KR101211703B1 - Calibration method of the magnetometer error using a line of sight vector and the integrated navigation system using the same - Google Patents

Abstract

The present invention relates to a magnetic field correction method using a gaze vector and an integrated navigation system using the same. More specifically, an azimuth angle is estimated by using a known gaze vector value and measured values of a gaze vector, Magnetic field correction method using gaze vector to correct the magnetic field system and to apply the magnetic field correction method to the integrated navigation system to be applied to systems such as ships and aviation that require precise navigation. It relates to an integrated navigation system using the same.
The present invention relates to a magnetic field error correction method in a navigation system, comprising: a sensor error correction step for correcting an error generated in a magnetic sensor itself, an azimuth angle estimating step for estimating an azimuth angle of a body using a gaze vector, and the azimuth angle A magnetic field measurement step of measuring a magnetic field using the azimuth estimated in the estimating step, and a magnetic field error correction step of correcting an error of the magnetic field through an extended Kalman filter using data obtained in the azimuth estimating step and the magnetic field measuring step Characterized in that configured.

Description

Calibration method of the magnetometer error using a line of sight vector and the integrated navigation system using the same}

The present invention relates to a magnetic field error correction method using a gaze vector and an integrated navigation system using the same. More specifically, an azimuth angle is estimated using known gaze vector values and measured values of a gaze vector, and the estimated azimuth is used. Magnetic field error correction using gaze vector to correct the magnetic field system and to apply the magnetic field correction method to the integrated navigation system for ship, aviation, etc. systems that require precise navigation. The present invention relates to a method and an integrated navigation system using the same.

The use of drones is increasing in research in various fields, including the modern aviation industry. The drone is in the spotlight for its price / performance ratio compared to the manned aircraft and, above all, the great advantage of not having to guarantee the life of the pilot during the mission.

The most important thing in the operation and mission of the drone is the integrated navigation system because the performance of the integrated navigation system to ensure the stable flight of the drone, and further support the correct mission performance ability.

Most of the above navigation devices use an Inertial Navigation System (INS) based on an Inertial Measurement Unit (IMU) including an accelerometer and a gyro. Recently, a GPS (Global Positioning System) is used. It is also widely used to make it essential.

However, the IMU alone is difficult to measure in azimuth measurement, and there are various limitations in the navigation system including GPS, such as the use of GPS does not come out on the ground and stationary state, and it takes time until GPS satellites are caught. It is true.

INS is a self-contained navigation algorithm that can calculate continuous navigation information and has good dynamic characteristics, but has the disadvantage of accumulating errors over time due to the deflection error of the gyro and accelerometer.

The GPS / INS algorithm is a representative example of the integrated navigation algorithm to compensate for the shortcomings of the INS. The GPS / INS combining algorithm is excellent in the ability to correct the speed and position error of the INS based on the speed and position accuracy of the GPS.

However, when the GPS signal is disconnected due to external radio interference, the error of the navigation solution occurs as the filter algorithm does not normally estimate the error. In addition, GPS / INS coupling has a disadvantage in that posture error cannot be well compensated due to the inferior visibility of posture in the on-time state or the horizontal flight state.

In addition, in the past, a compass was used as a method for measuring azimuth, and this method is dependent entirely on the accuracy of the compass, and in the case of an analog compass, the accuracy is significantly lowered.

In the case of a digital compass, the accuracy of the azimuth measurement can be improved to some extent, but there is a problem that it is sensitive to electronic products that can distort magnetic fields, such as metal, iron, and magnets.

In addition, in the case of the navigation system used in the aircraft, if the flight control system, mission equipment, etc. are added or changed prior to the actual flight, the magnetic field is affected. Therefore, the error must be corrected again. A bidirectional calibration method was used to take two sensor readings and determine the effects from objects that distort the surrounding magnetic field.

However, the bidirectional adjustment method has a difficulty in measuring the value while rotating the whole system including the magnetic field by 180 degrees. In other words, since a person has to rotate the system directly, it takes a long time and there is a problem that an error in accuracy may occur.

The present invention has been made to solve the problems described above, an object of the present invention is to enable the estimation of the azimuth angle by using the eye gaze vector gaze vector capable of estimating an accurate azimuth angle independent of disturbance To provide a magnetic field error correction method using and an integrated navigation system using the same.

In addition, all magnetic fields must be additionally compensated for the Hard Iron Distortion error when used with other systems, such as those applied to navigation systems. The present invention eliminates the hassle of conventional bidirectional adjustment methods, To provide a magnetic field error correction method using a gaze vector and an integrated navigation system using the same to solve the difficulty of measuring by rotating the system 180 degrees when the system including the magnetic field is large and heavy, such as a ship's fuselage or a ship's hull. There is this.

In addition, the present invention configures an extended Kalman filter using a gaze vector to accurately estimate and correct an error of the magnetic field, and also requires precise navigation using the correction method of the magnetic field in an integrated navigation system. It is another object of the present invention to provide a magnetic field error correction method using gaze vectors and an integrated navigation system using the same, which can be applied to systems such as ships and aviation.

According to an aspect of the present invention,

A magnetic field error correction method in a navigation system, comprising: a sensor error correction step for correcting an error generated by a magnetic sensor itself, an azimuth angle estimating step of estimating an azimuth angle of a body using a gaze vector, and an azimuth angle estimating step A magnetic field measurement step of measuring a magnetic field using the estimated azimuth angle, and a magnetic field error correction step of correcting an error of the magnetic field through an extended Kalman filter using data obtained in the azimuth estimation step and the magnetic field measurement step. It features.

In this case, the azimuth estimating step may include a gaze vector measuring step of measuring a gaze vector at a body using an optical sensor, a position measuring step of measuring a current position of the body using a GPS, and a gaze measured at the gaze vector measuring step And an azimuth angle measuring step of measuring the azimuth angle of the body by comparing the vector with a gaze vector reference value at the position measured in the position measuring step.

식에 의해 방위각을 측정하는 것을 특징으로 한다.(이때,

: 동체(좌표계)에서 측정되는 시선벡터,

: 천문학 연감으로 부터 얻어지는 NED좌표계에서의 시선벡터,

,

: 오일러각으로 주어지는 좌표변환행렬,

: 롤각,

: 피치각,

: 방위각)In the azimuth measurement step,

It is characterized by measuring the azimuth angle by the equation.

: The eye vector measured in the body (coordinate system),

: The eye vector in the NED coordinate system obtained from the astronomical yearbook,

,

Is the coordinate transformation matrix given by Euler angle,

: Roll angle,

: Pitch angle,

Azimuth)

,

및 식에 의해 자기장을 측정하는 것을 특징으로 한다.(이때,

: 수평상태에서 동체좌표계 x축에서의 자기장 측정치,

: 수평상태에서 동체좌표계 y축에서의 자기장 측정치,

: 수평상태에서 동체좌표계 z축에서의 자기장 측정치,

: 자기장벡터의 크기,

: 해당 위도에서의 복각,

: 방위각,

: 자장계에서 측정된 자기장의 x축오차,

: 자장계에서 측정된 자기장의 y축오차,

: 자장계에서 측정된 자기장의 z축오차)In the magnetic field measuring step,

,

And The magnetic field is measured by an equation.

Is the magnetic field measurement in the x-axis of the fuselage coordinate system in the horizontal state,

= Magnetic field measurement in the y-axis of the fuselage coordinate system in the horizontal state,

: Magnetic field measurement in the z-axis of the fuselage coordinate system in the horizontal state,

Is the magnitude of the magnetic field vector,

: Dip at that latitude,

: Azimuth,

: X-axis error of the magnetic field measured in the magnetic field system,

: Y-axis error of the magnetic field measured in the magnetic field system,

Is the z-axis error of the magnetic field measured by the magnetic field

On the other hand, the integrated navigation system using the magnetic field error correction method according to the present invention,

In an integrated navigation system including an inertial navigation system (INS), an accelerometer, a gyroscope, a GPS, and a Kalman filter, a magnetic field error correction method using a gaze vector corresponding to any one of claims 1 to 4 is used. And a magnetic field correction filter unit configured to correct an error of the magnetic field system.

In this case, the magnetic field correction filter unit, a gaze vector sensor unit for estimating the azimuth angle of the body using a gaze vector, and a magnetic field and the gaze vector sensor unit for measuring a magnetic field using the azimuth angle estimated by the gaze vector sensor unit And an extended Kalman filter for correcting the error of the magnetic field using the magnetic field measured by the azimuth and magnetic field estimated at.

According to the present invention, it is possible to estimate the azimuth angle using the gaze vector, thereby having an excellent effect of estimating the precise azimuth angle regardless of disturbance caused by the magnetic field at low cost.

In addition, according to the present invention, by configuring an extended Kalman filter using the gaze vector as a state variable, it is possible to correct an error of the magnetic field system by a simple method, and precise navigation using such an error correction method in an integrated navigation system. It further has an effect that can be applied to systems such as ships, aviation, etc. that require.

In addition, according to the present invention, by simply adding a gaze vector sensor unit and a magnetic field correction filter unit including a magnetic field and an extended Kalman filter to an existing navigation system, the error of the magnetic field can be easily corrected. At the same time, when the magnetic field correction is performed, the initial magnetic field correction system can be selectively detached from the existing navigation system, which further has an effect that does not affect the increase of payload.

1 is a view showing a sun gaze vector in the NED coordinate system as an example of a gaze vector.
2 is a flowchart illustrating a method of correcting a magnetic field error using a gaze vector according to the present invention.
3 is a schematic representation of a conventional navigation system.
Figure 4 schematically shows an integrated navigation system according to the present invention.
5 is a graph showing the error of the magnetic field estimated by the magnetic field error correction method using a gaze vector according to the present invention.
6 is a graph illustrating azimuth errors when flying without correction of a magnetic field;
Figure 7 is a graph showing the azimuth error when flying after performing the magnetic field error correction according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the magnetic field error correction method using the gaze vector and the integrated navigation system using the same according to the present invention.

1 is a view showing a solar eye vector in an NED coordinate system as an example of a gaze vector, FIG. 2 is a flowchart illustrating a magnetic field error correction method using a gaze vector according to the present invention, and FIG. 3 is a schematic of a conventional navigation system. 4 is a diagram schematically showing an integrated navigation system according to the present invention, and FIG. 5 is a graph showing an error of a magnetic field estimated by a magnetic field error correction method using a gaze vector according to the present invention. 6 is a graph showing azimuth error when flying without correction of a magnetic field, and FIG. 7 is a graph showing azimuth error when flying after performing a magnetic field error correction according to the present invention.

The present invention makes it possible to estimate the azimuth angle using the known gaze vector value and the measurement value of the gaze vector, and to correct the magnetic field system using the estimated azimuth angle. This method relates to a magnetic field error correction method using a gaze vector and an integrated navigation system using the same, which can be applied to a system such as a ship or an aviation which requires precise navigation. The line of sight vector includes a line of sight vector 10, a line of sight vector, etc., and the line of sight vector used in the present invention also knows the line of sight vector 10, the line of sight vector and the exact position. A gaze vector looking at an object may be used, but the following description will be made based on an embodiment using the sun gaze vector 10. The.

That is, the sun gaze vector 10 refers to a gaze vector that looks at the sun as shown in FIG. 1, and based on the astronomical almanac, knowing the difference and time including the current exact latitude, longitude, and altitude. Since it is possible to know accurately, more accurate azimuth estimation and magnetic field correction is possible, so the sun gaze vector 10 is mainly utilized.

First, the magnetic field error correction method using the gaze vector according to the present invention includes a sensor error correction step (S10), azimuth estimation step (S20), magnetic field measurement step (S30) and magnetic field error correction step (S40) It is configured, the sensor error correction step (S10) is for correcting the error generated in the magnetic sensor itself mounted on the aircraft.

That is, since the strength of the earth's magnetic field is very small, such as 0.5 gauss, when measuring the earth's magnetic field with a magnetic sensor, it is necessary to take corrective actions in consideration of mounting errors and errors caused by the influence of surrounding objects. Alignment errors, Hard Iron Distortion, Soft Iron Distortion, and slope error.

In this case, the misalignment error refers to a case in which the external center line of the sensor and the measurement direction of the sensor do not exactly match when manufactured or mounted, and the Hard Iron Distortion distorts the magnetic field around the magnetic sensor when the magnetic material is positioned around the magnetic sensor. Due to this, the error of the periodic form occurs in the output value of the magnetic sensor, and the Soft Iron Distortion refers to the error that the period varies depending on the azimuth angle.

In addition, the tilt error refers to an error that occurs when the magnetic sensor is tilted in the pitch or roll direction, and corrects such misalignment errors, hard iron distortion, soft iron distortion, and tilt errors. Since the method is conventionally used, detailed description thereof will be omitted.

Next, if the flight control system, mission equipment, etc. is added or changed in advance of the actual flight, it will affect the magnetic field, which causes Hard Iron Distortion to require additional correction of the magnetic field system 120. In the present invention, instead of the conventional bidirectional calibration method, an error correction method comprising an azimuth estimation step S20, a magnetic field measurement step S30, and a magnetic field error correction step S40 is used.

Here, the azimuth angle estimating step (S20) is to estimate the azimuth angle of the fuselage such as an aircraft using the (sun) line of sight vector (10), the sun line vector measuring step (S22), the position measuring step (S24) and the azimuth angle measurement It comprises a step S26.

In more detail, the sun gaze vector measuring step S22 is a step of measuring the sun gaze vector 10 in a fuselage such as an aircraft using an optical sensor (not shown) such as a camera, and the position measuring step (S24). ) Relates to the step of measuring the current position of the body using a GPS (Global Positioning System) (50), the azimuth measurement step (S26) is a solar eye vector measured by an optical sensor such as a camera, astronomical yearbook It relates to the step of measuring the azimuth angle of the fuselage by comparing with the reference value of the sun gaze vector (10) at the location of the fuselage measured in the position measurement step based on.

At this time, in the azimuth measurement step (S26), the following equation is used for the measurement of the azimuth angle,

... (1)

... (One)

: 동체(좌표계)에서 측정되는 태양시선벡터,

: 천문학 연감으로부터 얻어지는 NED좌표계에서의 태양시선벡터(10),

,

: 오일러각으로 주어지는 좌표변환행렬,

: 롤각,

: 피치각,

: 방위각을 나타내는 것이다.here,

Is the solar eye vector measured in the body (coordinate system),

: Sun's line of sight vector (10) in the NED coordinate system obtained from the Astronomy Yearbook,

,

Is the coordinate transformation matrix given by Euler angle,

: Roll angle,

: Pitch angle,

: Indicates azimuth.

, 즉 동체에서 광학센서에 의해 측정된 태양시선벡터는 오일러각으로 주어지는 좌표변환행렬과, GPS(50)에 의해 측정된 현재위치에서의 천문학 연감으로부터 얻어지는 태양시선벡터(10)의 곱으로 표현될 수 있는데, 광학센서와 동체의 자세를 일치시킨 상태에서 태양시선벡터 측정단계(S22) 및 동체의 위치측정단계(S24)를 수행하면, 광학센서의 자세로부터 롤각(

)과 피치각(

)을 알 수 있으므로 상기 (1)식의 계산을 통해 동체의 방위각(

)을 측정할 수 있게 되는 것이다.That is, as shown in the above formula (1),

That is, the solar eye vector measured by the optical sensor in the fuselage is expressed as the product of the coordinate transformation matrix given by the Euler angle and the solar eye vector 10 obtained from the astronomical yearbook at the current position measured by the GPS 50. The solar eye vector measurement step (S22) and the position measurement step (S24) of the fuselage in a state where the posture of the optical sensor and the fuselage are matched may be performed.

) And pitch angle (

), So the azimuth angle of the body

) Can be measured.

Next, the magnetic field measuring step (S30) to measure the magnitude and direction of the magnetic field through the magnetic field system 120 using the azimuth angle estimated in the azimuth angle estimating step (S20) to correct the error of the magnetic field system 120 In relation to the above, in the magnetic field measuring step S30, the following equation representing a measurement value in a horizontal state of the magnetic field system 120 including an error of the magnetic field system 120 is used.

...(2),

...(2),

...(3),

... (3),

...(4)

...(4)

과,

및

는 각각 수평상태인 경우 동체좌표계의 x축, y축 및 z축에서의 자장계 측정치를 나타내고,

은 자기장벡터의 크기를 나타내며,

는 해당 위도, 즉 GPS(50)에 의해 측정된 위치에서의 복각(inclination)을 나타내고,

는 방위각 추정단계에서 구해진 방위각을 나타내며,

와

및

는 각각 Hard Iron Distortion을 포함하는 x축, y축 및 z축 오차를 나타낸다.At this time,

and,

And

Indicates the measurement of the magnetic field on the x-axis, y-axis, and z-axis of the fuselage coordinate system when each is horizontal.

Represents the magnitude of the magnetic field vector,

Represents the latitude, that is, the incidence at the position measured by the GPS 50,

Denotes the azimuth obtained from the azimuth estimation step,

Wow

And

Are the x-axis, y-axis, and z-axis errors, respectively, including Hard Iron Distortion.

That is, the intensity of the magnetic field measured by the magnetic field system 120 may be expressed as a sum of an error including a hard iron distortion and a value representing the magnitude and direction of the magnetic field as shown in Equation (2), (3), and (4). Will be.

Next, the magnetic field error correction step (S40), the magnetic field system 120 through the Extended Kalman Filter (130) using the data obtained in the azimuth estimation step (S20) and the magnetic field measurement step (S30) The step of correcting the error of, wherein, the state variables included in the extended Kalman filter 130 are as follows.

... (5)

... (5)

는 확장 칼만필터(130)의 상태변수이고,

및

은 자장계(120)에서 측정한 자기장 벡터의 크기 오차 및 그 미분값이며,

은 각각 롤링각, 피칭각 및 방위각으로 표현되는 동체의 자세 오차이고,

는 각각 자장계(120)에서 측정한 Hard Iron Distortion을 포함하는 자기장의 x축, y축 및 z축 오차를 나타내는 것이다.here,

Is the state variable of the extended Kalman filter 130,

And

Is the magnitude error of the magnetic field vector measured by the magnetic field system 120 and its derivative value,

Is the posture error of the fuselage represented by rolling angle, pitching angle and azimuth angle, respectively,

Represents the x-axis, y-axis, and z-axis errors of the magnetic field including the Hard Iron Distortion measured by the magnetic field system 120, respectively.

The system equation of the Extended Kalman Filter 130 having the state variable values as described above may be expressed as follows.

... (6)

... (6)

은 2×6의 영행렬을 의미한다.At this time,

Means 2 × 6 zero matrix.

)의 경우 위치에 따라서 변화하는 동특성이 있으므로 이를 1차 미분방정식으로 나타낼 수 있고, 나머지 자세오차(

)와, 자장계(120)에서 측정된 자기장의 오차(

)는 오차가 발산하지 않고 일정한 것이므로 모두 미분항이 0이 되기 때문이다.This is the magnitude error of the magnetic field vector (

) Can be represented as a first-order differential equation because there is a dynamic characteristic that varies with position.

) And the error of the magnetic field measured by the magnetic field system 120 (

) Is because the error term is constant and not constant, so the derivative term is all zero.

)를 추정할 수 있게 된다.The system equation of the extended Kalman filter 130 was obtained as shown in Equation (6) based on the dynamics of the actual model, and all the state variables as shown in Equation (5) were estimated. X, y, z axis error of magnetic field including Hard Iron Distortion measured at (120)

) Can be estimated.

)와 자장계(120)로부터 측정된 자기장의 오차(

)를 이용하여 다음과 같이 구성하였다.On the other hand, the measurement formula performed in the extended Kalman filter 130 is the measured value of the solar gaze vector (10) obtained in the above-described equations (1) and (2) (

) And the error of the magnetic field measured from the magnetic field system 120 (

) Was configured as follows.

..(7)

.. (7)

,

,

는 확장 칼만필터(130)의 측정치이고,

는 상기 식(5)에 나타낸 확장 칼만필터(130)의 상태변수이며,

는 노이즈를 포함한 일반적인 에러들을 포함하는 항이고,

은 에러를 포함하는 좌표변환행렬을 표현한 것이며, 나머지 변수들은 전술한 식(1) 내지 식(6)에서 설명한 바와 같다.here,

Is a measure of the Extended Kalman Filter 130,

Is a state variable of the Extended Kalman Filter 130 shown in Equation (5),

Is a term containing common errors including noise,

Denotes a coordinate transformation matrix including an error, and the remaining variables are as described in Equations (1) to (6).

In other words, the extended Kalman filter 130 receives the data measured from the azimuth estimation step S20 and the magnetic field measurement step S30, and calculates the system state variables shown in equation (5) at every step by the equation (7). Will be updated.

), 이의 미분값(

), 동체의 자세오차(

), 자기장의 x, y, z축 오차(

)를 추정하게 되고, 이로부터 자장계(120)의 추가적인 Hard Iron Distortion 오차를 추정하여 보정할 수 있게 되는 것이다.
Therefore, the extended Kalman filter 130 has a magnitude error of the magnetic field from the measured value of the solar gaze vector sensor unit 110 and the measured value of the magnetic field system 120 which will be described later.

), Its derivative (

), Posture error of the fuselage

), The x, y, and z axis errors of the magnetic field (

) And from this, additional hard iron distortion errors of the magnetic field system 120 can be estimated and corrected.

Meanwhile, the integrated navigation system according to the present invention includes a conventional navigation system including an inertial navigation system (INS) 20, an accelerometer 30, a gyroscope 40, a GPS 50, and a Kalman filter 60. It is characterized in that the magnetic field correction filter unit 100 for correcting the additional Hard Iron Distortion error of the magnetic field system 120 by applying the magnetic field error correction method using the above-described eye gaze vector, As described above, the conventional bidirectional adjustment method in which the entire system including the magnetic field system 120 is rotated by 180 degrees is improved to improve the error of the magnetic field system 120 by using a line of sight vector such as the solar line vector 10. It is to have the advantage that can be corrected more easily and precisely.

)와 상기 광학센서에 의해 측정된 태양시선벡터(

)의 비교를 통해 전술한 식(1)로부터 동체의 방위각(

)을 추정하는 역할을 하게 된다.In more detail, the magnetic field correction filter unit 100 includes a gaze vector sensor unit 110, a magnetic field system 120 and an extended Kalman filter 130, and the gaze vector sensor unit 110. Is composed of an optical sensor such as a camera, and serves to measure the sun's line of sight vector at the current position, and at the same time the NED coordinate system is based on the astronomical almanac from the current position of the fuselage measured by the GPS 50. Solar eye vector

) And the solar eye vector measured by the optical sensor

By comparing the azimuth angle of the fuselage (1)

) Will be estimated.

) 추정은 확장 칼만필터(130)에서 이루어지도록 구성할 수도 있다. 즉, 시선벡터 센서부(110)에서는 현재위치에서의 시선벡터를 측정하는 역할을 하고, 상기 확장 칼만필터(130)에서 GPS(50)를 통해 측정된 현재 동체의 위치로부터 천문학 연감에 근거하여 NED 좌표계에서의 태양시선벡터(

)와 상기 광학센서에 의해 측정된 태양시선벡터(

)의 비교를 통해 방위각(

)을 추정하게 되는 것이다.The azimuth angle of the fuselage using this line of sight vector (

) May be configured to be performed by the Extended Kalman Filter 130. That is, the gaze vector sensor unit 110 serves to measure the gaze vector at the current position, and the NED based on the astronomical yearbook from the current fuselage position measured by the GPS 50 in the extended Kalman filter 130. Sun line vector in coordinate system

) And the solar eye vector measured by the optical sensor

) To compare the azimuth (

) Is estimated.

)을 이용하여 Hard Iron Distortion 오차를 포함하는 자기장을 측정하는 역할을 하는 것이고, 상기 확장 칼만필터(130)는 태양시선벡터 센서부(110) 및 자장계(120)에서 얻어진 방위각(

) 및 자기장을 포함하는 데이터들을 이용하여 식(6) 및 식(7)에서 나타낸 바와 같이 자기장의 크기 오차(

), 이의 미분값(

), 동체의 자세오차(

), 자장계로부터 측정된 자기장의 x, y, z축 오차(

)를 추정하고, 이로부터 자장계(120)의 추가적인 Hard Iron Distortion 오차를 추정하여 보정하는 역할을 하는 것이다.In addition, the magnetic field system 120 has an azimuth angle estimated by the line of sight vector sensor 110 (

) To measure the magnetic field including the Hard Iron Distortion error, and the extended Kalman filter 130 is the azimuth angle obtained from the solar gaze vector sensor unit 110 and the magnetic field system (120).

) And the magnitude error of the magnetic field as shown in equations (6) and (7) using data including

), Its derivative (

), Posture error of the fuselage

), The x, y, and z axis errors of the magnetic field measured from the

) To estimate and correct additional Hard Iron Distortion errors of the magnetic field system 120.

At this time, the magnetic field correction filter unit 100 configured as described above is used in addition to the existing navigation system selectively only in the case of additional hard iron distortion error correction of the magnetic field system 120, and after the error correction is completed from the navigation system Of course, it can be configured so as not to affect the increase of payload that greatly affects the performance of the aircraft and the like.

정도의 Hard Iron Distortion 오차와 가속도계(30)의 편향오차 및 노이즈를 고려하였다. On the other hand, Figures 5 to 7 shows the results of the two-dimensional simulation for verifying the performance of the magnetic field error correction method using the gaze vector and the integrated navigation system using the same, the magnetic field system 120 as a simulation condition )of

The degree of Hard Iron Distortion error and the deflection error and noise of the accelerometer 30 are considered.

First, FIG. 5 shows a simulation result of the error estimated by the magnetic field correction filter unit 100. Although some errors remain due to the error and noise of the accelerometer 30, the error is relatively uniform at about 0.05 gauss. It can be confirmed that it is estimated.

6 and 7 do not correct the error of the magnetic field system 120 through simulation in order to check the effect of the error correction of the magnetic field system 120 by the magnetic field correction filter unit 100 (FIG. 6). ) And the case of error correction (FIG. 7), and the simulation was set to a situation where the azimuth was kept constant at 30 ° after the azimuth was changed from 0 ° to 30 °.

As can be seen in FIG. 6, when the error correction of the magnetic field system 120 is not performed, the azimuth angle may be about 17 degrees or more due to Hard Iron Distortion, and the error correction of the magnetic field system 120 may be performed. In this case, as shown in FIG. 7, it was confirmed that the azimuth was relatively accurately estimated.

Therefore, according to the magnetic field error correction method using the gaze vector and the integrated navigation system using the same according to the present invention as described above, it is possible to estimate the azimuth angle using the gaze vector, so that it is accurate regardless of disturbance caused by the magnetic field at low cost. It is only possible to estimate the azimuth angle and to add the field vector correction unit 110, the magnetic field correction filter unit 100 including the magnetic field system 120 and the extended Kalman filter 130 to the existing navigation system. In addition, it is possible to simply correct the error of the magnetic field system 120, and at the same time the magnetic field initial correction unit 100 can be selectively detached to the existing navigation system at the time of correction of the magnetic field to increase the payload Not only does it affect the system of ships, aviation, etc. that require precise navigation by using the error correction method of the magnetic field system 120 in the integrated navigation system It will have various advantages such as being applicable.

Although the above embodiments have been described with respect to the most preferred examples of the present invention, it is not limited to the above embodiments, and it will be apparent to those skilled in the art that various modifications are possible without departing from the technical spirit of the present invention.

The present invention relates to a magnetic field error correction method using a gaze vector and an integrated navigation system using the same. More specifically, an azimuth angle is estimated using known gaze vector values and measured values of a gaze vector, and the estimated azimuth is used. Magnetic field error correction using gaze vector to correct the magnetic field system and to apply the magnetic field correction method to the integrated navigation system for ship, aviation, etc. systems that require precise navigation. The present invention relates to a method and an integrated navigation system using the same.

10: solar eye vector 20: inertial navigation system
30 accelerometer 40 gyroscope
50: GPS 60: Kalman Filter
100: magnetic field correction filter unit 110: gaze vector sensor unit
120: magnetic field system 130: extended Kalman filter

Claims (6)

In the magnetic field error correction method in the navigation system,
Sensor error correction step for correcting the error generated in the magnetic sensor itself,
An azimuth angle estimating step of estimating the azimuth angle of the body using a line of sight vector;
A magnetic field measuring step of measuring a magnetic field using the azimuth angle estimated in the azimuth estimating step;
And a magnetic field error correcting step of correcting an error of the magnetic field through an extended Kalman filter using data obtained in the azimuth estimating step and the magnetic field measuring step.
The method of claim 1,
The azimuth estimation step,
A gaze vector measurement step of measuring a gaze vector in a fuselage using an optical sensor;
Position measuring step of measuring the current position of the fuselage using GPS and
Using the gaze vector, characterized in that it comprises an azimuth measurement step of measuring the azimuth angle of the body by comparing the gaze vector measured in the gaze vector measurement step and the gaze vector reference value at the position measured in the position measuring step. Magnetic field correction method.
The method of claim 2,
In the azimuth measurement step,

Magnetic field correction method using a gaze vector, characterized in that for measuring the azimuth angle by the equation.
(At this time,

: The eye vector measured in the body (coordinate system),

: The eye vector in the NED coordinate system obtained from the astronomical yearbook,

,

Is the coordinate transformation matrix given by Euler angle,

: Roll angle,

: Pitch angle,

Azimuth)
The method of claim 1,
In the magnetic field measuring step,

,

And

Magnetic field correction method using a gaze vector, characterized in that for measuring the magnetic field by the equation.
(At this time,

Is the magnetic field measurement in the x-axis of the fuselage coordinate system in the horizontal state,

= Magnetic field measurement in the y-axis of the fuselage coordinate system in the horizontal state,

: Magnetic field measurement in the z-axis of the fuselage coordinate system in the horizontal state,

Is the magnitude of the magnetic field vector,

: Dip at that latitude,

: Azimuth,

: X-axis error of the magnetic field measured in the magnetic field system,

: Y-axis error of the magnetic field measured in the magnetic field system,

Is the z-axis error of the magnetic field measured by the magnetic field
In an integrated navigation system including an inertial navigation system (INS), an accelerometer, a gyroscope, a GPS and a Kalman filter,
An integrated navigation system comprising: a magnetic field correction filter unit configured to correct an error of the magnetic field system by using a magnetic field error correction method using a gaze vector corresponding to any one of claims 1 to 4 system.
6. The method of claim 5,
The magnetic field correction filter unit,
A gaze vector sensor unit for estimating the azimuth angle of the body using a gaze vector;
A magnetic field measuring magnetic field using the azimuth angle estimated by the eye vector sensor unit;
And an extended Kalman filter configured to correct an error of the magnetic field by using the magnetic field measured by the azimuth angle and the magnetic field estimated by the eye vector sensor unit.

Images