KR19980051744A - A method for correcting the position error of the electronic azimuth sensor - Google Patents

Abstract

The present invention relates to an electronic orientation sensor, and more particularly, to an electronic orientation sensor capable of correcting a position detection error caused by an electromagnetism system when an electronic orientation sensor is mounted on a vehicle And a position error correction method.

To this end, the present invention provides an electronic orientation sensor mounted on a moving object and detecting the moving direction of the moving object in accordance with a change in output of the X, Y coils due to geomagnetism, Receiving the output of the X and Y coils of the electronic azimuth sensor by geomagnetism detection at a plurality of predefined measurement points (n) and storing them as Xn, Yn, and outputting an output value Xn Yn, and Yn based on the output values Xn, Yn and the center coordinate values at the respective measurement points, calculating central coordinate values Cx, Cy based on the maximum value and the minimum value of the respective output values, calculating a ratio dYn / dXn of the calculated two values; calculating a ratio dYn / dXn between the calculated two values based on the calculation result; And calculating a value beta.

Description

A method for correcting the position error of the electronic azimuth sensor

The present invention relates to an electronic orientation sensor, and more particularly, to an electronic orientation sensor capable of correcting a position detection error caused by an electromagnetism system when an electronic orientation sensor is mounted on a vehicle And a position error correction method.

In general, a radio navigation system used in an aircraft, a ship, etc. receives a radio wave from two or more radio wave sources and obtains the current position by obtaining the distance from the radio wave source by the arrival time difference and phase difference of the radio wave, I was able to sail the ocean safely. Therefore, in recent years, navigation systems for automobiles have been rapidly developed and are being widely used so that a car having the same movement can be judged as to where on the map it is currently traveling.

The car navigation system (CNS) reads the road map data stored in the CD-ROM database on the CRT screen installed in the center of the front seat of the vehicle, The most important issue is to understand the current bearing of the car.

Therefore, in the navigation system for a car (CNS), various sensors are mounted on a vehicle to detect a traveling direction. One of them is a geomagnetic sensor, which is a ring-shaped permalloy magnetic body, And an excitation coil 2 wound around the outer periphery of the core 1 and an X coil 3 and a Y coil 4 serving as detection coils are wound orthogonally to each other in the radial direction of the core 1 .

2 (A), when an AC current is passed through the exciting coil 2 to excite it, a magnetic force line as indicated by the arrow in FIG. 2 (a) And the core 1 is ring-shaped, so that the stimulation is impossible. Since the electromotive force is generated in accordance with the changes of the magnetic fluxes in the X and Y coils 3 and 3 and 4 of the Y coil 4, the magnetic force lines in the directions 1 and 2, 3 and 4 are opposite to each other, And the output of the Y coil 4 are eliminated. When a magnetic field is applied from the outside in a direction parallel to the Y coil 4, a maximum voltage is generated in the X coil 3, and when an external magnetic field is generated as shown by a single point arrow in the 45 ° direction as shown in FIG. A 1/2 peak voltage is generated in the X coil 3 and the Y coil 4, respectively.

The direction of the geomagnetism to the vehicle body can be detected by measuring the magnitude of the output voltage of the X coil 3 and the Y coil 4 by installing the X coil 3 in the front and rear direction of the vehicle body in the center of the loop, By detecting the direction of the geomagnetism, the traveling direction of the vehicle can be detected.

However, in such a conventional electronic bearing sensor, for example, the geomagnetic sensor is installed in the center of the loop, which is difficult to be influenced by magnetic force from the residual magnetism and the automobile electric component possessed by the iron plate itself of the vehicle body. However, the magnetic field caused by the geomagnetism is very weak, There is a problem that an error is likely to occur.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide an electronic orientation sensor capable of detecting the net magnetic field by eliminating the influence of the magnetized magnetic field around the electronic orientation sensor. And to provide a position error correction method.

1 is a perspective view showing a configuration of a general geomagnetic sensor,

2 (a) and 2 (b) are diagrams for explaining the operation of the geomagnetic sensor shown in FIG. 1,

FIG. 3 is a graph showing the respective outputs of the geomagnetic sensor shown in FIG. 1,

Fig. 4 is a view for explaining a position error due to an magnetizing field of a geomagnetic sensor,

5 is a flowchart for explaining a position error correction method of the electronic azimuth sensor according to the present invention,

6 is a view for explaining a position error correction method of an electronic orientation sensor according to the present invention,

7A and 7B are tables and graphs for explaining the correction angle calculating method according to an embodiment of the present invention.

Description of the Related Art [0002]

1 .. core, 2 ... excitation coil,

3 ... X coils, 4 ... Y coils,

In order to achieve the above object, an electronic orientation sensor for detecting a moving direction of a moving object in accordance with a change in output of an X, Y coil by a geomagnetism mounted on a moving object, And outputs the outputs of the X and Y coils of the electronic azimuth sensor by geomagnetism detection at a plurality of preset measurement points n and stores them as Xn and Yn in a state in which the longitudinal direction of the moving body coincides with the north- Calculating a maximum value and a minimum value of the output values Xn and Yn of the electronic orientation sensor sensed at the respective measurement points and calculating center coordinate values Cx and Cy based on the maximum value and the minimum value of each output value; Calculating dXn and dYn on the basis of the output values Xn and Yn and the center coordinate value of the sensor, calculating the ratio dYn / dXn of the two calculated values, And calculating a correction value beta for correcting an error of the moving direction measurement of the moving object by the moving object.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a configuration and operation effects according to preferred embodiments of the present invention will be described in detail.

First, as shown in Fig. 1, an electromagnetic orientation sensor generally comprises a core 1 as a ring-shaped permalloy magnetic body, an excitation coil 2 wound around the outer periphery of the core 1, and an X coil 3 and the Y coils 4 are wound perpendicularly to each other in the radial direction of the core 1.

When the electronic orientation sensor having such a configuration is rotated 360 degrees relative to the magnetic base in a state of being mounted on the vehicle, the Y output is represented by the waveform of the sine function and the X output has a phase difference of 90 degrees from the Y output cosine function. Therefore, when the X and Y components are squared and summed, the original function is established. That is, as shown in FIG. 4, in the case of an ideal X, Y output in which only a pure geomagnetism is detected without being influenced by an external magnetic field, a circle having a radius R is obtained. However, in reality, the center of the circle is shifted to an ellipse having a major axis and a minor axis due to the magnetization system around the sensor. Therefore, a correction method for correcting the error by the movement amount of the center point of the circle is needed.

As shown in the flowchart of FIG. 5, in the method for correcting the position error of the electronic azimuth sensor according to the present invention for correcting the position error, in step S10, Direction, the step S12 rotates the vehicle by 360 degrees and simultaneously operates the electronic orientation sensor. Accordingly, in step S14, the X and Y output values detected by the electronic orientation sensor are changed at the same time as the vehicle is rotated. At this time, when the vehicle is rotated by 45 degrees, i.e., 0, 45, 90, 135, 180 °, ..., 270 °, and 315 °, the X and Y output values of the electronic azimuth sensor at each measurement point are stored.

In step S16, if the vehicle is rotated 360 degrees and the X and Y outputs at the eight measurement points are detected, the process proceeds to step S18, where the X and Y output values measured at the respective measurement points are compared to calculate the maximum value and the minimum value . In step S20, the center coordinate value is calculated on the basis of the maximum value and the minimum value of the X and Y outputs thus calculated. This is calculated by Cx = (Xmax + Xmin) / 2 and Cy = (Ymax + Ymin) / 2 (See Fig. 6).

Further, the step (S22) is calculated in the dX, dy mm and _n for each of the X, Y output value sensed from eight each measurement point in accordance with the vehicle rotated 360 ° Sikkim. In other words, dx ₀ = xo-Cx, dy ₀ = Yo-Cy and mm ₀ = dy ₀ / dx ₀ at 0 ° are calculated, and dx, dy and mm _n are calculated at the other seven measurement points by the same method do.

Based on the thus calculated mm _n value, the ratio of each of the eight directions (0, 45, 90, 135, 180, 225, 270, 315 degrees) is calculated and the trajectory of each measurement point with respect to the center point is drawn. to be displayed as a curve, which is a graph obtained on the assumption in 7 (a) the value of _n mm at each measurement point as a example.

At this time, in step S24, the sign of the obtained mm value changes from (+) to (-), and when the change amount is? 0, an angle? (Here,? = Tan ^-1 , the correction angle beta is calculated on the basis of the measurement point at which the sign of the mm value is changed. That is, the correction angle β = tan ^-1 (mm) is calculated by the equation _DEG - Ψ. In this case, Ψ represents the azimuth at the point of measurement where the mm value is changed, and Ψ = measurement point (n) * 45. That is, in the embodiment shown in FIG. 6, since the measurement point where the sign of the mm value changes from (+) to (-) is a measurement point having an angle of 180 °, the correction angle β = tan ^-1 (mm) _DEG - ^-1 (-2.412) _DEG -180 = -67.48-180 = -247.5 DEG.

When the correction angle beta is obtained, dX '= X'-Cx, dY' = (X ', Y') for the X and Y output values X 'and Y' detected by the electronic orientation sensor in a situation where the vehicle is traveling on an actual road, Y'-Cy is calculated to obtain the traveling direction (? ') Of the vehicle, and then the position error of the correction angle (?) Is corrected. That is, the traveling direction? 'Of the vehicle detected by the electronic orientation sensor is calculated by tan ^-1 (dX' / dY '), and the correction angle (?') Calculated by the position error correction method according to the present invention β) during traveling and a is the direction of the deviation to calculate the direction of the position error is corrected by the predetermined correction position deviation detection operation, a case where the correction operation is ^{θ = tan -1 (dX '/} dY ') -?, whereby it is possible to determine the traveling direction? of the accurate car.

As described above, according to the position error correction method of the electronic azimuth sensor according to the present invention, the position error due to the influence of the magnetized magnetic field around the sensor mounted in the traveling direction of the self- So that it is possible to determine the accurate traveling direction of the vehicle by only the pure geomagnetism.

Claims (6)

An electronic orientation sensor mounted on a moving object for detecting a moving direction of the moving object in accordance with a change in output of X, Y coils due to geomagnetism, And outputs the outputs of the X and Y coils of the electronic azimuth sensor by geomagnetism detection at a plurality of preset measurement points n and stores them as Xn and Yn in a state in which the longitudinal direction of the moving body coincides with the north- step, Calculating a maximum value and a minimum value of the output values Xn and Yn of the electronic azimuth sensor sensed at the respective measurement points and calculating center coordinate values Cx and Cy based on the maximum value and the minimum value of each output value, Calculating dXn and dYn based on the output values Xn and Yn and the central coordinate values at the respective measurement points and calculating a ratio dYn / dXn of the two calculated values; And calculating a correction value (?) For correcting an error of the traveling direction measurement of the moving body by the magnetization system around the sensor based on the calculation result. 2. The position error correction method according to claim 1, wherein the center coordinate values Cx and Cy are calculated by Cx = (Xmax + Xmin) / 2 and Cy = (Ymax + Ymin) / 2 . 3. The method of claim 2, wherein dXn and dYn are calculated by dXn = Xn-Cx and dYn = Yn-Cy, respectively. 2. The method according to claim 1, wherein the correction value calculation step calculates the measurement point when the value of dYn / dXn changes from positive to negative and the traveling direction of the moving object at the measurement point, Of the position error is calculated by subtracting the correction value (?) Of the position error from the position error correction value (?). The method of claim 4, wherein the moving direction of the moving object is calculated by tan ^-1 (dYn / dXn). The method of claim 1, wherein the predetermined plurality of measurement directions represent eight orientations.