A method and system for compensating for magnetic interference from satellite communication antennas of magnetic detection UAVs.

Abstract

This invention discloses a compensation method and system for magnetic interference from satellite communication antennas on a magnetic detection unmanned aerial vehicle (UAV), relating to the field of airborne remote sensing / magnetic detection technology. It is used to compensate for magnetic interference caused by the movement of satellite communication antennas within the UAV platform during aeromagnetic compensation. The key technical points of this invention include: obtaining the magnetic interference generated by the UAV fuselage and the satellite communication antenna using an established magnetic interference model based on the UAV attitude angle, magnetic field data, and satellite communication antenna angle monitoring data; subtracting the magnetic field data collected by the magnetic anomaly detector from the calculated two magnetic interference data to obtain the actual geomagnetic field value, thereby achieving real-time UAV aeromagnetic compensation; wherein the established magnetic interference model includes a fuselage magnetic interference model constructed using the T-L model and a satellite communication antenna magnetic interference model constructed based on the movement angle of the satellite communication antenna. This invention improves the measurement accuracy and data quality of the UAV airborne magnetic detection system.

Description

Technical Field

[0001] This invention relates to the field of airborne remote sensing / magnetic exploration technology, specifically to a compensation method and system for magnetic interference of satellite communication antennas of magnetic exploration UAVs. Background Technology

[0002] Magnetic interference compensation technology for aviation platforms is a technique to compensate for magnetic field interference caused by aviation platforms (including manned aircraft and unmanned aircraft) equipped with magnetic detection equipment for aerial magnetic detection operations. The aim is to improve the accuracy of magnetic detection data and reduce the impact of interfering magnetic fields on data quality. By analyzing the equipment on the UAV platform that may generate magnetic field interference, corresponding mathematical models are established for different types of magnetic field interference. Then, the parameters in the models are solved, and a parameterized model is used to calculate and compensate for magnetic field interference, thereby minimizing the platform's magnetic field interference experienced by the magnetic detection UAV during operation. Based on the sources and forms of platform magnetic field interference, the TL model is used to describe and compensate for interfering magnetic fields from the aircraft body and related to the aircraft's attitude, while the OBE model is used to describe interfering magnetic fields related to the operating conditions of the aircraft's electrical equipment. Satellite communication mechanisms, typically equipped on medium and large UAVs, represent a special type of magnetic field interference source. Because the antenna of a satellite communication system needs to always point towards a specific satellite, a servo mechanism supporting three-axis rotation is often required to adjust the antenna's attitude in real time. This mechanism is driven by a motor, and the parts themselves have a certain degree of magnetism. Therefore, in operation, it exhibits a magnetic field interference mode that combines current interference and the movement of magnetic components. This interference is quite significant under typical operating conditions of a typical magnetic detection UAV system. Therefore, in order to further improve the measurement accuracy and data quality of the UAV airborne magnetic detection system, it is necessary to compensate for the interfering magnetic field caused by the satellite communication mechanism on the platform in real time. Summary of the Invention

[0003] In view of the above problems, this invention proposes a compensation method and system for magnetic interference of satellite communication antennas of magnetic detection UAVs.

[0004] According to one aspect of the present invention, a compensation method for magnetic interference of satellite communication antennas of magnetic detection UAVs is proposed, the method comprising the following steps:

[0005] Acquire the attitude angle of the UAV; acquire magnetic field data collected by the magnetic anomaly detector carried by the UAV and angle monitoring data of the satellite communication antenna;

[0006] Based on the UAV attitude angle, magnetic field data, and satellite communication antenna angle monitoring data, the magnetic interference generated by the UAV fuselage and the satellite communication antenna are obtained using the established magnetic interference model.

[0007] The actual geomagnetic field value is obtained by subtracting the magnetic field data collected by the magnetic anomaly detector from the two calculated magnetic interference data, so as to realize real-time aeromagnetic compensation for UAVs.

[0008] Furthermore, the angle monitoring data of the satellite communication antenna includes heading angle, pitch angle, and polarization angle.

[0009] Furthermore, the established magnetic interference model includes an airframe magnetic interference model constructed using the TL model and a satellite communication antenna magnetic interference model constructed based on the motion angle of the satellite communication antenna. The process of constructing the airframe magnetic interference model using the TL model includes: calculating the cosine value of the angle between the three axes of the magnetometer coordinate system and the geomagnetic field based on the attitude angle of the UAV; calculating the airframe magnetic interference model matrix based on the cosine value; and multiplying the airframe magnetic interference model matrix with a known coefficient matrix to obtain the airframe magnetic interference model.

[0010] Furthermore, the process of constructing the magnetic interference model of the satellite communication antenna based on its motion angle includes: the magnetic interference of the satellite communication antenna includes magnetic interference H generated by the motion of the azimuth mechanism. M1 Magnetic interference H generated by the movement of the antenna principal surface M2 Magnetic interference H generated by the movement of the feed section M3 Based on the attitude angles of the UAV and the angle monitoring data of the satellite communication antenna, the attitude angle α corresponding to the motion of the azimuth mechanism is calculated respectively. M1 ,β M1 ,γ M1 The attitude angle α corresponding to the motion of the antenna principal surface M2 ,β M2 ,γ M2 The attitude angle α corresponding to the motion of the feed section M3 ,β M3 ,γ M3 The cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the geomagnetic field are calculated based on the attitude angles corresponding to the motion of the azimuth mechanism, the motion of the antenna main surface, and the motion of the feed part. The magnetic interference model matrix of the satellite communication antenna is calculated based on the cosine values. The magnetic interference model matrix of the satellite communication antenna is multiplied by the known coefficient matrix to obtain the magnetic interference model of the satellite communication antenna.

[0011] Furthermore, the known coefficient matrix is ​​obtained as follows: the calibrated geomagnetic field values ​​are removed from the actual magnetic field data collected by the magnetic anomaly detector using data from the geomagnetic background database or by filtering, to obtain the calibrated magnetic interference values; the calibrated magnetic interference values ​​are substituted into the airframe magnetic interference model or the satellite communication antenna magnetic interference model, and the airframe magnetic interference model matrix and the satellite communication antenna magnetic interference model matrix are calculated using data collected during calibration standard flight; the coefficient matrix to be determined is obtained by calculating using the least squares method.

[0012] Furthermore, the cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the geomagnetic field, calculated based on the attitude angles of the UAV in the airframe magnetic interference model, include:

[0013] Construct the rotation matrix A(I,D) 1×3 A(I,D) 1×3 = [a1, a2, a3]; a1 = cosIcosD, a2 = cosIsinD, a3 = sinI; I and D represent the geomagnetic tilt and geomagnetic declination, respectively;

[0014] Construct the rotation matrix B(α,β,γ) 3×3 : in,

[0015] b 11 =cosβcosγ

[0016] b 12 =cosβsinγ

[0017] b 13 =-sinβ

[0018] b 21 =sinαsinβcosγ-cosαsinγ

[0019] b 22 =sinαsinβsinγ+cosαcosγ

[0020] b 23 =sinαcosβ

[0021] b 31 =cosαsinβcosγ+sinαsinγ

[0022] b 32 =cosαsinβsinγ-sinαcosγ

[0023] b 33 =cosαcosβ

[0024] In the formula, α, β, and γ represent the attitude angles of the UAV;

[0025] The cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the Earth's magnetic field, cosX, cosY, and cosZ, are calculated using the following formula:

[0026] [cosX, cosY, cosZ]=A(I,D)B(α,β,γ).

[0027] Furthermore, the magnetic interference model matrix of the machine body, calculated based on the cosine value, includes: Let u1 = cosX, u2 = cosY, u3 = cosZ, then the magnetic interference model matrix of the machine body is represented as:

[0028]

[0029] Furthermore, in the satellite communication antenna magnetic interference model, the attitude angle α corresponding to the motion of the azimuth mechanism is calculated based on the attitude angle of the UAV and the angle monitoring data of the satellite communication antenna. M1 ,β M1 γ M1 The attitude angle α corresponding to the motion of the antenna principal surface M2 ,β M2 γ M2 The attitude angle α corresponding to the motion of the feed section M3 ,β M3 γ M3 include:

[0030] α M1 =α,β M1 =β,γ M1 =γ+θ1

[0031] α M2 =α,β M2 =β+θ2,γ M2 =γ+θ1

[0032] α M3 =α+θ3,β M3 =β+θ2,γ M2 =γ+θ1

[0033] In the formula, α, β, and γ represent the attitude angles of the UAV; θ1, θ2, and θ3 represent the heading angle, elevation angle, and polarization angle of the satellite communication antenna, respectively.

[0034] Furthermore, in the satellite communication antenna magnetic interference model, based on the magnetic interference H... M1 H M2 H M3 The cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the geomagnetic field were calculated for each of the corresponding attitude angles, including:

[0035] [cosX M1 cosY M1 cosZ M1 ]=A(I,D)B(α M1 ,β M1 ·γ M1 )

[0036] [cosX M2 cosYM2 ,cosZ M2 ]=A(I,D)B(a M2 ,b M2 ·c M2 )

[0037] [cosX M3 ,cosY M3 ,cosZ M3 ]=A(I,D)B(a M3 ,b M3 ·c M3 )

[0038] Among them,

[0039] b 11Mj =cosβ Mj cosγ Mj

[0040] b 12Mj =cosβ Mj sing Mj

[0041] b 13Mj =-sinβ Mj

[0042] b 21Mj =sina Mj sinβ Mj cosγ Mj -cosα Mj sing Mj

[0043] b 22Mj =sino Mj sinβ Mj sing Mj +cosα Mj cosγ Mj

[0044] b 23Mj =sina Mj cosβ Mj

[0045] b 31Mj =cosα Mj sinβ Mj cosγ Mj +sina Mj sing Mj

[0046] b 32Mj =cosα Mj sinβ Mjsinγ Mj -sinα Mj cosγ Mj

[0047] b 33Mj =cosα Mj cosβ Mj .

[0048] According to another aspect of the present invention, a compensation system for magnetic interference of satellite communication antennas of magnetic detection unmanned aerial vehicles is proposed, the system comprising:

[0049] The data acquisition module is configured to acquire the attitude angle of the UAV; acquire magnetic field data collected by the magnetic anomaly detector carried by the UAV and angle monitoring data of the satellite communication antenna; the angle monitoring data of the satellite communication antenna includes heading angle, pitch angle and polarization angle;

[0050] The magnetic interference data acquisition module is configured to obtain the magnetic interference generated by the UAV fuselage and the magnetic interference generated by the satellite communication antenna based on the UAV attitude angle, magnetic field data, and satellite communication antenna angle monitoring data, using an established magnetic interference model; the established magnetic interference model includes a fuselage magnetic interference model constructed through the TL model and a satellite communication antenna magnetic interference model constructed based on the motion angle of the satellite communication antenna.

[0051] The compensation module is configured to subtract the magnetic field data collected by the magnetic anomaly detector from the two calculated magnetic interference data to obtain the actual geomagnetic field value, so as to realize real-time aeromagnetic compensation for UAVs.

[0052] The beneficial technical effects of this invention are:

[0053] This invention proposes a compensation method and system for magnetic interference from satellite communication antennas on aeromagnetic detection unmanned aerial vehicles (UAVs), used to compensate for magnetic interference caused by the movement of satellite communication antennas within the UAV platform during aeromagnetic compensation. Based on UAV attitude angles, magnetic field data, and satellite communication antenna angle monitoring data, a magnetic interference model is used to obtain the magnetic interference generated by the UAV fuselage and the satellite communication antenna. The difference between the magnetic field data collected by the magnetic anomaly detector and the calculated magnetic interference data is used to obtain the actual geomagnetic field value, thus achieving real-time aeromagnetic compensation for the UAV. This invention improves the measurement accuracy and data quality of UAV aeromagnetic detection systems and can be used on UAV platforms equipped with aeromagnetic anomaly detection systems to compensate for magnetic interference generated by the movement of satellite communication antennas within the platform in real time. Attached Figure Description

[0054] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of the invention are illustrated in the drawings by way of example and not limitation, wherein:

[0055] Figure 1 This is a schematic diagram of the installation position of the satellite communication antenna (mechanism) in the UAV body in an embodiment of the present invention.

[0056] Figure 2 This is a schematic diagram of the overall structure and individually movable parts of the satellite communication antenna (mechanism) in an embodiment of the present invention.

[0057] Figure 3 This is a schematic diagram of the heading angle, elevation angle and polarization angle of the satellite communication antenna (mechanism) in an embodiment of the present invention.

[0058] Figure 4 This is a flowchart of a method for compensating for magnetic interference of satellite communication antennas of magnetic detection UAVs, as described in an embodiment of the present invention.

[0059] Figure 5 This is a schematic diagram of the magnetometer coordinate system, the fuselage coordinate system, and the northeast-northeast coordinate system in an embodiment of the present invention.

[0060] Figure 6 This is a schematic diagram of the structure of a compensation system for magnetic interference of satellite communication antennas of a magnetic detection UAV, as described in an embodiment of the present invention. Detailed Implementation

[0061] The principles and spirit of the invention will now be described with reference to several exemplary embodiments. It should be understood that these embodiments are given merely to enable those skilled in the art to better understand and implement the invention, and are not intended to limit the scope of the invention in any way. Rather, these embodiments are provided to make this disclosure more thorough and complete, and to fully convey the scope of this disclosure to those skilled in the art.

[0062] Those skilled in the art will recognize that embodiments of the present invention can be implemented as a system, apparatus, device, method, or computer program product. Therefore, this disclosure can be specifically implemented in the following forms: entirely hardware, entirely software (including firmware, resident software, microcode, etc.), or a combination of hardware and software. It should be understood herein that any number of elements in the accompanying drawings is for illustrative purposes only and not as a limitation, and any naming is for distinction only and has no limiting meaning.

[0063] During magnetic anomaly detection, UAVs equipped with magnetic anomaly detection systems typically mount the optically pumped magnetometer probe, used to measure the magnetic field, on the wingtip of the UAV platform. This position minimizes magnetic interference from the fuselage. Furthermore, the probe remains relatively stationary with respect to the UAV fuselage during the detection process; it is a fixed installation. The satellite communication antenna, installed within the UAV fuselage, is used for communication between the UAV and the ground station. Since the communication channel is relayed via satellite, the antenna itself incorporates a servo mechanism. To ensure the feed mechanism within the antenna always faces the satellite, there is relative motion between the antenna and the UAV fuselage. Because the optically pumped magnetometer probe remains relatively stationary with respect to the UAV, this relative motion between the antenna and the magnetometer results in magnetic interference at the magnetometer. Since the moving parts of the antenna are made of ferromagnetic material, this relative motion generates magnetic interference at the magnetometer. This interference needs to be eliminated.

[0064] As an example, Figure 1 A schematic diagram of the installation position of a satellite communication antenna within a UAV is provided. The satellite communication antenna is installed in the UAV platform, and its base is mounted in the nose of the aircraft. The relative position of the antenna to the nose is shown in the figure. Schematic diagrams of the overall satellite communication antenna and its individual components are also provided. Figure 2 As shown, the azimuth mechanism can only rotate horizontally, corresponding to the azimuth angle in satellite communication monitoring; the antenna main surface can only rotate in pitch relative to the azimuth mechanism, corresponding to the elevation angle in satellite communication monitoring; the feed section can rotate relative to the antenna main surface, corresponding to the polarization angle in satellite communication monitoring. That is: the horizontal rotation of the azimuth mechanism corresponds to the heading angle θ1 in the monitoring angle; the tilt angle of the antenna main surface relative to the azimuth mechanism corresponds to the elevation angle θ2 in the monitoring angle; the rotation angle of the feed relative to the antenna main surface corresponds to the polarization angle θ3 in the monitoring angle, as shown below. Figure 3 As shown.

[0065] When the satellite communication antenna rotates, the azimuth mechanism, the antenna main surface, and the feed section move independently, and there are certain load-bearing relationships: 1) When the azimuth mechanism rotates horizontally, the antenna main surface and the feed section rotate synchronously around the rotation axis of the azimuth mechanism. 2) When the antenna main surface pitches around its axis, the azimuth mechanism does not move accordingly, while the feed section pitches synchronously around the axis of the antenna main surface. 3) When the feed section rotates around its axis, neither the azimuth mechanism nor the antenna main surface is affected.

[0066] Suppose that the magnetic field data measured by the total field magnetometer during the flight of the UAV platform is an N×1 column vector H. T The actual geomagnetic field value is an N×1 column vector H E The magnetic interference generated by the drone platform fuselage is an N×1 column vector H.I The magnetic interference generated by the satellite communication antenna of the UAV platform is an N×1 column vector H. M Then we have:

[0067] H T =H I +H E +H M (1)

[0068] Of these, only H T It can be directly measured using a total field magnetometer. The ultimate goal of magnetic interference compensation for aircraft platforms is to determine H. E Observing equation (1) above, it can be found that as long as H is calculated... I H M and from H T Subtracting from the middle will give you H. E .

[0069] Therefore, this invention proposes a compensation method for magnetic interference of satellite communication antennas on magnetic detection UAVs, such as... Figure 4 As shown, the method includes the following steps:

[0070] Step 1: Obtain the attitude angle of the UAV; obtain the magnetic field data collected by the magnetic anomaly detector carried by the UAV and the angle monitoring data of the satellite communication antenna;

[0071] Step 2: Based on the UAV attitude angle, magnetic field data, and satellite communication antenna angle monitoring data, use the established magnetic interference model to obtain the magnetic interference generated by the UAV fuselage and the magnetic interference generated by the satellite communication antenna.

[0072] Step 3: Subtract the magnetic field data collected by the magnetic anomaly detector from the two calculated magnetic interference data to obtain the actual geomagnetic field value, so as to realize real-time UAV aeromagnetic compensation.

[0073] The method begins with step one. In step one, the attitude angle of the UAV is obtained; magnetic field data collected by the magnetic anomaly detector carried by the UAV and angle monitoring data of the satellite communication antenna are obtained; the angle monitoring data of the satellite communication antenna includes heading angle, pitch angle and polarization angle.

[0074] According to an embodiment of the present invention, a magnetic anomaly detector is installed on a UAV platform equipped with a satellite communication antenna, and an optically pumped magnetometer is installed at the wingtip of the aircraft. The data collected by the magnetic anomaly detector is then processed. T The aircraft attitude angles α, β, γ and the monitoring data θ1, θ2, θ3 of the satellite communication antenna are collected synchronously.

[0075] Then, step two is executed. In step two, based on the UAV attitude angle, magnetic field data, and angle monitoring data, the magnetic interference generated by the UAV fuselage and the magnetic interference generated by the satellite communication antenna are obtained using the established magnetic interference model. The established magnetic interference model includes a fuselage magnetic interference model constructed through the TL model and a satellite communication antenna magnetic interference model constructed based on the motion angle of the satellite communication antenna.

[0076] In one implementation, the process of constructing the airframe magnetic interference model using the TL model includes: calculating the cosine value of the angle between the three axes of the magnetometer coordinate system and the geomagnetic field based on the attitude angle of the UAV; calculating the airframe magnetic interference model matrix based on the cosine value; and multiplying the airframe magnetic interference model matrix and the constant coefficient matrix to obtain the airframe magnetic interference model.

[0077] According to an embodiment of the present invention, based on the TL model, the magnetic interference generated by the fuselage of the unmanned aerial vehicle platform is defined as follows:

[0078]

[0079] Where m i Let u1 = cosX, u2 = cosY, u3 = cosZ, and u' be an N×16 dimensional matrix composed of the cosine values ​​cosX, cosY, and cosZ. i If i = 1, 2, 3 represents differentiation, then:

[0080]

[0081] And f i This represents a 16×1 dimensional constant coefficient matrix.

[0082] In this embodiment, the cosine values ​​of the angles between the three axes of the computer magnetometer coordinate system and the geomagnetic field, cosX, cosY, cosZ, are determined according to the following process:

[0083] In traditional airborne magnetic survey systems, to obtain the cosine values ​​of the angles between the magnetometer coordinate system (XYZ) and the Earth's magnetic field, a three-component fluxgate is typically installed along the axes of the coordinate system. The cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the Earth's magnetic field, cosX, cosY, and cosZ, are calculated using the outputs of the three-component fluxgates along the three axes. This invention proposes a new alternative method to calculate cosX, cosY, and cosZ using attitude angles α, β, and γ.

[0084] First, construct the rotation matrix A(I,D). 1×3 The rotation matrix is ​​a 1×3 dimensional matrix.

[0085] A(I,D) 1×3 =[a1,a2,a3]

[0086] a1=cosIcosD, a2=cosIsinD, a3=sinI (4)

[0087] In the formula, I and D represent the geomagnetic tilt angle and the geomagnetic declination angle, respectively.

[0088] Next, we construct the rotation matrix B(α,β,γ). 3×3 The rotation matrix is ​​a 3×3 matrix.

[0089]

[0090] Wherein, the rotation matrix B(α,β,γ) 3×3 Each element is calculated from the attitude angles α, β, γ.

[0091] b 11 =cosβcosγ

[0092] b 12 =cosβsinγ

[0093] b 13 =-sinβ

[0094] b 21 =sinαsinβcosγ-cosαsinγ

[0095] b 22 =sinαsinβsinγ+cosαcosγ

[0096] b 23 =sinαcosβ

[0097] b 31 =cosαsinβcosγ+sinαsinγ

[0098] b 32 =cosαsinβsinγ-sinαcosγ

[0099] b 33 =cosαcosβ (6)

[0100] The cosine values ​​cosX, cosY, and cosZ, which are used to replace fluxgate calculations, can be obtained by two rotation matrices.

[0101] [cosX,cosY,cosZ]=A(I,D)B(α,β,γ) (7)

[0102] By combining the formulas, we can obtain the specific expressions for the cosine values ​​cosX, cosY, and cosZ.

[0103] cosX=a1b 11 +a2b21 +a3b 31

[0104] cosY=a1b 12 +a2b 22 +a3b 32

[0105] cosZ=a1b 13 +a2b 23 +a3b 33 (8)

[0106] In one implementation, the process of constructing the magnetic interference model of the satellite communication antenna based on the motion angle of the satellite communication antenna includes: the magnetic interference of the satellite communication antenna includes magnetic interference H generated by the motion of the azimuth mechanism. M1 Magnetic interference H generated by the movement of the antenna principal surface M2 Magnetic interference H generated by the movement of the feed section M3 Based on the attitude angles of the UAV and the angle monitoring data of the satellite communication antenna, the attitude angle α corresponding to the motion of the azimuth mechanism is calculated respectively. M1 ,β M1 ,γ M1 The attitude angle α corresponding to the motion of the antenna principal surface M2 ,β M2 ,γ M2 The attitude angle α corresponding to the motion of the feed section M3 ,β M3 ,γ M3 The cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the geomagnetic field are calculated based on the attitude angles corresponding to the motion of the azimuth mechanism, the motion of the antenna main surface, and the motion of the feed part. The magnetic interference model matrix of the satellite communication antenna is calculated based on the cosine values. The magnetic interference model matrix of the satellite communication antenna is multiplied by the known coefficient matrix to obtain the magnetic interference model of the satellite communication antenna.

[0107] According to an embodiment of the present invention, the magnetic interference caused by the azimuth mechanism, antenna main surface, and feed section of the satellite communication equipment undergoing axial motion is modeled in three parts. It is assumed that the sum of the scalar quantities of the magnetic interference generated at the magnetometer installation position during the simultaneous motion of the three parts of the satellite communication antenna is H as defined above. M The magnetic interference generated by the movement of the orientation mechanism is H M1 The magnetic interference generated by the movement of the antenna principal surface is H. M2 The magnetic interference generated by the movement of the feed section is H M3 Their relationship is as follows:

[0108] H M =H M1 +H M2 +H M3 (9)

[0109] Here, the magnetic interference of the azimuth mechanism, antenna main surface, and feed section in satellite communication equipment is described using a magnetometer coordinate system. Since the azimuth mechanism, antenna main surface, and feed section are three completely undeformed movable units relative to the magnetometer, they can be represented by H... M1 H M2 H M3 Modeling is performed.

[0110]

[0111]

[0112]

[0113] Where, m iMj Indicates by An N×48 dimensional matrix consisting of (j = 1, 2, 3).

[0114] H is being performed here. M1 H M2 H M3 The following assumptions are made when modeling magnetic interference: ① The satellite communication antenna is assumed to be mounted on the axis of the magnetometer coordinate system; ② The initial position of the satellite communication antenna is assumed to be zero in terms of heading angle, elevation angle, and polarization angle. Based on these assumptions, the motion of the satellite communication antenna azimuth mechanism, the antenna main surface, and the feed section can be regarded as a secondary, secondary motion based on the motion of the aircraft itself.

[0115] In the description of the TL model, the magnetic disturbance generated by any ferromagnetic object can be written as a function of the cosine values ​​of the angles between the object's three axes and the direction of the Earth's magnetic field in the magnetometer coordinate system. Therefore, firstly, for H... M1 H M2 H M3 The attitude angles are calculated in the magnetometer coordinate system. The calculation is based on the load-bearing relationship between the motion of the various parts of the satellite communication antenna as described above.

[0116] First, calculate the orientation mechanism H. M1 attitude angle α M1 ,β M1 γ M1 :

[0117] α M1 =α,β M1 =β,γ M1 =γ+θ1 (11)

[0118] Next, calculate the antenna principal surface H. M2 attitude angle α M2 ,β M2 γ M2:

[0119] α M2 = α, β M2 = β + θ2, γ M2 = γ + θ1 (12)

[0120] Finally, calculate the attitude angles α M3 of the feed part H M3 , β M3 , γ M3 :

[0121] α M3 = α + θ3, β M3 = β + θ2, γ M2 = γ + θ1 (13)

[0122] According to H M1 , H M2 , H M3 , calculate the cosine values respectively based on their own attitude angles:

[0123] [cosX M1 , cosY M1 , cosZ M1 = A(I, D)B(α M1 , β M1 , γ M1 )

[0124] [cosX M2 , cosY M2 , cosZ M2 = A(I, D)B(α M2 , β M2 , γ M2 )

[0125] [cosX M3 , cosY M3 , cosZ M3 = A(I, D)B(α M3 , β M3 , γ M3 ) (14) Among them,

[0126] b 11Mj = cosβ Mj cosγ Mj

[0127] b 12Mj = cosβ Mj sinγ Mj

[0128] b 13Mj = -sinβMj

[0129] b 21Mj =sinα Mj sinβ Mj cosγ Mj -cosα Mj sinγ Mj

[0130] b 22Mj =sinα Mj sinβ Mj sinγ Mj +cosα Mj cosγ Mj

[0131] b 23Mj =sinα Mj cosβ Mj

[0132] b 31Mj =cosα Mj sinβ Mj cosγ Mj +sinα Mj sinγ Mj

[0133] b 32Mj =cosα Mj sinβ Mj sinγ Mj -sinα Mj cosγ Mj

[0134] b 33Mj =cosα Mj cosβ Mj

[0135] Next, we calculate based on the cosine value. We can then use the TL model for H M1 H M2 H M3 Modeling is performed.

[0136] Let u M11 =cosX M1 ,u M12 =cosY M1 ,u M13 =cosZ M1 ;u M21 =cosX M2 ,u M22 =cosY M2 ,u M23 =cosZ M2;u M31 =cosX M3 ,u M32 =cosY M3 ,u M33 =cosZ M3 The matrix representation of the body's magnetic interference model is then:

[0137]

[0138] At this point, the magnetic interference H on the UAV platform has been completed. I Satellite antenna magnetic interference H M The modeling of both types of magnetic interference is linear, and their representations during calibration are approximately the same. Therefore, a unified solution can be obtained during calibration by merging the models. The model merging process is as follows:

[0139]

[0140] make Let σ represent the comprehensive model matrix of dimension N×64. 64×1 This represents a 64×1 dimensional matrix of coefficients to be determined.

[0141] In one implementation, the known coefficient matrix is ​​obtained as follows: The calibrated geomagnetic field values ​​are removed from the actual magnetic field data collected by the magnetic anomaly detector using data from a geomagnetic background database or by filtering, to obtain calibrated magnetic interference values; these calibrated magnetic interference values ​​are substituted into the airframe magnetic interference model or the satellite communication antenna magnetic interference model, and the airframe magnetic interference model matrix and the satellite communication antenna magnetic interference model matrix are calculated using data collected during calibration standard flight; the coefficient matrix to be determined is obtained using the least squares method.

[0142] As an example, σ can be calculated using the least squares method, combined with the traditional aeromagnetic compensation calibration process. 64×1 The known coefficient matrix is ​​obtained as follows: the UAV performs a conventional aeromagnetic compensation calibration flight in an area that meets the requirements of conventional calibration flight, during which data H from the magnetic anomaly detector is collected simultaneously. T The aircraft attitude data α, β, γ and the satellite communication antenna monitoring data θ1, θ2, θ3 are used to construct a comprehensive model matrix Δ of magnetic interference between the UAV platform and the satellite communication antenna according to formula (15). N×64 ; Remove the geomagnetic field H of the calibration circle using data from the geomagnetic background database or by filtering. E H T -H E As the input to the left side of the equation (15); σ is calculated using the least squares method in the linear relationship of equation (15). 64×1 .

[0143] Finally, step three is executed. In step three, the difference between the magnetic field data collected by the magnetic anomaly detector and the two calculated magnetic interference data is obtained to obtain the actual geomagnetic field value, so as to realize real-time aeromagnetic compensation for UAVs.

[0144] According to an embodiment of the present invention, an aeromagnetic compensation calibration flight is conducted in an area that meets the requirements of conventional calibration flights, during which data H from a magnetic anomaly detector is collected synchronously. T The aircraft attitude data α, β, γ and the satellite communication antenna monitoring data θ1, θ2, θ3 are used to calculate H in real time using formula (15). I +H M H is calculated using formula (1). E =H T -H I -H M This enables real-time magnetic interference compensation for UAV platforms and satellite communication magnetic interference compensation.

[0145] The coordinate systems involved in the magnetic interference and magnetic compensation problems of the UAV platform in this invention are described below. The magnetometer is mounted at the wingtip of the left wing of the UAV.

[0146] The magnetometer coordinate system XYZ is defined as (in red): the magnetometer is installed at the origin, the positive X-axis is perpendicular to the wing and points towards the nose of the UAV platform, the positive Y-axis is the direction of the UAV platform wing pointing towards the fuselage, and the positive Z-axis is the vertically downward direction that satisfies the right-hand rule.

[0147] The fuselage coordinate system XbYbZb is defined as (black): the intersection of the wing and fuselage (the aircraft's center of mass) is the origin; the direction of the UAV's nose is the positive direction of the Xb axis; the outward direction of the UAV's right wing is the positive direction of the Yb axis; and the vertical downward direction satisfying the right-hand rule is the positive direction of the Zb axis. The aircraft platform's motion angles are defined within this fuselage coordinate system, where the roll angle α is defined as rotation along the Xb axis, the pitch angle β as rotation along the Yb axis, and the yaw angle γ as rotation along the Zb axis. α, β, and γ are collectively referred to as the aircraft's attitude angles, obtained from the output of the UAV's inertial sensors.

[0148] The northeast coordinate system XnYnZn is defined (in green): the point where the wing and fuselage intersect (the aircraft's center of mass) is the origin; the magnetic north direction is the positive direction of the Xn axis; the magnetic east direction is the positive direction of the Yn axis; and the direction perpendicularly downwards towards the Earth's center, satisfying the right-hand rule, is the positive direction of the Zn axis. Two variables are involved in the northeast coordinate system: magnetic inclination and magnetic declination. The angle between the direction of the geomagnetic field and the XnYn plane is called the magnetic inclination I, and the angle between the projection of the geomagnetic field onto the XnYn plane and the Xn direction is called the magnetic declination D. Within the operating range of the UAV, the magnetic inclination and magnetic declination are often considered constants and can be obtained by consulting relevant geographical data or models.

[0149] See the diagram of the coordinate system. Figure 5 As shown, the magnetometer coordinate system and the fuselage coordinate system are related by a translation of the length of a wing along the Y direction. The fuselage coordinate system and the northeast-central coordinate system have their origins coincident. As the UAV's attitude changes in the air, the angle between the northeast-central coordinate system and the fuselage coordinate system constantly changes. Since the fuselage coordinate system and the aircraft coordinate system always remain parallel, the angle between the northeast-central coordinate system and the magnetometer coordinate system also constantly changes.

[0150] Another embodiment of the present invention proposes a compensation system for magnetic interference of satellite communication antennas of magnetic detection UAVs, such as... Figure 6 As shown, the system includes:

[0151] The data acquisition module 610 is configured to acquire the attitude angle of the UAV; acquire magnetic field data collected by the magnetic anomaly detector carried by the UAV and angle monitoring data of the satellite communication antenna; the angle monitoring data of the satellite communication antenna includes heading angle, pitch angle and polarization angle;

[0152] The magnetic interference data acquisition module 620 is configured to obtain the magnetic interference generated by the UAV fuselage and the magnetic interference generated by the satellite communication antenna based on the UAV attitude angle, magnetic field data, and angle monitoring data of the satellite communication antenna, using an established magnetic interference model; the established magnetic interference model includes a fuselage magnetic interference model constructed through the TL model and a satellite communication antenna magnetic interference model constructed based on the motion angle of the satellite communication antenna.

[0153] The compensation module 630 is configured to subtract the magnetic field data collected by the magnetic anomaly detector from the two calculated magnetic interference data to obtain the actual geomagnetic field value, so as to realize real-time aeromagnetic compensation for UAVs.

[0154] For the undescribed portion of the compensation system for magnetic interference of satellite communication antennas of magnetic detection UAVs according to embodiments of the present invention, please refer to the detailed description of the method embodiments above.

[0155] It should be noted that although several units, modules, or sub-modules are mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of the present invention, the features and functions of two or more modules described above can be embodied in one module. Conversely, the features and functions of one module described above can be further divided and embodied by multiple modules.

[0156] Furthermore, although the operations of the method of the present invention are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0157] While the spirit and principles of the invention have been described with reference to several specific embodiments, it should be understood that the invention is not limited to the disclosed specific embodiments, and the division of aspects does not imply that features in these aspects cannot be combined for benefit; such division is merely for ease of description. The invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A compensation method for magnetic interference of satellite communication antennas of magnetic detection UAVs, characterized in that, Includes the following steps: Acquire the attitude angle of the UAV; acquire magnetic field data collected by the magnetic anomaly detector carried by the UAV and angle monitoring data of the satellite communication antenna; the angle monitoring data of the satellite communication antenna includes heading angle, pitch angle and polarization angle; Based on the UAV attitude angle, magnetic field data, and satellite communication antenna angle monitoring data, a magnetic interference model is established to obtain the magnetic interference generated by the UAV fuselage and the satellite communication antenna. The established magnetic interference model includes a fuselage magnetic interference model constructed using a TL model and a satellite communication antenna magnetic interference model constructed based on the satellite communication antenna's motion angle. The process of constructing the fuselage magnetic interference model using the TL model includes: calculating the cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the Earth's magnetic field based on the UAV attitude angle; calculating the fuselage magnetic interference model matrix based on the cosine values; and multiplying the fuselage magnetic interference model matrix with a known coefficient matrix to obtain the fuselage magnetic interference model. The cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the Earth's magnetic field calculated based on the UAV attitude angle in the fuselage magnetic interference model include: Construct rotation matrix : ; and These represent the geomagnetic inclination and geomagnetic declination, respectively. Construct rotation matrix : ;in, ； ； ； ； ； ； ； ； ； In the formula, Indicates the attitude angle of the drone; The cosine value of the angle between the three axes of the magnetometer coordinate system and the geomagnetic field. Calculate using the following formula: ； The actual geomagnetic field value is obtained by subtracting the magnetic field data collected by the magnetic anomaly detector from the two calculated magnetic interference data, so as to realize real-time aeromagnetic compensation for UAVs.

2. The compensation method for magnetic interference of satellite communication antennas of magnetic detection UAVs according to claim 1, characterized in that, The magnetic interference model matrix of the aircraft body, calculated based on the cosine value, includes: Let... The matrix representation of the body's magnetic interference model is then: 。 3. The compensation method for magnetic interference of satellite communication antennas of magnetic detection UAVs according to claim 2, characterized in that, The process of constructing a satellite communication antenna magnetic interference model based on the motion angle of the satellite communication antenna includes: satellite communication antenna magnetic interference includes magnetic interference generated by the motion of the azimuth mechanism. Magnetic interference generated by the movement of the antenna main surface Magnetic interference generated by the movement of the feed section The attitude angles corresponding to the movement of the azimuth mechanism are calculated based on the attitude angles of the UAV and the angle monitoring data of the satellite communication antenna. Attitude angles corresponding to the motion of the antenna principal surface The attitude angle corresponding to the motion of the feed section The cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the geomagnetic field are calculated based on the attitude angles corresponding to the motion of the azimuth mechanism, the motion of the antenna main surface, and the motion of the feed part. The magnetic interference model matrix of the satellite communication antenna is calculated based on the cosine values. The magnetic interference model matrix of the satellite communication antenna is multiplied by the known coefficient matrix to obtain the magnetic interference model of the satellite communication antenna.

4. The compensation method for magnetic interference of satellite communication antennas of magnetic detection UAVs according to claim 3, characterized in that, The known coefficient matrix is ​​obtained as follows: the calibrated geomagnetic field value is removed from the actual magnetic field data collected by the magnetic anomaly detector using data from the geomagnetic background database or by filtering, to obtain the calibrated magnetic interference value; the calibrated magnetic interference value is substituted into the airframe magnetic interference model or the satellite communication antenna magnetic interference model, and the airframe magnetic interference model matrix and the satellite communication antenna magnetic interference model matrix are calculated using data collected during calibration standard flight; the coefficient matrix to be determined is obtained by calculating using the least squares method.

5. A compensation method for magnetic interference of satellite communication antennas for magnetic detection UAVs according to claim 4, characterized in that, In the satellite communication antenna magnetic interference model, the attitude angles corresponding to the azimuth mechanism motion are calculated based on the attitude angles of the UAV and the angle monitoring data of the satellite communication antenna. Attitude angles corresponding to the motion of the antenna principal surface The attitude angle corresponding to the motion of the feed section include: ； ； ； In the formula, Indicates the attitude angle of the drone; , , These represent the heading angle, elevation angle, and polarization angle of the satellite communication antenna, respectively.

6. A compensation method for magnetic interference of satellite communication antennas for magnetic detection UAVs according to claim 5, characterized in that, The satellite antenna magnetic interference model is based on magnetic interference. The cosine values ​​of the angles between the three axes of the magnetometer coordinate system and the geomagnetic field were calculated for each of the corresponding attitude angles, including: ； ； ； in, , =1,2,3; ； ； ； ； ； ； ； ； 。 7. A compensation system for magnetic interference of satellite communication antennas of magnetic detection UAVs, characterized in that, The system is used to implement the magnetic interference compensation method for satellite communication antennas of magnetic detection UAVs as described in any one of claims 1-6; the system includes: The data acquisition module is configured to acquire the attitude angle of the UAV; acquire magnetic field data collected by the magnetic anomaly detector carried by the UAV and angle monitoring data of the satellite communication antenna; the angle monitoring data of the satellite communication antenna includes heading angle, pitch angle and polarization angle; The magnetic interference data acquisition module is configured to obtain the magnetic interference generated by the UAV fuselage and the magnetic interference generated by the satellite communication antenna based on the UAV attitude angle, magnetic field data, and satellite communication antenna angle monitoring data, using an established magnetic interference model; the established magnetic interference model includes a fuselage magnetic interference model constructed through the TL model and a satellite communication antenna magnetic interference model constructed based on the motion angle of the satellite communication antenna. The compensation module is configured to subtract the magnetic field data collected by the magnetic anomaly detector from the two calculated magnetic interference data to obtain the actual geomagnetic field value, so as to realize real-time aeromagnetic compensation for UAVs.

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