Airborne magnetic heading sensor high environment adaptability calibration method and device

Abstract

The invention discloses an airborne magnetic heading sensor high environmental adaptability calibration method and device, which uses aircraft inherent magnetic field environmental parameters to replace original non-magnetic laboratory reference parameters, improves and adds a mode of manually selecting sampling points in an eight-point calibration process at the same time, can enhance the environmental adaptability of magnetic heading calibration, and is verified by practical application. Therefore, the calibration technology can eliminate the influence of the inherent magnetic interference of the environment and the shaking of the calibration point on the calibration environment interference level at the same time, improves the environmental adaptability of the calibration of the magnetic heading sensor, and can realize the calibration of the magnetic heading sensor in the environment with non-uniform rotation, environmental disturbance and magnetic interference.

Description

Technical Field

[0001] The invention belongs to the technical field of airborne magnetic heading sensor calibration, and relates to a method and a device for calibrating an airborne magnetic heading sensor with high environmental adaptability. Background Art

[0002] The magnetic heading sensor is a magnetoresistive magnetic sensor. Its working principle is the magnetoresistive effect. It measures the magnetic field by measuring the influence of the magnetic field on the magnetoresistor. When the external magnetic field and the direction of the built-in magnetic field of the magnet are at a zero degree angle, the resistance will not change with the change of the external magnetic field; when the external magnetic field and the built-in magnetic field of the magnet have a certain angle, the magnetization vector inside the magnet will shift and the film resistance will decrease. This characteristic is called the anisotropic magnetoresistance effect. See attached Figure 1 .

[0003] The resistance value of the thin film alloy will change with the external magnetic field angle. The resistance and magnetic field characteristics are nonlinear, and each resistor does not correspond to a unique external magnetic field value. Figure 1 It can be seen that when the current direction is parallel to the magnetization direction, the sensor is most sensitive. When the current direction and the magnetization direction form an angle of 45°, the magnetic resistance works near the linear region, so that the linear characteristics of the output can be achieved.

[0004] The basic structure of the magnetoresistive magnetic sensor consists of four magnetoresistors forming a Wheatstone bridge. The power supply is Vb, and the current flows through the resistors. When a bias magnetic field H is applied to the bridge, the magnetization direction of the two oppositely placed resistors will rotate in the direction of the current, and the resistance of the two resistors will increase; while the magnetization direction of the other two oppositely placed resistors will rotate in the opposite direction of the current, and the resistance of the two resistors will decrease. By measuring the voltage difference between the two output terminals of the bridge, the external magnetic field data can be obtained.

[0005] According to the above principle, if there is a fixed interfering magnetic field superimposed on the bias magnetic field during the calibration of the magnetic heading sensor, the magnetic field data finally measured will include the inherent magnetic field of the carrier and the earth's magnetic field data. At the same time, the shaking during the calibration process will cause the external magnetic field angle to change, which in turn causes the magnetic resistance value of the Wheatstone bridge to change, resulting in errors in the magnetic field data measurement. The size of the error is positively correlated with the degree of shaking.

[0006] When the aircraft magnetic heading sensor is calibrated at eight points, the power supply vehicle usually supplies power to the aircraft, while the tractor tows the aircraft in a circular motion, and starts and stops manually. The calibration process is subject to magnetic interference, non-uniform speed of the tractor, and shaking interference caused by starting and stopping, which have a significant impact on the results of the magnetic heading calibration. Summary of the invention

[0007] The present invention provides a calibration method for an airborne magnetic heading sensor with high environmental adaptability, so that the magnetic heading sensor can complete calibration and meet index requirements in harsh environments such as non-uniform rotation, disturbance and magnetic interference.

[0008] A first aspect of the present invention provides a method for calibrating an airborne magnetic heading sensor with high environmental adaptability, comprising:

[0009] Obtain the inherent magnetic field environment parameters of the airborne aircraft of the airborne magnetic heading sensor;

[0010] The inherent magnetic field environment parameters of the onboard aircraft are stored in the storage module of the onboard magnetic heading sensor, replacing the original non-magnetic reference parameters of the onboard magnetic heading sensor;

[0011] Perform eight-point calibration on the airborne magnetic heading sensor.

[0012] Optionally, obtain the inherent magnetic field environment parameters of the airborne aircraft of the airborne magnetic heading sensor, including:

[0013] The airborne magnetic heading sensor measures the inherent magnetic field environment parameters of the airborne aircraft.

[0014] Optionally, the inherent magnetic field environment parameters include: magnetic field direction and magnitude.

[0015] Optionally, perform eight-point calibration on the onboard magnetic heading sensor, including:

[0016] S1, control the magnetic heading sensor to enter the eight-point calibration state through instructions;

[0017] S2, control the magnetic heading sensor to perform uniform circular rotation;

[0018] S3, during rotation, the rotation needs to be stopped at every 45° position, and then the magnetic heading sensor is controlled by command to complete the data collection at that point;

[0019] S4, complete eight-point data collection according to the steps in S3, and obtain eight sets of magnetic field data on the circumference;

[0020] S5. Obtain a calibration result according to the magnetic field data.

[0021] Optionally, the calibration result includes: calibration quality level and environmental interference level.

[0022] Optionally, a calibration result is obtained based on the magnetic field data, including:

[0023] Using the ellipsoid fitting algorithm from the magnetic field data, a linear equation is established

[0024]

[0025] Obtain the least squares of the linear equation through iterative calculation to obtain the ellipsoid center (x, y, z) and the ellipsoid radius;

[0026] Among them, R x ,R y ,R z are the lengths of the three semi-axes, O x ,O y ,O z is the center of the ellipsoid.

[0027] Optionally, the method further comprises:

[0028] Get the radius of the ellipsoid from the linear equation.

[0029] A second aspect of the present invention provides a highly environmentally adaptable calibration device for an airborne magnetic heading sensor, for executing the method described in any one of the first aspects.

[0030] The present invention provides a method and device for calibrating an airborne magnetic heading sensor with high environmental adaptability. When performing eight-point calibration, the magnetic heading sensor can simultaneously eliminate the influence of the inherent magnetic interference of the environment and the shaking of the tractor during starting and stopping on the calibration environmental interference level, and the calibration environmental interference level is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the relationship between the change in magnetic resistance and the change in angle;

[0032] Figure 2 This is the principle diagram of magnetic field data measurement. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0034] like Figure 1 and 2 As shown, the present invention is implemented by the following technical solutions: The principle of eight-point calibration of magnetic heading sensor is to obtain the optimal magnetic field compensation parameters by performing algorithm fitting on eight sets of sampled magnetic field data. Therefore, how to select the appropriate eight sets of magnetic field sampling data during the calibration process will determine whether the calibration operation is successful.

[0035] The built-in data acquisition method of the eight-point calibration of the magnetic heading sensor is to manually select sampling points: during the calibration process, the device stops every 45° rotation, and the operator clicks the "next point" calibration command. After receiving the command, the magnetic heading sensor completes the magnetic field data acquisition at the current position; in the laboratory environment, a special test turntable is used to verify when testing the magnetic heading sensor. The start-stop shaking amplitude of each calibration point is small, and the impact on the magnetic field data acquisition can be ignored. The calibration level can generally meet the standard, and the eight-point calibration results after installation show that the environmental interference level is low, indicating that factors such as the inherent magnetic field of the airborne environment and start-stop vibration have a certain impact on the environmental interference level after calibration.

[0036] Therefore, in order to adapt to the calibration scenario of the installed magnetic heading sensor, after the calibration is completed, the inertial measurement component software adds a save instruction to the magnetic heading sensor, replaces the original non-magnetic laboratory reference parameters with the aircraft's inherent magnetic field environment parameters, and improves the data sampling method of the eight-point calibration of the magnetic heading sensor. A manual selection of sampling points is added, that is, the device continuously collects magnetic field data while the operator rotates the device. At the same time, eight groups of data are selected according to the algorithm for iterative calculation and the optimal solution is retained. This process is repeated until the calibration is completed to avoid shaking interference when the collection is started.

[0037] A first aspect of the present invention provides a method for calibrating an airborne magnetic heading sensor with high environmental adaptability, comprising:

[0038] Obtain the inherent magnetic field environment parameters of the airborne aircraft of the airborne magnetic heading sensor;

[0039] The inherent magnetic field environment parameters of the onboard aircraft are stored in the storage module of the onboard magnetic heading sensor, replacing the original non-magnetic reference parameters of the onboard magnetic heading sensor;

[0040] Perform eight-point calibration on the airborne magnetic heading sensor.

[0041] Optionally, obtain the inherent magnetic field environment parameters of the airborne aircraft of the airborne magnetic heading sensor, including:

[0042] The airborne magnetic heading sensor measures the inherent magnetic field environment parameters of the airborne aircraft.

[0043] Optionally, the inherent magnetic field environment parameters include: magnetic field direction and magnitude.

[0044] Optionally, perform eight-point calibration on the onboard magnetic heading sensor, including:

[0045] S1, control the magnetic heading sensor to enter the eight-point calibration state through instructions;

[0046] S2, control the magnetic heading sensor to perform uniform circular rotation;

[0047] S3, during rotation, the rotation needs to be stopped at every 45° position, and then the magnetic heading sensor is controlled by command to complete the data collection at that point;

[0048] S4, complete eight-point data collection according to the steps in S3, and obtain eight sets of magnetic field data on the circumference;

[0049] S5. Obtain a calibration result according to the magnetic field data.

[0050] Optionally, the calibration result includes: calibration quality level and environmental interference level.

[0051] Optionally, a calibration result is obtained based on the magnetic field data, including:

[0052] Using the ellipsoid fitting algorithm from the magnetic field data, a linear equation is established

[0053]

[0054] Obtain the least squares of the linear equation through iterative calculation to obtain the ellipsoid center (x, y, z) and the ellipsoid radius;

[0055] Among them, R x ,R y ,R z are the lengths of the three semi-axes, O x ,O y ,O z is the center of the ellipsoid. By expanding the above linear equation into a polynomial, we can get:

[0056]

[0057] Multiply both sides by R x After finishing, we can get:

[0058] y 2 A+z 2 B+xC+yD+zE+F=-x 2 (3)

[0059] in

[0060]

[0061] Exemplarily, the ellipsoid radius is obtained using formula (3).

[0062] The output of the three-axis magnetometer in three-dimensional space is a sphere that is symmetrical about (0,0,0). As the environmental magnetic field of the magnetic heading sensor changes or the external interference magnetic field is affected, the output of the three-axis magnetic heading in three-dimensional space will become an ellipsoid, and its center will shift. Therefore, it is necessary to solve the ellipsoid center and ellipsoid radius through ellipsoid fitting (the numerical method is least squares) for the correction and compensation of the three-axis magnetism.

[0063] Exemplarily, after obtaining the center and radius of the ellipsoid, the calibration process data is compensated by calculation results, and the calibration quality level is obtained based on the proximity of the compensated spatial data to the sphere. The environmental interference level is obtained by comparing the difference between the result of this calibration calculation and the result of the last calibration.

[0064] Compared with the prior art, the advantages of the present invention are that the magnetic heading sensor can simultaneously eliminate the influence of the inherent magnetic interference of the environment and the shaking of the tractor when starting and stopping on the calibration environment interference level when performing eight-point calibration, and the calibration environment interference level is relatively high.

Claims

1. A method for calibrating an airborne magnetic heading sensor with high environmental adaptability, characterized in that: include: Obtain the inherent magnetic field environment parameters of the airborne aircraft of the airborne magnetic heading sensor; The inherent magnetic field environment parameters of the airborne aircraft are stored in the storage module of the airborne magnetic heading sensor to replace the original non-magnetic reference parameters of the airborne magnetic heading sensor; Perform eight-point calibration on the airborne magnetic heading sensor.

2. The high environmental adaptability calibration method of an airborne magnetic heading sensor according to claim 1, characterized in that: Obtain the inherent magnetic field environment parameters of the airborne aircraft of the airborne magnetic heading sensor, including: The airborne magnetic heading sensor measures the inherent magnetic field environment parameters of the airborne aircraft.

3. The high environmental adaptability calibration method of an airborne magnetic heading sensor according to claim 1, characterized in that: The inherent magnetic field environment parameters include: magnetic field direction and magnitude.

4. The high environmental adaptability calibration method of an airborne magnetic heading sensor according to claim 1, characterized in that: Perform eight-point calibration on the airborne magnetic heading sensor, including: S1, control the magnetic heading sensor to enter the eight-point calibration state through instructions; S2, control the magnetic heading sensor to perform uniform circular rotation; S3. During rotation, the rotation needs to be stopped at every 45° position, and then the magnetic heading sensor is controlled by instructions to complete the data collection at that point; S4, complete eight-point data collection according to the steps in S3, and obtain eight sets of magnetic field data on the circumference; S5. Obtain a calibration result according to the magnetic field data.

5. The high environmental adaptability calibration method of an airborne magnetic heading sensor according to claim 4, characterized in that: The calibration results include: calibration quality level and environmental interference level.

6. The high environmental adaptability calibration method of an airborne magnetic heading sensor according to claim 4, characterized in that: The calibration results are obtained based on the magnetic field data, including: Using the ellipsoid fitting algorithm from the magnetic field data, a linear equation is established Obtain the least squares of the linear equation through iterative calculation to obtain the ellipsoid center (x, y, z) and the ellipsoid radius; Among them, R x ,R y ,R z are the lengths of the three semi-axes, O x ,O y ,O z is the center of the ellipsoid.

7. The method according to claim 6, a method for calibrating an airborne magnetic heading sensor with high environmental adaptability, characterized in that: The method further comprises: Get the radius of the ellipsoid from the linear equation.

8. A highly environmentally adaptable calibration device for an airborne magnetic heading sensor, characterized in that: Used to perform the method according to any one of claims 1 to 7.

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