position marker M is moved to the right, left, and top on the screen of the display 4 by operating switches 61, 62, 63, and 64. , is configured to be able to move independently in each direction below. For example, if the starting point is point B2 on the road in FIG. 4, operate the switch 62 to move the current position marker M to the left to M', then use the switch 64 to move the current position marker M downward. te B2
By matching the points, preparations for calculating and displaying the running trajectory using the B2 point as the starting point are completed.

Next, the specific operation of the present invention will be explained with reference to the displayed road map shown in FIG.

In the figure, the coordinates of each dot, ~D7, and the actual distance between each dot are stored in the map memory 3. S indicates a road that is a straight line approximation of the road S'. By the way, this invention is effective only when driving on the main roads that are stored in the map memory 3 in advance. In other words, starting from point B2,
When traveling on a road S' toward a point D1, let L be the actual distance of the road D1, and let L' be the value obtained by integrating the output signal of the distance detector 1 from the starting point D2 by the control circuit 5. , if the length of the road S on the display 4 screen is l, then B2
The current position marker M is displayed at a point moved by lx+ in the direction of point D4 from the point.

By the way, when a magnetic sensor is used as the azimuth detector 2, an incorrect azimuth may be indicated due to magnetic disturbances such as an oncoming vehicle or a railway bridge. On the other hand, since the travel distance detected by the travel distance detector 1 is relatively accurate, it is better to ignore the traveling direction of the vehicle 7 and display the current position using only the travel distance when traveling from point B2 to point B4. Good results are obtained.

If the above cumulative travel distance value L' becomes equal to L, the branch point D
4, and the direction detector 2 can detect whether the direction of travel of the vehicle 7 is D7 or D7.

FIG. 7 is a flowchart showing the operation of the control circuit 5, and shows a program consisting of seven steps from "Start" at Sl to "Stop" at 87. In this way, the operation of the control circuit 5 is executed by software processing of a microcomputer or the like.

As explained above, according to the present invention, a control circuit is provided for displaying the traveling locus or current position of a vehicle traveling on a road stored as information in a map memory, and a calculates the current position of the vehicle only from the mileage signal from the mileage detector, and detects the branching direction from the azimuth signal from the azimuth detector only at branch points, making it possible to display accurate vehicle travel information. It has a great effect.

[Brief explanation of drawings]

1 and 6 are block configuration diagrams showing one embodiment of the present invention, FIG. 2 is a principle explanatory diagram for explaining the principle of running trajectory calculation, and FIG. 3 is an explanatory diagram showing an example of a map. Figure 4,
FIG. 6 is an explanatory diagram showing an example of a straight road map;
FIG. 7 is a flowchart illustrating one embodiment of the present invention. 1... Mileage detector, 2... Direction detector, 3...
・Map memory, 4...Display device, 5...Control circuit, 6
...Current position marker moving device. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 7 Figure 2 Figure 3 Figure 4 (x+, vt) q+ t-, -, -1 Figure 5 Figure 7 1

Claims (2)

[Claims] (1) A mileage detector that detects the mileage of the vehicle, a direction detector that detects the direction of travel of the vehicle, a map memory that stores map information, a display having a two-dimensional screen, and the travel distance of the vehicle. a control circuit that calculates a travel distance signal obtained by the distance detector and an azimuth signal obtained by the azimuth detector and displays the traveling trajectory and current position of the vehicle on the display together with map information from the map memory; When the vehicle is traveling, between branch points on the road stored in the map memory, the current position of the vehicle is displayed on the display only from the mileage signal obtained from the mileage detector; A driving information display device 0 characterized in that at a road junction, a branch is detected using an azimuth signal obtained from the azimuth detector. (2) The driving information display device according to claim 1, wherein the current position of the vehicle is displayed by a movable marker on the display screen.