Ground-space frequency domain electromagnetic detection coil motion attitude error evaluation system and method

Abstract

The invention belongs to the technical field of ground-space frequency domain electromagnetic detection, and relates to a ground-space frequency domain electromagnetic detection coil motion attitude error evaluation system and method, and the system comprises a motion execution unit which drives a three-component coil magnetic sensor to perform static deflection or periodic swing; the three-component magnetic measurement unit is used for acquiring ground-air electromagnetic three-component magnetic field data acquired by the three-component coil magnetic sensor; the attitude measurement unit is used for acquiring an initial attitude angle, an attitude angle after static deflection and an attitude angle of periodic swing of the three-component coil magnetic sensor; and the processor is used for calculating a magnetic field amplitude attitude error and a magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflections or periodic swings according to the initial attitude angle, the attitude angle after static deflection, the attitude angle after periodic swing and the ground-air electromagnetic three-component magnetic field data. Interference of static deflection and periodic swing amplitude and frequency parameters on electromagnetic data can be quantitatively studied.

Description

Technical Field

[0001] This application belongs to the technical field of ground-air frequency-domain electromagnetic detection, and relates to a system and method for evaluating the motion attitude error of a ground-air frequency-domain electromagnetic detection coil. Background Art

[0002] As a geophysical exploration method, the ground-air frequency-domain electromagnetic method can achieve fine detection of underground structures in a large depth range. In the ground-air frequency-domain electromagnetic method, artificial field sources are arranged on the ground, and a 2 n sequence pseudo-random waveform is transmitted to the earth through grounding wires, and an electromagnetic detection coil is suspended by a drone in the air to collect magnetic field data. However, the receiving coil is easily affected by the flight state of the drone and air turbulence, resulting in unstable measurement during flight, and usually showing two motion modes: one is the periodic low-frequency swing caused by the change of the drone's flight state, and the other is the high-frequency vibration caused by air turbulence. The movement of the receiving coil will inevitably cause the cutting of the geomagnetic induction line, so there is obvious low-frequency motion attitude noise in the magnetic field data, the effective target frequency signal is submerged, affecting the accuracy of the detection result and restricting the deep detection ability of the ground-air frequency-domain electromagnetic system. Therefore, it is of great significance to evaluate the motion attitude error of the ground-air frequency electromagnetic detection coil.

[0003] At present, regarding the motion attitude problem of the ground-air frequency-domain electromagnetic detection coil, the research mainly focuses on the attitude correction algorithm and the design of mechanical vibration isolation devices, but the evaluation of the influence of the coil attitude motion on the measurement data has not been studied yet. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of this application is to provide a system and method for evaluating the motion attitude error of a ground-air frequency-domain electromagnetic detection coil, so as to solve the problem that the attitude of the coil in the drone flight experiment changes randomly and it is difficult to quantitatively evaluate the attitude error.

[0005] This application is implemented as follows. In the first aspect of the embodiments of this application, a system for evaluating the motion attitude error of a ground-air frequency-domain electromagnetic detection coil is provided, including: A motion execution unit for driving a three-component coil magnetic sensor to perform static deflection or periodic swing; A three-component magnetic measurement unit for acquiring the ground-air electromagnetic three-component magnetic field data collected by the three-component coil magnetic sensor, where the ground-air electromagnetic three-component magnetic field data is the received signal excited by the signal emitted by the emission system; An attitude measurement unit for acquiring the initial attitude angle, the attitude angle after static deflection, and the attitude angle of periodic swing of the three-component coil magnetic sensor; A processor, configured to calculate the magnetic field amplitude attitude error and the magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflections or periodic oscillations according to the initial attitude angle, the attitude angle after static deflection, the attitude angle of periodic oscillation, and the terrestrial-air electromagnetic three-component magnetic field data.

[0006] Further, the three-component coil magnetic sensor establishes a two-dimensional coordinate axis in the horizontal plane with its geometric center as the coordinate origin, and the transmission shaft of the motion execution unit is successively coaxially arranged with one of two perpendicular coordinate axes, so that the three-component coil magnetic sensor rotates around two rotation axes respectively.

[0007] Further, the change of the pitch angle is simulated by rotation around one of the rotation axes, and the change of the roll angle is simulated by the other rotation axis.

[0008] Further, the terrestrial-air electromagnetic three-component magnetic field data includes the terrestrial-air electromagnetic three-component magnetic field data collected by the three-component coil magnetic sensor at the initial attitude angle, under static deflection, and during periodic oscillation.

[0009] Further, the processor is also configured to obtain the status information corresponding to the rotation instruction, where the rotation instruction comes from the instruction for the motion execution unit to drive the three-component coil magnetic sensor to complete rotation, and the status information includes the initial attitude angle, the attitude angle after static deflection, and the attitude angle of periodic oscillation; Correlate the status information under the same rotation axis with the terrestrial-air electromagnetic three-component magnetic field data collected within a preset time period when the three-component coil magnetic sensor completes the rotation instruction, so as to obtain the terrestrial-air electromagnetic three-component magnetic field data corresponding to different status information under the same rotation axis; By processing the terrestrial-air electromagnetic three-component magnetic field data under the same rotation axis, obtain the attitude error of the three-component coil magnetic sensor corresponding to different emission frequency points under the same rotation axis.

[0010] Further, the process of obtaining the attitude error of the three-component coil magnetic sensor corresponding to different emission frequency points under the same rotation axis by processing the terrestrial-air electromagnetic three-component magnetic field data under the same rotation axis includes: Perform Fourier transform on the terrestrial-air electromagnetic three-component magnetic field data to obtain the signal frequency domain components at different emission frequency points; Calculate the amplitude and phase of the signal frequency domain components at different emission frequency points; Subtract the amplitude of the signal frequency domain component of the same coil component at the same emission frequency point under static deflection from the amplitude of the signal frequency domain component at the initial attitude angle to obtain the absolute magnetic field amplitude attitude error under static deflection, and obtain the relative magnetic field amplitude attitude error under static deflection through the absolute magnetic field amplitude attitude error under static deflection; The phase of the signal frequency domain component of the same coil component at the same emission frequency point under static deflection is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the magnetic field phase attitude error under static deflection; The amplitude of the signal frequency domain component of the same coil component at the same emission frequency point under periodic swing is subtracted from the amplitude of the signal frequency domain component of the initial attitude angle to obtain the absolute attitude error of the magnetic field amplitude under periodic swing, and the relative attitude error of the magnetic field amplitude under periodic swing is obtained through the absolute attitude error of the magnetic field amplitude under periodic swing; The phase of the signal frequency domain component of the same coil component at the same emission frequency point under periodic swing is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the magnetic field phase attitude error under periodic swing.

[0011] A second aspect of the embodiments of the present application provides a method for evaluating the motion attitude error of a ground-air frequency domain electromagnetic detection coil, including: Obtain static deflection or periodic swing data, where the static deflection or periodic swing data is the corresponding data when a three-component coil magnetic sensor performs static deflection or periodic swing; Obtain the ground-air electromagnetic three-component magnetic field data collected by the three-component coil magnetic sensor, where the ground-air electromagnetic three-component magnetic field data is the received signal excited by the signal emitted by the emission system; Obtain the initial attitude angle, the attitude angle after static deflection, and the attitude angle of periodic swing of the three-component coil magnetic sensor; According to the initial attitude angle, the attitude angle after static deflection, the attitude angle of periodic swing, and the ground-air electromagnetic three-component magnetic field data, calculate the magnetic field amplitude attitude error and the magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflections or periodic swings.

[0012] Further, a two-dimensional coordinate axis is established with the geometric center of the three-component coil magnetic sensor as the coordinate origin, and the three-component coil magnetic sensor rotates respectively with two coordinate axes as the rotation axes. The change of the pitch angle is simulated by rotating around one of the rotation axes, and the roll angle change is simulated by the other rotation axis.

[0013] Further, the state information under the same rotation axis is associated with the ground-air electromagnetic three-component magnetic field data collected within the preset time period when the three-component coil magnetic sensor completes the rotation instruction, and the ground-air electromagnetic three-component magnetic field data corresponding to different state information under the same rotation axis is obtained; the state information includes the initial attitude angle, the attitude angle after static deflection, and the attitude angle of periodic swing; Process the ground-air electromagnetic three-component magnetic field data under the same rotation axis to obtain the attitude error of the three-component coil magnetic sensor corresponding to different emission frequency points under the same rotation axis.

[0014] Further, the geomagnetic three-component magnetic field data under the same rotating shaft are processed to obtain the attitude errors of the three-component coil magnetic sensors corresponding to different transmitting frequency points under the same rotating shaft, including: Calculate the amplitudes and phases of the signal frequency domain components of different transmitting frequency points; Subtract the amplitude of the signal frequency domain component of the same coil component under static deflection at the same transmitting frequency point from the amplitude of the signal frequency domain component of the initial attitude angle to obtain the absolute attitude error of the magnetic field amplitude under static deflection, and obtain the relative attitude error of the magnetic field amplitude under static deflection through the absolute attitude error of the magnetic field amplitude under static deflection; Subtract the phase of the signal frequency domain component of the same coil component under static deflection at the same transmitting frequency point from the phase of the signal frequency domain component of the initial attitude angle to obtain the attitude error of the magnetic field phase under static deflection; Subtract the amplitude of the signal frequency domain component of the same coil component under periodic swing at the same transmitting frequency point from the amplitude of the signal frequency domain component of the initial attitude angle to obtain the absolute attitude error of the magnetic field amplitude under periodic swing, and obtain the relative attitude error of the magnetic field amplitude under periodic swing through the absolute attitude error of the magnetic field amplitude under periodic swing; Subtract the phase of the signal frequency domain component of the same coil component under periodic swing at the same transmitting frequency point from the phase of the signal frequency domain component of the initial attitude angle to obtain the attitude error of the magnetic field phase under periodic swing.

[0015] Compared with the prior art, the system or method of the present application has at least the following beneficial effects: A geomagnetic frequency domain electromagnetic detection coil motion attitude error evaluation system provided by an embodiment of the present application can realize the attitude change of the three-component coil magnetic sensor by arranging a motion execution unit on the ground, can quantitatively study the interference of the static deflection and the periodic swing amplitude and frequency parameters on the electromagnetic data, and can efficiently evaluate the attitude error of the three-component coil magnetic sensor motion. Description of the Drawings

[0016] Figure 1 It is a structural block diagram of a geomagnetic frequency domain electromagnetic detection coil motion attitude error evaluation system provided by an embodiment of the present application; Figure 2 It is a schematic mechanical structure diagram of a geomagnetic frequency domain electromagnetic detection coil motion attitude error evaluation system provided by an embodiment of the present application; Figure 3 It is a flowchart of a geomagnetic frequency domain electromagnetic detection coil motion attitude error evaluation method provided by an embodiment of the present application. Detailed Embodiments

[0017] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0018] To achieve quantitative measurement of the attitude error of a three-component coil magnetic sensor, in a controllable manner, by controlling the relevant motion parameters of static deflection and periodic oscillation, accurate evaluation of the magnetic field amplitude attitude error and magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflections or periodic oscillations is realized.

[0019] In the embodiments of the present application, the three-component coil magnetic sensor is composed of three groups of mutually orthogonal coils, which are respectively used to measure three orthogonal components of the magnetic field, and each coil receives the magnetic field signal in the corresponding direction. The research on the attitude error of the three-component coil magnetic sensor carried by an unmanned aerial vehicle can analyze the influence of attitude deviation on the measurement result, and can optimize the physical structure design of the three-component coil magnetic sensor, such as the size, shape, number of turns of the coil, and the relative position between the coils, etc. For example, determine the optimal relative position of the three-component coil magnetic sensor to reduce the influence brought by mutual inductance. It helps to design a more suitable pre-amplification circuit and signal conditioning circuit to improve the sensitivity and anti-interference ability of the sensor. For example, by analyzing the frequency response characteristics of the sensor under different damping states, determine the optimal damping coefficient adjustment range, etc.

[0020] Studying the attitude error evaluation method can provide a theoretical support for attitude error correction, enable the three-component coil magnetic sensor to obtain accurate measurement results in complex environments (such as mountains, canyons, lakes, etc.), and expand its application range.

[0021] To achieve the above objective, as shown in Figure 1 The embodiments of the present application provide a ground-air frequency-domain electromagnetic detection coil motion attitude error evaluation system. The entire system is set on the ground. Here, setting on the ground is relative to the dynamic flight in the air and belongs to being stationary relative to the ground. For example, it can be fixed on an experimental bench on the ground, or directly fixed on the ground. It can be outdoors or indoors. It includes: A motion execution unit 101, configured to drive the three-component coil magnetic sensor to perform static deflection or periodic oscillation; It can be understood that the motion execution unit 101 has a motor drive structure and a fixed structure for a three-component coil magnetic sensor. The motor drive structure drives the three-component coil magnetic sensor to undergo a static deflection of a certain angle or a dynamic periodic swing of a certain amplitude and frequency according to a given instruction. By changing the connection direction between the three-component coil magnetic sensor and the motion execution unit 101, different attitude change modes can be realized for the three-component coil magnetic sensor, such as: static deflection of the pitch angle, periodic swing of the pitch angle, static deflection of the roll angle, and periodic swing of the roll angle.

[0022] The motion execution unit 101 can set the angle of static deflection and the amplitude and frequency of the periodic swing according to the set or received instructions. The motion execution unit 101 can include a controller, or the parameters can be set by an external controller.

[0023] The three-component magnetic measurement unit 102 is used to obtain the three-component geomagnetic field data of the ground-air electromagnetic field collected by the three-component coil magnetic sensor, and the three-component geomagnetic field data of the ground-air electromagnetic field is the received signal excited by the signal emitted by the emission system; The emission system sends electromagnetic excitation signals of a specific frequency to the ground through a grounded long wire or an emission coil. When these signals propagate underground, they will interact with the underground medium to generate an induced electromagnetic field. The emission system can output electromagnetic signals of multiple frequencies, usually covering a range from low frequency to high frequency. This multi-frequency emission method can adapt to different geological conditions and detection depth requirements. The emission system supports multiple waveforms, such as square waves, pseudo-random waves, etc. Different waveforms are suitable for different detection scenarios. For example, pseudo-random waves can improve the anti-interference ability of the signal.

[0024] The three-component geomagnetic field data of the ground-air electromagnetic field is the received signal collected by the three-component coil magnetic sensor excited by the signal emitted by the emission system.

[0025] The input of the three-component magnetic measurement unit 102 is connected to the three-component coil magnetic sensor to record the three-component geomagnetic field data of the ground-air electromagnetic field collected by the three-component coil magnetic sensor. It can be understood that the three-component magnetic measurement unit 102 can have functions such as pre-amplification, signal conditioning, and data transmission in a wired or wireless manner for the input three-component geomagnetic field data of the ground-air electromagnetic field, as well as circuits for implementing the functions.

[0026] The attitude measurement unit 103 is used to obtain the initial attitude angle, the attitude angle after static deflection, and the attitude angle of the periodic swing of the three-component coil magnetic sensor; The attitude measurement unit 103 is linked with the three-component coil magnetic sensor and fixed together with it. The attitude measurement unit 103 may include a triaxial accelerometer for measuring the accelerations of the three-component coil magnetic sensor in three orthogonal directions. By detecting the components of the gravitational acceleration in different directions, the pitch angle and roll angle of the three-component coil magnetic sensor can be calculated. It may also include a triaxial gyroscope for measuring the angular velocity of the three-component coil magnetic sensor around the rotation axis. By integrating the angular velocity, the real-time attitude angle of the three-component coil magnetic sensor can be obtained.

[0027] The processor 104 is configured to calculate the magnetic field amplitude attitude error and magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflection angles or periodic oscillations based on the initial attitude angle, the attitude angle after static deflection, the attitude angle of periodic oscillation, and the terrestrial-airborne electromagnetic three-component magnetic field data. The processor 104 is an electronic device with computing capabilities, having the function of data transmission by wired or wireless means and the circuits for implementing the function. It receives the terrestrial-airborne electromagnetic three-component magnetic field data of the three-component magnetic measurement unit 102, receives the initial attitude angle, the attitude angle after static deflection, and the attitude angle of periodic oscillation of the three-component coil magnetic sensor obtained by the attitude measurement unit 103, and receives the angle of static deflection, the amplitude and frequency of periodic oscillation set by the motion execution unit 101.

[0028] And the rotation axis number corresponding to the current detection of the three-component coil magnetic sensor can be input through the processor 104. Based on the initial attitude angle, the attitude angle after static deflection, the attitude angle of periodic oscillation, and the terrestrial-airborne electromagnetic three-component magnetic field data, calculate the magnetic field amplitude attitude error and magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflection angles or periodic oscillations, including, for example, the magnetic field amplitude attitude error and magnetic field phase attitude error under pitch angle static deflection, pitch angle periodic oscillation, roll angle static deflection, and roll angle periodic oscillation. The magnetic field amplitude attitude error includes the magnetic field amplitude absolute attitude error and the magnetic field amplitude relative attitude error.

[0029] Based on the terrestrial-airborne electromagnetic three-component magnetic field data at the initial attitude angle, calculate the amplitude and phase of the signal frequency domain components corresponding to each coil component at each emission frequency point at the initial attitude angle; here, the coil component refers to a certain coil that makes up the three-component coil magnetic sensor.

[0030] The amplitude of the signal frequency domain component of the same coil component at the same emission frequency point under static deflection is subtracted from the amplitude of the signal frequency domain component of the initial attitude angle to obtain the absolute attitude error of the magnetic field amplitude under static deflection, and the relative attitude error of the magnetic field amplitude under static deflection is obtained through the absolute attitude error of the magnetic field amplitude under static deflection; by calculating at different emission frequency points, the absolute attitude error of the magnetic field amplitude under static deflection and the relative attitude error of the magnetic field amplitude under static deflection of each coil component at different emission frequency points are obtained.

[0031] The phase of the signal frequency domain component of the same coil component at the same emission frequency point under static deflection is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the attitude error of the magnetic field phase under static deflection; by calculating at different emission frequency points, the attitude error of the magnetic field phase under static deflection of each coil component at different emission frequency points is obtained.

[0032] The amplitude of the signal frequency domain component of the same coil component at the same emission frequency point under periodic swing is subtracted from the amplitude of the signal frequency domain component of the initial attitude angle to obtain the absolute attitude error of the magnetic field amplitude under periodic swing, and the relative attitude error of the magnetic field amplitude under periodic swing is obtained through the absolute attitude error of the magnetic field amplitude under periodic swing; The phase of the signal frequency domain component of the same coil component at the same emission frequency point under periodic swing is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the attitude error of the magnetic field phase under periodic swing; In an embodiment, a two-dimensional coordinate axis is established in the horizontal plane with the geometric center of the three-component coil magnetic sensor as the coordinate origin, and the transmission shaft of the motion execution unit 101 is successively selected to be coaxially arranged with one of the two perpendicular coordinate axes, so that the three-component coil magnetic sensor rotates around the two rotation axes respectively. The two perpendicular coordinate axes are arbitrary coordinate axes, and there is no requirement for the relative orientation of the three coils of the three-component coil magnetic sensor. For the convenience of installation and fixation with the motion execution unit 101, an installation structure can be set on the housing of the three-component coil magnetic sensor and fixed to the transmission shaft of the motion execution unit 101. Here, the installation structure can be an installation hole or a buckle for butt joint and fixation with the transmission shaft, etc. There is no limitation here. After the fixation is realized for installation, it is convenient to disassemble and replace the direction, or the replacement of the two coordinate axes coaxial with the transmission shaft can be automatically realized. There is no front-back distinction between the two perpendicular coordinate axes, and the transmission shaft of the motion execution unit 101 can arbitrarily select one of the coordinate axes to be coaxial and then select the other coordinate axis to be coaxial. One of the coordinate axes is used as the rotation axis to simulate the pitch angle, and the other coordinate axis is used as the rotation axis to simulate the roll angle.

[0033] In one embodiment, the processor 104 is further configured to obtain the status information corresponding to the rotation instruction, where the rotation instruction is from the instruction for the motion execution unit 101 to drive the three-component coil magnetic sensor to complete rotation, and the status information includes the initial attitude angle, the attitude angle after static deflection, and the attitude angle of periodic swing. Obtaining the status information corresponding to the rotation instruction can be obtained by the processor 104 according to the rotation instruction for the three-component coil magnetic sensor executed by the motion execution unit 101 to perform static deflection or periodic swing. According to the rotation instruction, it can be known whether the three-component coil magnetic sensor is to perform static deflection or periodic swing, as well as the angle of static deflection and the amplitude and frequency of periodic swing. The rotation instruction can only represent the rotation parameters of the three-component coil magnetic sensor with preset values. When there is no rotation instruction, the three-component coil magnetic sensor is in a stationary state.

[0034] The status information corresponding to the rotation instruction includes the initial attitude angle, the attitude angle after static deflection, and the attitude angle of periodic swing. The status information is obtained based on the initial attitude angle, the attitude angle after static deflection, and the attitude angle of periodic swing of the three-component coil magnetic sensor acquired by the attitude measurement unit 103.

[0035] In one embodiment, the status information under the same rotation axis is associated with the geo-air electromagnetic three-component magnetic field data collected within a preset time period when the three-component coil magnetic sensor completes the rotation instruction, so as to obtain the geo-air electromagnetic three-component magnetic field data corresponding to different status information under the same rotation axis. It can be understood that when the status of the initial attitude angle can be obtained through association, the geo-air electromagnetic three-component magnetic field data collected by the three-component magnetic measurement unit 102; when the status of the attitude angle after static deflection is obtained, the geo-air electromagnetic three-component magnetic field data collected by the three-component magnetic measurement unit 102, and when the status of the attitude angle of periodic swing is obtained, the geo-air electromagnetic three-component magnetic field data collected by the three-component magnetic measurement unit 102.

[0036] It should be noted that in the state of the initial attitude angle, the motion execution unit 101 is also in the startup state, controlling the three-component coil magnetic sensor to maintain the initial attitude angle without being affected by external interference and moving. At this time, the emission system emits a signal, and the three-component magnetic measurement unit 102 and the attitude measurement unit 103 collect data and transmit it to the processor 104. The control process can be implemented by an additional controller or integrated in the processor 104. Taking the processor 104 as the host, it controls the startup of the motion execution unit 101, the attitude measurement unit 103, and the three-component magnetic measurement unit 102. In order to synchronize with the emission system, the processor 104 also needs to set a GPS synchronization module to synchronize the emission system and obtain the startup and shutdown times of the emission signal. And by setting a GPS synchronization module inside the three-component magnetic measurement unit 102, a GPS synchronization module in the attitude measurement unit 103, and a GPS synchronization module in the emission system, a total of three GPS synchronization modules are used to achieve the synchronization of the magnetic field signal, attitude, and emission current.

[0037] Therefore, in one embodiment, the processor 104 is further configured to control the startup and shutdown timings of the motion execution unit 101, the three-component magnetic measurement unit 102, and the attitude measurement unit 103, and use the GPS synchronization module to synchronize the emission system. And it receives the data of the motion execution unit 101, the three-component magnetic measurement unit 102, and the attitude measurement unit 103.

[0038] In one embodiment, the processor 104 processes the ground-air electromagnetic three-component magnetic field data under the same rotating shaft to obtain the attitude errors of the three-component coil magnetic sensors corresponding to different emission signal frequency points under the same rotating shaft.

[0039] The three-component coil magnetic sensor rotates respectively with two coordinate axes as the rotating shafts. One rotating shaft simulates the change of the pitch angle, and the other rotating shaft simulates the change of the roll angle.

[0040] For the same rotating shaft, at least one static deflection and periodic swing need to be performed. During the static deflection and periodic swing, the ground-air electromagnetic three-component magnetic field data, as well as the initial attitude angle of the three-component coil magnetic sensor, the attitude angle of the static deflection, and the attitude angle of the periodic swing are collected. Then, through the processing of the processor 104, the magnetic field amplitude attitude error and magnetic field phase attitude error during the static deflection or periodic swing under the same rotating shaft are obtained.

[0041] In one embodiment, the ground-air electromagnetic three-component magnetic field data is subjected to Fourier transform to obtain the signal frequency domain components of multiple different emission frequency points; Calculate the amplitudes and phases of the signal frequency domain components of different emission frequency points; The amplitude of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection is subtracted from the amplitude of the signal frequency domain component of the initial attitude angle to obtain the absolute attitude error of the magnetic field amplitude under static deflection, and the relative attitude error of the magnetic field amplitude under static deflection is obtained through the absolute attitude error of the magnetic field amplitude under static deflection; The phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the attitude error of the magnetic field phase under static deflection; The amplitude of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic oscillation is subtracted from the amplitude of the signal frequency domain component of the initial attitude angle to obtain the absolute attitude error of the magnetic field amplitude under periodic oscillation, and the relative attitude error of the magnetic field amplitude under periodic oscillation is obtained through the absolute attitude error of the magnetic field amplitude under periodic oscillation; The phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic oscillation is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the attitude error of the magnetic field phase under periodic oscillation Since the transmitted signal contains multiple transmission frequency points, the influence of the attitude error on the received signals at different transmission frequency points is also different. By performing Fourier transform on the three-component magnetic field data of the ground-air electromagnetic field, the signal frequency domain components at multiple different transmission frequency points are obtained, and the attitude error is calculated for each transmission frequency point.

[0042] The following is a feasible structure for implementing the above-mentioned ground-air frequency domain electromagnetic detection coil motion attitude error evaluation system. Refer to Figure 2 the schematic mechanical structure diagram of a ground-air frequency domain electromagnetic detection coil motion attitude error evaluation system provided by an embodiment of the present application shown in the figure. It includes: The motion execution unit 101 includes: a servo motor 201, a programmable logic controller 202, and a motor driver 203. Among them: the servo motor 201 performs static deflection or periodic oscillation according to given parameters. The programmable logic controller is used to store and execute the operation program of the servo motor 201, send a motor control signal to the motor driver 203, and the motor driver 203 is responsible for converting the control signal into the working current of the servo motor 201. The programmable logic controller 202 is built-in with a transmission module for communicating with the processor 104.

[0043] The three-component magnetic measurement unit 102 uses a coil receiver 209 to measure and record the three-component magnetic field data of the ground-air electromagnetic field, and also has a communication module for communication connection with the processor 104.

[0044] The attitude measurement unit 103 includes an attitude measurement sensor 210, a battery 211, and an attitude data recorder 212. The battery 211 supplies power to the attitude measurement sensor 210 and the attitude data recorder 212. The attitude measurement sensor 210 is a three-axis gyroscope that measures the angular velocity of a three-component coil magnetic sensor around the rotation axis. By integrating the angular velocity, the real-time attitude angle of the three-component coil magnetic sensor can be obtained, and it is transmitted to the processor 104 through the attitude data recorder 212 and then through the communication module.

[0045] The mechanical support structure includes a base 204, a support 205, a transmission shaft 206, and a bearing 207. By mounting the servo motor 201 and the three-component coil magnetic sensor, it ensures that the servo motor can drive the three-component coil magnetic sensor to rotate smoothly and reduces the friction during rotation. The base 204 is placed on the ground or an experimental table. Three parallel supports 205 are provided on the base 204 for fixing the servo motor 201 and the transmission shaft 206 of the servo motor. Bearings 207 are provided at the tops of two of the supports 205 to reduce friction. The programmable logic controller 202, the motor driver 203, and the coil receiver 209 are all installed on the base 204.

[0046] After the base 204 is placed on the horizontal ground, the bottom of each support 205 is connected to the base 204 by six fastening screws, and the top is connected to the transmission shaft 206 through a bearing 207. One end of the transmission shaft 206 is connected to the servo motor 201, and the other end is connected to the three-component coil magnetic sensor.

[0047] The three-component coil magnetic sensor is arranged in a housing 208. Circular holes with the same diameter as the transmission shaft 206 are provided at the centers of the four side faces of the housing 208. The transmission shaft 206 passes through the center, and torque is transmitted by relying on a type A flat key. The three-component coil magnetic sensor together with the transmission shaft 206 is mounted by the support 205. The three-axis induced electromotive force output by the three-component coil magnetic sensor is recorded by the coil receiver 209.

[0048] The attitude measurement sensor 210, the battery 211, and the attitude data recorder 212 are all installed on the mounting plate provided on the top surface of the housing 208 of the three-component coil magnetic sensor.

[0049] In one embodiment, the present application embodiment also provides a method for evaluating the motion attitude error of a ground-air frequency-domain electromagnetic detection coil. Referring to the ground-air frequency-domain electromagnetic detection coil motion attitude error evaluation system, the content can be used for corresponding explanation. See Figure 3 The flowchart of a method for evaluating the motion attitude error of a ground-air frequency-domain electromagnetic detection coil shown in the figure includes: S301 Obtain static deflection or periodic swing data, where the static deflection or periodic swing data is the corresponding data when the three-component coil magnetic sensor performs static deflection or periodic swing; S302 acquires the three-component magnetic field data of the ground-air electromagnetic field collected by the three-component coil magnetic sensor, and the three-component magnetic field data of the ground-air electromagnetic field is the received signal under the excitation of the signal emitted by the emission system; S303 acquires the initial attitude angle, the attitude angle of static deflection, and the attitude angle of periodic swing of the three-component coil magnetic sensor; S304 calculates the magnetic field amplitude attitude error and the magnetic field phase attitude error of the three-component coil magnetic sensor under static deflection or periodic swing according to the initial attitude angle, the attitude angle after static deflection, the attitude angle of periodic swing, and the three-component magnetic field data of the ground-air electromagnetic field.

[0050] In one embodiment, the three-component coil magnetic sensor establishes a two-dimensional coordinate axis in the horizontal plane with the geometric center as the coordinate origin, and the three-component coil magnetic sensor rotates respectively with two coordinate axes as the rotation axes. The change of the pitch angle is simulated by rotating around one of the rotation axes, and the roll angle change is simulated by the other rotation axis.

[0051] In one embodiment, the state information under the same rotation axis is associated with the three-component magnetic field data of the ground-air electromagnetic field collected within the preset time period when the three-component coil magnetic sensor completes the rotation instruction, and the three-component magnetic field data of the ground-air electromagnetic field corresponding to different state information under the same rotation axis is obtained; the state information includes the initial attitude angle, the attitude angle of static deflection, and the attitude angle of periodic swing; In one embodiment, the three-component magnetic field data of the ground-air electromagnetic field under the same rotation axis is processed to obtain the attitude error of the three-component coil magnetic sensor corresponding to different emission signal frequency points under the same rotation axis, including: Performing Fourier transform on the three-component magnetic field data of the ground-air electromagnetic field to obtain the signal frequency domain components of multiple different emission frequency points; Calculating the amplitude and phase of the signal frequency domain components of different emission frequency points; Subtracting the amplitude of the signal frequency domain component of the same coil component under static deflection at the same emission frequency point from the amplitude of the signal frequency domain component of the initial attitude angle to obtain the absolute magnetic field amplitude attitude error under static deflection, and obtaining the relative magnetic field amplitude attitude error under static deflection through the absolute magnetic field amplitude attitude error under static deflection; Subtracting the phase of the signal frequency domain component of the same coil component under static deflection at the same emission frequency point from the phase of the signal frequency domain component of the initial attitude angle to obtain the magnetic field phase attitude error under static deflection; Subtracting the amplitude of the signal frequency domain component of the same coil component under periodic swing at the same emission frequency point from the amplitude of the signal frequency domain component of the initial attitude angle to obtain the absolute magnetic field amplitude attitude error under periodic swing, and obtaining the relative magnetic field amplitude attitude error under periodic swing through the absolute magnetic field amplitude attitude error under periodic swing; The phase of the signal frequency domain component of the same coil component under periodic oscillation at the same emission frequency point is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the magnetic field phase attitude error under periodic oscillation. In conjunction with the specific process, the embodiments of the present application are explained. A method for evaluating the motion attitude error of a ground-air frequency domain electromagnetic detection coil includes: Calibrate the first initial attitude angle with reference to the north celestial east coordinate system . 、 、 Are respectively the first initial angles of the three-component coil magnetic sensor. The first in the first initial attitude angle and the first initial angle here is to distinguish from the initial attitude angle of another rotating shaft. Record the ground-air electromagnetic three-component magnetic field data measured by the three-component coil magnetic sensor at the first initial attitude angle at this time , Represents the three-axis orthogonal direction.

[0052] At a certain pitch angle static deflection The three-component coil magnetic sensor undergoes a pitch angle static deflection. Measure the attitude angle of the three-component coil magnetic sensor after the static deflection as . Record the ground-air electromagnetic three-component magnetic field data measured by the three-component coil magnetic sensor at the pitch angle static deflection at this time , Represents the three-axis orthogonal direction.

[0053] Output a pitch angle periodic oscillation, the oscillation amplitude Is the same as the magnitude of the pitch angle static deflection, and the oscillation frequency is . The three-component coil magnetic sensor undergoes a pitch angle periodic oscillation. Measure the attitude angle of the pitch angle periodic oscillation of the three-component coil magnetic sensor . Is time. Record the ground-air electromagnetic three-component magnetic field data measured by the three-component coil magnetic sensor at the pitch angle periodic oscillation at this time .

[0054] Remove the three-component coil magnetic sensor from the shaft and install the three-component coil magnetic sensor in another direction. Calibrate the second initial attitude angle of the three-component coil magnetic sensor . Are respectively the second initial angles of the three coils in the three-component coil magnetic sensor. Record the ground-air electromagnetic three-component magnetic field data measured by the three-component coil magnetic sensor at the second initial attitude angle at this time .

[0055] At a certain static deflection Under such circumstances, the three-component coil magnetic sensor undergoes a static roll angle deflection, and the attitude angle after measuring the static roll angle deflection of the three-component coil magnetic sensor is measured. Record the data of the three-component geomagnetic field in the air-earth electromagnetic field measured by the three-component coil magnetic sensor under the static roll angle deflection at this time. .

[0056] The output exhibits a periodic oscillation with an oscillation amplitude of , which is consistent with the static deflection, and the oscillation frequency is . The three-component coil magnetic sensor undergoes a periodic roll angle oscillation, and the attitude angle of the three-component coil magnetic sensor under the periodic roll angle oscillation is measured. Record the data of the three-component geomagnetic field in the air-earth electromagnetic field measured by the three-component coil magnetic sensor under the periodic roll angle oscillation at this time. .

[0057] Perform Fourier transform (FFT) on the above-mentioned six groups of measured data of the three-component geomagnetic field in the air-earth electromagnetic field respectively. Let the signal to be analyzed be : : , where represents the result of the Fourier transform, is the angular frequency of the signal transmitted by the transmitting system, , represents the data of the three-component geomagnetic field in the air-earth electromagnetic field.

[0058] Calculate the amplitude and phase of the signal frequency domain components of the three-component geomagnetic field data in the air-earth electromagnetic field at each transmitting frequency point: , , where is the amplitude, is the phase, and the signal frequency domain component is the frequency domain signal of the magnetic field component under different coil components.

[0059] For the case of the static pitch angle deflection , the absolute attitude error of the magnetic field amplitude under the static pitch angle deflection , represents the amplitude under the static pitch angle deflection of the th coil component, represents the amplitude under the first initial attitude angle of the th coil component. The relative attitude error of the magnetic field amplitude under the static pitch angle deflection , the phase attitude error of the magnetic field under the static pitch angle deflection , represents the Phase under the static deflection of the pitch angle of a coil component Indicates the phase under the first initial attitude angle of the

[0060] For the case of periodic pitching the absolute attitude error of the magnetic field amplitude under periodic pitching of the pitch angle , is the amplitude under the periodic pitching of the pitch angle of the th coil component, the relative attitude error of the magnetic field amplitude under periodic pitching of the pitch angle , the phase attitude error of the magnetic field under periodic pitching of the pitch angle , Indicates the phase under the periodic pitching of the pitch angle of the

[0061] For the case of static roll angle deflection the absolute attitude error of the magnetic field amplitude under static roll angle deflection , is the amplitude under the second initial attitude angle of the th coil component, the amplitude of the th coil component under static roll angle deflection, the relative attitude error of the magnetic field amplitude under static roll angle deflection , the phase attitude error of the magnetic field under static roll angle deflection Indicates the phase under the static roll angle deflection of the Indicates the phase under the second initial attitude angle of the

[0062] For the case of periodic roll angle oscillation the absolute attitude error of the magnetic field amplitude under periodic roll angle oscillation , the amplitude of the th coil component under periodic roll angle oscillation, the relative attitude error of the magnetic field amplitude under periodic roll angle oscillation , the phase attitude error of the magnetic field under periodic roll angle oscillation Indicates the phase under the periodic roll angle oscillation of the

[0063] So far, the attitude error evaluation under static deflection and periodic swing has been completed. By setting a series of static deflections and performing attitude error evaluations respectively, the curves of the absolute (relative) attitude error of the magnetic field amplitude and the magnetic field phase error of the three-component coil magnetic sensor under static deflection with respect to the static deflection can be plotted.

[0064] By setting a series of periodic swing amplitudes and performing attitude error evaluations respectively, the curves of the absolute (relative) attitude error of the magnetic field amplitude and the magnetic field phase attitude error of the three-component coil magnetic sensor under periodic swing with respect to the periodic swing amplitude can be plotted.

[0065] It is also possible to set a series of periodic swing frequencies, perform attitude error evaluations respectively, and then plot the curves of the absolute (relative) attitude error of the magnetic field amplitude and the magnetic field phase attitude error of the three-component coil magnetic sensor under periodic swing with respect to the periodic swing frequency.

[0066] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. A ground-to-space frequency domain electromagnetic detection coil motion attitude error assessment system, characterized in that: include: A motion execution unit, used for driving the three-component coil magnetic sensor to perform static deflection or periodic swing; A three-component magnetic measurement unit is used to obtain the ground-air electromagnetic three-component magnetic field data collected by the three-component coil magnetic sensor, wherein the ground-air electromagnetic three-component magnetic field data is a received signal excited by the transmitting signal of the transmitting system; An attitude measurement unit, used to obtain the initial attitude angle, the attitude angle after static deflection and the attitude angle of periodic swing of the three-component coil magnetic sensor; The processor is used to calculate the magnetic field amplitude attitude error and magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflections or periodic swings according to the initial attitude angle, the attitude angle after static deflection, the attitude angle after periodic swing, and the three-component magnetic field data of the ground and air electromagnetics.

2. The ground-to-space frequency domain electromagnetic detection coil motion attitude error assessment system according to claim 1, characterized in that: The three-component coil magnetic sensor establishes a two-dimensional coordinate axis in the horizontal plane with the geometric center as the coordinate origin, and the transmission shaft of the motion execution unit is sequentially coaxially arranged with one of the two perpendicular coordinate axes, so that the three-component coil magnetic sensor rotates around the two rotating axes respectively.

3. The ground-to-space frequency domain electromagnetic detection coil motion attitude error assessment system according to claim 2, characterized in that: The pitch angle change is simulated by rotating around one of the rotation axes, and the roll angle change is simulated by the other rotation axis.

4. The ground-to-space frequency domain electromagnetic detection coil motion attitude error assessment system according to claim 1, characterized in that: The ground-to-air electromagnetic three-component magnetic field data includes ground-to-air electromagnetic three-component magnetic field data collected by the three-component coil magnetic sensor at the initial attitude angle, static deflection and periodic swing.

5. The ground-to-space frequency domain electromagnetic detection coil motion attitude error assessment system according to claim 4, characterized in that: The processor is also used to obtain state information corresponding to the rotation instruction, the rotation instruction comes from the instruction of the motion execution unit to drive the three-component coil magnetic sensor to complete the rotation, and the state information includes the initial attitude angle, the attitude angle after static deflection and the attitude angle of periodic swing; The state information of the same rotating shaft is associated with the ground-air electromagnetic three-component magnetic field data collected within a preset time period when the three-component coil magnetic sensor completes the rotation instruction, so as to obtain the ground-air electromagnetic three-component magnetic field data corresponding to different state information of the same rotating shaft; By processing the three-component magnetic field data of the ground and air electromagnetics under the same rotation axis, the attitude error of the three-component coil magnetic sensor corresponding to different transmitting frequency points under the same rotation axis is obtained.

6. The ground-to-space frequency domain electromagnetic detection coil motion attitude error assessment system according to claim 5, characterized in that: The method of obtaining the attitude errors of the three-component coil magnetic sensors corresponding to different transmitting frequency points under the same rotation axis by processing the three-component ground-air electromagnetic magnetic field data under the same rotation axis includes: Perform Fourier transform on the three-component magnetic field data of the ground and space electromagnetics to obtain the frequency domain components of the signals at different transmitting frequency points; Calculate the amplitude and phase of the signal frequency domain components at different transmission frequency points; The absolute attitude error of the magnetic field amplitude under static deflection is obtained by subtracting the amplitude of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection from the amplitude of the signal frequency domain component of the initial attitude angle, and the relative attitude error of the magnetic field amplitude under static deflection is obtained through the absolute attitude error of the magnetic field amplitude under static deflection; The phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the magnetic field phase attitude error under static deflection; The absolute attitude error of the magnetic field amplitude under periodic swing is obtained by subtracting the amplitude of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing from the amplitude of the signal frequency domain component of the initial attitude angle, and the relative attitude error of the magnetic field amplitude under periodic swing is obtained through the absolute attitude error of the magnetic field amplitude under periodic swing; The phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the magnetic field phase attitude error under periodic swing.

7. A method for evaluating the motion attitude error of a ground-to-space frequency-domain electromagnetic detection coil, characterized in that: include: Acquiring static deflection or periodic swing data, wherein the static deflection or periodic swing data is data corresponding to when the three-component coil magnetic sensor performs static deflection or periodic swing; Acquire the ground-air electromagnetic three-component magnetic field data collected by the three-component coil magnetic sensor, wherein the ground-air electromagnetic three-component magnetic field data is a received signal excited by a transmitting signal of a transmitting system; Obtaining the initial attitude angle, attitude angle after static deflection and attitude angle of periodic swing of the three-component coil magnetic sensor; According to the initial attitude angle, the attitude angle after static deflection, the attitude angle after periodic swing and the three-component magnetic field data of the ground and air electromagnetic, the magnetic field amplitude attitude error and magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflections or periodic swings are calculated.

8. The method for evaluating the motion attitude error of ground-to-space frequency-domain electromagnetic detection coil according to claim 7, characterized in that: The three-component coil magnetic sensor establishes a two-dimensional coordinate axis with the geometric center as the coordinate origin, so that the three-component coil magnetic sensor rotates with two coordinate axes as rotation axes respectively, and simulates the pitch angle change by rotating around one of the rotation axes, and simulates the roll angle change by the other rotation axis.

9. The method for evaluating the motion attitude error of ground-to-space frequency-domain electromagnetic detection coil according to claim 8, characterized in that: The state information of the same rotating shaft is associated with the ground-to-air electromagnetic three-component magnetic field data collected within a preset time period when the three-component coil magnetic sensor completes the rotation instruction, so as to obtain the ground-to-air electromagnetic three-component magnetic field data corresponding to different state information of the same rotating shaft; the state information includes the initial attitude angle, the attitude angle after static deflection and the attitude angle of periodic swing; The three-component magnetic field data of the ground and air electromagnetics under the same rotation axis are processed to obtain the attitude error of the three-component coil magnetic sensor corresponding to different transmitting frequency points under the same rotation axis.

10. The method for evaluating the motion attitude error of ground-to-space frequency-domain electromagnetic detection coil according to claim 9, characterized in that: Process the three-component magnetic field data of the ground and air under the same rotation axis to obtain the attitude error of the three-component coil magnetic sensor corresponding to different transmission frequency points under the same rotation axis, including: Calculate the amplitude and phase of the signal frequency domain components at different transmission frequency points; The absolute attitude error of the magnetic field amplitude under static deflection is obtained by subtracting the amplitude of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection from the amplitude of the signal frequency domain component of the initial attitude angle, and the relative attitude error of the magnetic field amplitude under static deflection is obtained through the absolute attitude error of the magnetic field amplitude under static deflection; The phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the magnetic field phase attitude error under static deflection; The absolute attitude error of the magnetic field amplitude under periodic swing is obtained by subtracting the amplitude of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing from the amplitude of the signal frequency domain component of the initial attitude angle, and the relative attitude error of the magnetic field amplitude under periodic swing is obtained through the absolute attitude error of the magnetic field amplitude under periodic swing; The phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing is subtracted from the phase of the signal frequency domain component of the initial attitude angle to obtain the magnetic field phase attitude error under periodic swing.

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