JPH0640009B2 - Course guidance device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on a current position information obtained based on the outputs of a course guidance device, particularly a magnetic direction sensor for detecting a geomagnetic direction and a distance sensor for detecting a traveling distance. In the course guiding device for guiding the course of the moving body, the deviation of the magnetic azimuth sensor generated when the moving body is running is corrected based on the current position information to accurately guide the running course. The present invention relates to a course guidance device that is designed to be performed.

Conventionally, it has been considered to detect the azimuth in the traveling direction of the moving body by detecting the geomagnetic azimuth using a magnetic azimuth sensor that detects the direction of the magnetic field. Then, the current position of the passenger car is extracted based on the outputs of the magnetic direction sensor and the distance sensor mounted on a moving body such as a passenger car, and the traveling direction at a predetermined point on the traveling course is displayed on the display, for example. That is, a course guiding device for a moving body is being developed which provides a left turn, a right turn, and a direction for going straight, and guides a traveling course according to a guidance about a destination approach or the like by voice guidance.

The principle of azimuth detection by the magnetic azimuth sensor in the course guidance device will be described with reference to FIG. Reference numeral 1 in the figure is a magnetic azimuth sensor, and by detecting the geomagnetism in two orthogonal X and Y axis directions, for example, as shown in FIG. Sensor 1
The angle θ in the Y direction can be obtained. That is, the outputs (V _x , V) of the magnetic direction sensor 1 in the X-axis and Y-axis directions.
_y ) is represented by the following equation (1).

If the X-axis and Y-axis sensitivities of the magnetic azimuth sensor 1 are adjusted to be uniform, that is, K _x = K _y = K, the magnetic azimuth sensor is calculated based on the equation (1). The angle θ of 1 with respect to the magnetic north direction in the Y direction can be obtained by the following equation (2).

In this way, the traveling direction of the moving body can be known from the output of the magnetic direction sensor 1. However,
When the magnetic direction sensor 1 is mounted in a vehicle constituted by an iron plate such as a passenger car, the output of the magnetic direction sensor is offset due to the influence of the magnetization of the iron plate constituting the vehicle. As a result, it is not possible to detect the exact direction of the geomagnetism. Further, the detection sensitivity may vary depending on the mounting position of the magnetic direction sensor in the vehicle. Therefore, from such a fact, if the output of the magnetic direction sensor is simply used as it is as data for determining the direction of the traveling direction, there is a problem that an error occurs in the current position display.

In order to solve the above problems, the applicants of the present application add corrections such as offset correction and sensitivity correction to the output of the magnetic azimuth sensor prior to the application of the present application. It has been proposed to provide a course guidance device as shown in FIG. 2 equipped with a magnetic azimuth detection device for accurately detecting the direction. In the figure, 1 is a magnetic direction sensor, 2 is A
/ D converter, 3 is an initial correction unit, 4 is an angle conversion unit, 5
Is a unit vector generator, 6 is a distance sensor, 7 is an integrator,
Reference numeral 8 represents a current position memory, and 9 represents a display unit.

In FIG. 2, outputs V _x , V of the magnetic azimuth sensor 1
_y (the analog signal represented by the equation (1)) is
It is converted into a digital signal by the A / D converter 2. The initial correction unit 3 performs offset correction and sensitivity correction in the initial state on the outputs V _x and V _y of the magnetic direction sensor 1 converted into digital signals by the A / D converter 2. The initial correction in the initial correction unit 3 is performed based on the equation (3).

Next, in the angle conversion unit 4, the traveling azimuth θ is obtained from the output of the initial correction unit 3, that is, the corrected outputs V ′ _x and V ′ _y of the magnetic azimuth sensor 1. The traveling azimuth θ is
It is calculated by (4).

^{θ = tan -1 (V 'x} / V' y) ........................... (4) unit vector generating section 5, the angle conversion unit output or the (4) of the 4 by connexion shown in equation The sin and cos components of the running azimuth angle θ, that is, sin θ and cos θ are obtained. In addition, the distance sensor 6 corresponds to the rotation of the wheels, for example, by a constant distance Δ.
A clock pulse is output each time the vehicle runs. And
In the integrator 7, the distance sensor 6
Each time a pulse is input, that is, every time the mobile body travels a distance Δl, the traveling azimuth information input from the unit vector generation unit 5, that is, the sin θ and cos θ are sequentially integrated,
The integrated value is sequentially stored in the current position memory 8 as current position information of the moving body. The current position information stored in the current position memory 8 is as shown in FIG.
The current position information (X _i , Y _i ) corresponding to the traveling position P _i is the coordinate value of the traveling position P ₁ , P ₂ , ..., P _n for each distance Δl. Represented.

Then, based on the contents of the current position memory 8, an indication of the traveling direction corresponding to the current position of the moving body, that is, the position for each traveling distance Δl is displayed on the display unit 9. Display 9
Is a display device constituted by a CRT or LCD, for example.

In the course guidance apparatus described above, the accuracy of the output of the magnetic azimuth sensor 1 in the initial correction unit 3, especially the suitability of the declination correction, greatly affects the accuracy of the current position display.
This will be specifically described with reference to FIGS. 4 and 5. In FIG. 4, ▲ ▼ shows an output vector (represented by a unit vector whose size is 1) of the magnetic direction sensor 1 when there is no declination. However, the fourth
As shown in the figure, for example, when there is a declination α in the azimuth “west” direction, the output of the magnetic azimuth sensor 1 is obtained by combining the azimuth θ and the declination α. Since the detected azimuth angle θ changes to θ ′, an error occurs in the current position information stored in the current position memory 8. Therefore, for example, the current position information when going straight in the azimuth θ direction is the fifth position information.
It should be on the locus l ₁ continuing with P ₁ , P ₂ and P ₃ shown in the figure, but stored in the current position memory 8 as being on the locus l ₂ following P ′ ₁ , P ′ ₂ and P ′ _3. . That is, as described above, in the example shown in FIG. 2, there is a drawback that an error occurs in the current position information because the deviation angle error is not corrected.

The present invention aims to solve the above drawbacks,
By correcting the error in the output of the magnetic azimuth sensor due to the declination of the geomagnetism based on the current position information of the moving body obtained by the traveling of the moving body, it is possible to always obtain accurate current position information. ， The purpose is to provide a course guidance device that enables effective course guidance. Hereinafter, description will be given with reference to the drawings.

FIG. 6 is a block diagram showing the basic construction of an embodiment of the present invention. Reference numerals 1 to 9 in the figure correspond to those in FIG. 2, 10 is an input unit for inputting positional information of a predetermined point read from a map or the like, 11 is a declination correction value calculation A part for calculating the declination correction value by comparing the position information input from the input part 10 with the contents of the current position memory 8, and 12 is a declination correction value memory for the declination correction. A declination correction value calculated by the value calculation unit 11 is stored, 13 is a declination correction unit, and the angle conversion unit 4 is based on the declination correction value stored in the declination correction value memory 12. Represents the one for performing declination correction for the azimuth angle calculated in.

The operation of the magnetic azimuth sensor 1 or the display unit 9 in the embodiment shown in FIG. 6 is the same as that of the conventional example shown in FIG. 2 described at the beginning of the present specification. However, in the present invention,
A declination correction unit 13 is provided for performing declination correction processing on the output of the angle conversion unit 4 based on the contents of a declination correction value memory 12 to be described later, and the initial correction unit 3 performs offset correction and sensitivity correction. With respect to the output of the magnetic azimuth sensor 1 that has been subjected to the correction processing, the declination correction unit 13 is further added.
Is used to correct the declination so that accurate current position information can be obtained. The correction processing in the deviation angle correction unit 13 is performed based on the deviation angle correction value stored in advance in the deviation angle correction value memory 12. The deviation angle correction value is calculated in the deviation angle correction value calculation unit 11 by the following calculation processing.

That is, the true coordinate data (where the starting point is the coordinate origin) of the point when the moving body is run for a predetermined distance is read out on the map, and the declination correction value calculation section is input via the input section 10. Enter in 11. On the other hand, when the magnetic azimuth sensor 1 includes a deviation angle error, the current position information stored in the current position memory 8 at that time point includes the deviation angle error. For example, the declination correction value memory 1
This is because the declination correction value has not been set in No. 2, so that the declination correction in the declination correction unit 13 has not been performed. Therefore, the declination correction value calculation unit 11 compares the contents of the current position memory 8 with the coordinate data input from the input unit 10. When the error of this comparison result is measured, the deviation angle α can be determined as is known from the error and the distance from the coordinate origin to the true coordinate data input point. It can be calculated. Then, the deviation angle correction value is stored in the deviation angle correction value memory 12.

In this way, after the deviation angle correction value is stored in the deviation angle correction value memory 12, the deviation angle correction processing in the deviation angle correction unit 13 is performed based on the deviation angle correction value, After that, the current position information stored in the current position memory 8 becomes accurate.

As described above, according to the present invention, since the input section is provided to correct the declination amount of the geomagnetism included in the magnetic direction sensor, accurate position information at a predetermined point and the point can be obtained. By calculating the declination correction value by comparing and calculating the contents of the present position memory at, the declination correction is performed using this declination correction value, so that accurate current position information can always be obtained. It is possible and effective course guidance can be performed.

[Brief description of drawings]

FIG. 1 is an explanatory view of a magnetic orientation sensor used in a course guiding device, FIG. 2 is a block diagram showing a configuration of a conventional example of the course guiding device, and FIG. 3 is a description of a mode of current position information in the course guiding device. Explanatory drawing for, FIG. 4 and FIG.
FIG. 6 is an explanatory diagram for explaining a deviation angle error included in the output of the magnetic direction sensor, and FIG. 6 is a block diagram showing the configuration of an embodiment of the course guiding device of the present invention. In the figure, 1 is a magnetic direction sensor, 2 is an A / D converter, and 3
Is an initial correction unit, 4 is an angle conversion unit, 5 is a unit vector generation unit, 6 is a distance sensor, 7 is an integrator, 8 is a current position memory, 9 is a display unit, 10 is an input unit, and 11 is a declination correction value. An arithmetic unit, 12 is a declination correction value memory, and 13 is a declination correction unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinari Hara 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd. (56) Reference JP-A-58-70317 (JP, A)

Claims (1)

[Claims] 1. A magnetic azimuth sensor for detecting geomagnetic azimuth to output traveling direction information of a moving body, and a distance sensor for outputting traveling distance information of the moving body, and outputs of the magnetic azimuth sensor and the distance sensor. The vehicle is equipped with a current position memory that stores the current position information of the moving body calculated based on the above, and travels based on the map mounted on the vehicle and displayable on the vehicle and the contents of the current position memory. In a course guiding device for guiding a course, an input unit for inputting arbitrary predetermined coordinate data at a time point after the moving body has traveled, the coordinate data input from the input unit, and the current A declination correction value calculation unit for calculating a declination correction value based on the calculated position information at a time point after the moving body travels stored in the position memory, and the declination angle. Course guidance device which on the basis of the declination correction value calculated from the positive arithmetic unit, characterized by comprising a polarization angle correction unit that performs declination correction to the output of the magnetic direction sensor.