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

Abstract

The present application belongs to the field of ground-to-space frequency-domain electromagnetic detection technology and relates to a ground-to-space frequency-domain electromagnetic detection coil motion attitude error assessment system and method, comprising: a motion execution unit, which drives a three-component coil magnetic sensor to perform static deflection or periodic oscillation; a three-component magnetic measurement unit, which is used to obtain ground-to-space electromagnetic three-component magnetic field data collected by the three-component coil magnetic sensor; a posture measurement unit, which is used to obtain the initial attitude angle, attitude angle after static deflection, and attitude angle during periodic oscillation of the three-component coil magnetic sensor; and a processor, which 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 oscillations based on the initial attitude angle, attitude angle after static deflection, attitude angle during periodic oscillation, and ground-to-space electromagnetic three-component magnetic field data. This system can quantitatively study the interference of static deflection and periodic oscillation amplitude and frequency parameters on electromagnetic data.

Description

Technical Field

[0001] The present application belongs to the field of ground-to-space frequency domain electromagnetic detection technology, and relates to a ground-to-space frequency domain electromagnetic detection coil motion attitude error evaluation system and method. Background Art

[0002] As a geophysical exploration method, the ground-to-air frequency domain electromagnetic method can achieve fine detection of underground structures at large depths. The ground-to-air frequency domain electromagnetic method arranges an artificial field source on the ground and transmits 2 n Using a pseudo-random waveform sequence, a drone-mounted electromagnetic detection coil is used to collect magnetic field data in the air. However, the receiving coil is easily affected by the drone's flight state and airborne turbulence, resulting in unstable measurements during flight. It often exhibits two types of motion: periodic low-frequency oscillations caused by changes in the drone's flight state, and high-frequency vibrations caused by airborne turbulence. The motion of the receiving coil inevitably cuts through the geomagnetic flux lines, resulting in significant low-frequency motion noise in the magnetic field data. This swamps the valid target frequency signal, affecting the accuracy of the detection results and limiting the deep exploration capabilities of the ground-to-air frequency domain electromagnetic system. Therefore, evaluating the motion error of the ground-to-air frequency electromagnetic detection coil is of great significance.

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

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

[0005] This application is implemented in this way.

[0006] A first aspect of an embodiment of the present application provides a ground-to-space frequency-domain electromagnetic detection coil motion attitude error assessment system, comprising:

[0007] A motion execution unit, used for driving the three-component coil magnetic sensor to perform static deflection or periodic swing;

[0008] 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 the received signal excited by the transmitting signal of the transmitting system;

[0009] An attitude measurement unit is used to obtain the initial attitude angle, attitude angle after static deflection, and attitude angle after periodic swing of the three-component coil magnetic sensor;

[0010] 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 based on the initial attitude angle, the attitude angle after static deflection, the attitude angle after periodic swing, and the three-component ground-air electromagnetic magnetic field data.

[0011] Furthermore, 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 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 rotating axes respectively.

[0012] Furthermore, 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.

[0013] Furthermore, 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.

[0014] Furthermore, the processor is further configured to obtain state information corresponding to a rotation instruction, the rotation instruction being an instruction from the motion execution unit to drive the three-component coil magnetic sensor to complete rotation, the state information including an initial attitude angle, an attitude angle after static deflection, and an attitude angle after periodic swing;

[0015] The state information of the same rotating shaft is associated with the ground-air electromagnetic three-component magnetic field data collected during 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;

[0016] By processing the three-component ground-air electromagnetic magnetic field data under the same rotation axis, the attitude error of the three-component coil magnetic sensor corresponding to different transmission frequency points under the same rotation axis is obtained.

[0017] Furthermore, the processing of the ground-air electromagnetic three-component magnetic field data under the same rotation axis to obtain the attitude errors of the three-component coil magnetic sensors corresponding to different emission frequency points under the same rotation axis includes:

[0018] Perform Fourier transform on the three-component electromagnetic magnetic field data of the ground and space to obtain the frequency domain components of the signals at different emission frequency points;

[0019] Calculate the amplitude and phase of the signal frequency domain components at different transmission frequency points;

[0020] 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;

[0021] The magnetic field phase attitude error under static deflection is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection from the phase of the signal frequency domain component of the initial attitude angle;

[0022] 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;

[0023] The magnetic field phase attitude error under periodic swing is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing from the phase of the signal frequency domain component of the initial attitude angle.

[0024] A second aspect of an embodiment of the present application provides a method for evaluating motion attitude errors of a ground-to-space frequency-domain electromagnetic detection coil, comprising:

[0025] Acquiring static deflection or periodic oscillation data, wherein the static deflection or periodic oscillation data is data corresponding to the static deflection or periodic oscillation of the three-component coil magnetic sensor;

[0026] Acquiring ground-to-air electromagnetic three-component magnetic field data collected by a three-component coil magnetic sensor, wherein the ground-to-air electromagnetic three-component magnetic field data is a received signal excited by a transmitting signal of a transmitting system;

[0027] Obtaining the initial attitude angle, attitude angle after static deflection, and attitude angle after periodic swing of the three-component coil magnetic sensor;

[0028] According to the initial attitude angle, the attitude angle after static deflection, the attitude angle after periodic swing, and the three-component electromagnetic magnetic field data of the ground and air, the magnetic field amplitude attitude error and magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflection or periodic swing are calculated.

[0029] Furthermore, 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, 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.

[0030] Furthermore, the state information of the same rotating shaft is associated with the ground-to-air electromagnetic three-component magnetic field data collected during a preset time period when the three-component coil magnetic sensor completes the rotation instruction, thereby obtaining 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;

[0031] The three-component ground-air electromagnetic magnetic field data under the same rotation axis are processed to obtain the attitude error of the three-component coil magnetic sensor corresponding to different transmission frequency points under the same rotation axis.

[0032] Furthermore, the three-component ground-air electromagnetic magnetic field data under the same rotation axis is processed to obtain the attitude errors of the three-component coil magnetic sensor corresponding to different emission frequency points under the same rotation axis, including:

[0033] Calculate the amplitude and phase of the signal frequency domain components at different transmission frequency points;

[0034] 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;

[0035] The magnetic field phase attitude error under static deflection is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection from the phase of the signal frequency domain component of the initial attitude angle;

[0036] 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;

[0037] The magnetic field phase attitude error under periodic swing is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing from the phase of the signal frequency domain component of the initial attitude angle.

[0038] Compared with the prior art, the system or method of this application has at least the following beneficial effects:

[0039] An embodiment of the present application provides a ground-to-space frequency domain electromagnetic detection coil motion attitude error assessment system, which realizes the attitude change of a three-component coil magnetic sensor by deploying a motion execution unit on the ground. It can quantitatively study the interference of static deflection and periodic swing amplitude and frequency parameters on electromagnetic data, and can efficiently evaluate the attitude error of the three-component coil magnetic sensor movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a structural block diagram of a ground-to-space frequency-domain electromagnetic detection coil motion attitude error assessment system provided in an embodiment of the present application;

[0041] Figure 2 A schematic diagram of the mechanical structure of a ground-to-space frequency-domain electromagnetic detection coil motion attitude error assessment system provided in an embodiment of the present application;

[0042] Figure 3 A flow chart of a method for evaluating the motion attitude error of a ground-to-space frequency-domain electromagnetic detection coil provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0044] In order to achieve quantitative measurement of the attitude error of the three-component coil magnetic sensor, a controllable method is adopted to control the relevant motion parameters of static deflection and periodic swing to achieve 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 deflection or periodic swing.

[0045] In an embodiment of the present application, the three-component coil magnetic sensor is composed of three groups of mutually orthogonal coils, which are used to measure the three orthogonal components of the magnetic field, and each coil receives the magnetic field signal in the corresponding direction. The study of the attitude error of the three-component coil magnetic sensor carried by the drone can optimize the physical structure design of the three-component coil magnetic sensor, such as the size, shape, number of turns and relative position of the coils, by analyzing the influence of the attitude deviation on the measurement results. For example, the optimal relative position of the three-component coil magnetic sensor is determined to reduce the influence of mutual inductance. It helps to design a more suitable preamplifier 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, the optimal damping coefficient adjustment range can be determined.

[0046] Research on attitude error evaluation methods can provide theoretical support for attitude error correction, and can enable three-component coil magnetic sensors to obtain accurate measurement results in complex environments (such as mountainous areas, canyons, lakes, etc.), thereby expanding their application scope.

[0047] To achieve the above purpose, see Figure 1As shown, the embodiment of the present application provides a ground-to-air frequency domain electromagnetic detection coil motion attitude error assessment system. The entire system is set on the ground. Here, the ground setting means dynamic flight relative to the air, and is stationary relative to the ground. For example, it can be fixed on a laboratory table on the ground, or it can be directly fixed on the ground, and it can be outdoors or indoors. It includes:

[0048] The motion execution unit 101 is used to drive the three-component coil magnetic sensor to perform static deflection or periodic swing;

[0049] It is understood that the motion execution unit 101 includes a motor drive structure and a three-component coil magnetic sensor fixed structure. The motor drive structure drives the three-component coil magnetic sensor to generate a static deflection of a certain angle or a dynamic periodic oscillation of a certain amplitude and frequency according to a given instruction. By changing the connection direction of the three-component coil magnetic sensor and the motion execution unit 101, the three-component coil magnetic sensor can produce different posture change modes, such as static pitch angle deflection, periodic pitch angle oscillation, static roll angle deflection, and periodic roll angle oscillation.

[0050] The motion execution unit 101 can set the angle of static deflection and the amplitude and frequency of periodic oscillation 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.

[0051] The three-component magnetic measurement unit 102 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 the received signal excited by the transmission signal of the transmission system;

[0052] The transmitting system sends electromagnetic excitation signals of specific frequencies into the ground via a long grounded wire or transmitting coil. As these signals propagate underground, they interact with the subsurface medium, generating an induced electromagnetic field. The transmitting system can output electromagnetic signals at multiple frequencies, typically ranging from low to high. This multi-frequency transmission method adapts to varying geological conditions and detection depth requirements. The transmitting system supports a variety of waveforms, such as square waves and pseudo-random waves. Different waveforms are suitable for different detection scenarios. For example, pseudo-random waves can improve the signal's anti-interference ability.

[0053] The ground-to-air electromagnetic three-component magnetic field data is the received signal collected by the three-component coil magnetic sensor under the excitation of the transmitting signal of the transmitting system.

[0054] The input of the three-component magnetic measurement unit 102 is connected to the three-component coil magnetic sensor to record the ground-to-air electromagnetic three-component magnetic field data 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 via wired or wireless means for the input ground-to-air electromagnetic three-component magnetic field data, as well as circuits for realizing the said functions.

[0055] The attitude measurement unit 103 is used to obtain the initial attitude angle, the attitude angle after static deflection, and the attitude angle after periodic swing of the three-component coil magnetic sensor;

[0056] The attitude measurement unit 103 is linked to and fixed to the three-component magnetic coil sensor. The attitude measurement unit 103 may include a three-axis accelerometer for measuring the acceleration of the three-component magnetic coil sensor in three orthogonal directions. By detecting the components of gravitational acceleration in different directions, the pitch and roll angles of the three-component magnetic coil sensor can be calculated. A three-axis gyroscope may also be included for measuring the angular velocity of the three-component magnetic coil sensor about its rotation axis. By integrating the angular velocity, the real-time attitude angle of the three-component magnetic coil sensor can be obtained.

[0057] 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 at different static deflection angles or periodic oscillation based on the initial attitude angle, the attitude angle after static deflection, the attitude angle during periodic oscillation, and the three-component ground-to-air electromagnetic magnetic field data. Processor 104 is an electronic device with computing capabilities, including the function of transmitting data via wired or wireless means and the circuitry for implementing such functions. Processor 104 receives the ground-to-air electromagnetic three-component magnetic field data from the three-component magnetic measurement unit 102, receives the initial attitude angle, the attitude angle after static deflection, and the attitude angle during periodic oscillation of the three-component coil magnetic sensor obtained by the attitude measurement unit 103, and receives the static deflection angle and the amplitude and frequency of periodic oscillation set by the motion execution unit 101.

[0058] The processor 104 can also input the axis number of the three-component coil magnetic sensor corresponding to the current detection. Based on the initial attitude angle, the attitude angle after static deflection, the attitude angle after periodic swing, and the three-component ground-to-air electromagnetic magnetic field data, 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 swings are calculated, including, for example, the magnetic field amplitude attitude error and magnetic field phase attitude error under 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. The magnetic field amplitude attitude error includes the absolute magnetic field amplitude attitude error and the relative magnetic field amplitude attitude error.

[0059] Based on the three-component ground-to-air electromagnetic magnetic field data at the initial attitude angle, the amplitude and phase of the signal frequency domain component corresponding to each coil component at each transmission frequency point at the initial attitude angle are calculated; the coil component here refers to a coil that constitutes the three-component coil magnetic sensor.

[0060] 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 at the initial attitude angle. 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 transmission frequencies, 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 are obtained for each coil component at different transmission frequencies.

[0061] The magnetic field phase attitude error under static deflection is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection from the phase of the signal frequency domain component of the initial attitude angle; by calculating at different transmission frequencies, the magnetic field phase attitude error of each coil component under static deflection at different transmission frequencies is obtained.

[0062] 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;

[0063] The magnetic field phase attitude error under periodic swing is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing from the phase of the signal frequency domain component of the initial attitude angle;

[0064] In one embodiment, a three-component magnetic coil sensor establishes two-dimensional coordinate axes in a horizontal plane with its geometric center as the coordinate origin. The drive shaft of the motion execution unit 101 is sequentially coaxially arranged with one of the two perpendicular coordinate axes, causing the three-component magnetic coil sensor to rotate about each of the two rotation axes. The two perpendicular coordinate axes are arbitrary, and their relative orientation to the three coils of the three-component magnetic coil sensor is not required. To facilitate mounting and fixing the sensor to the motion execution unit 101, a mounting structure can be provided on the housing of the three-component magnetic coil sensor to secure it to the drive shaft of the motion execution unit 101. The mounting structure can be a mounting hole, a clip that docks and secures the sensor to the drive shaft, or the like. This is not limiting. Once fixed, the sensor can be easily disassembled and reoriented, or the two coordinate axes can be automatically interchanged to be coaxial with the drive shaft. The two perpendicular coordinate axes are not front-to-back. The drive shaft of the motion execution unit 101 can arbitrarily coaxially select one of the coordinate axes and then the other. This allows one of the coordinate axes to serve as the rotation axis for simulating pitch angle, and the other to serve as the rotation axis for simulating roll angle.

[0065] In one embodiment, the processor 104 is further configured to obtain state information corresponding to a rotation instruction, the rotation instruction being an instruction from the motion execution unit 101 to drive the three-component coil magnetic sensor to complete rotation, the state information including an initial attitude angle, an attitude angle after static deflection, and an attitude angle after periodic swing;

[0066] Processor 104 can obtain state information corresponding to a rotation instruction based on a rotation instruction for the three-component coil magnetic sensor to perform static deflection or periodic oscillation, executed by motion execution unit 101. The rotation instruction indicates whether the three-component coil magnetic sensor is to perform static deflection or periodic oscillation, as well as the angle of static deflection and the amplitude and frequency of periodic oscillation. The rotation instruction only indicates preset rotation parameters of the three-component coil magnetic sensor. When no rotation instruction is given, the three-component coil magnetic sensor is in a static state.

[0067] The state 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 state 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 obtained by the attitude measurement unit 103.

[0068] In one embodiment, the state information of the same rotating shaft is associated with the ground-to-air electromagnetic three-component magnetic field data collected during a preset time period after the three-component coil magnetic sensor completes the rotation instruction, thereby obtaining the ground-to-air electromagnetic three-component magnetic field data corresponding to different state information of the same rotating shaft;

[0069] It can be understood that, through association, when the state of the initial attitude angle is obtained, the three-component ground-to-air electromagnetic three-component magnetic field data collected by the three-component magnetic measurement unit 102; when the state of the attitude angle after static deflection is obtained, the three-component ground-to-air electromagnetic three-component magnetic field data collected by the three-component magnetic measurement unit 102; and when the state of the periodically swinging attitude angle is obtained, the three-component ground-to-air electromagnetic three-component magnetic field data collected by the three-component magnetic measurement unit 102.

[0070] 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 disturbed by external interference and moving. At this time, the transmitting system transmits 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 it can be integrated into the processor 104, with the processor 104 as the host to control 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 transmitting system, the processor 104 also needs to be provided with a GPS synchronization module for synchronizing the transmitting system to obtain the startup and shutdown time of the transmitting signal. A GPS synchronization module is provided inside the three-component magnetic measurement unit 102, a GPS synchronization module is provided in the attitude measurement unit 103, and a GPS synchronization module is provided in the transmitting system, for a total of three GPS synchronization modules, to achieve synchronization of the magnetic field signal, attitude, and transmitting current.

[0071] Therefore, in one embodiment, the processor 104 is further configured to control the timing of starting and shutting down the motion execution unit 101, the three-component magnetic measurement unit 102, and the attitude measurement unit 103, and to synchronize the transmission system via the GPS synchronization module. Furthermore, the processor 104 receives data from the motion execution unit 101, the three-component magnetic measurement unit 102, and the attitude measurement unit 103.

[0072] In one embodiment, the processor 104 processes the three-component ground-air electromagnetic magnetic field data under the same rotation axis to obtain the attitude errors of the three-component coil magnetic sensor corresponding to different transmission signal frequency points under the same rotation axis.

[0073] The three-component coil magnetic sensor rotates around two coordinate axes, simulating pitch angle changes through one axis and rolling angle changes through the other axis.

[0074] For the same rotating axis, at least one static deflection and periodic swing are required, and during the static deflection and periodic swing, the three-component ground-to-air electromagnetic 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, the processor 104 processes the data to obtain the magnetic field amplitude attitude error and the magnetic field phase attitude error during the static deflection or periodic swing under the same rotating axis.

[0075] In one embodiment, Fourier transform is performed on the three-component ground-to-air electromagnetic magnetic field data to obtain frequency domain components of signals at multiple different transmission frequency points;

[0076] Calculate the amplitude and phase of the signal frequency domain components at different transmission frequency points;

[0077] 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;

[0078] The magnetic field phase attitude error under static deflection is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection from the phase of the signal frequency domain component of the initial attitude angle;

[0079] 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;

[0080] The magnetic field phase attitude error under periodic swing is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing from the phase of the signal frequency domain component of the initial attitude angle.

[0081] Because the transmitted signal contains multiple transmission frequencies, attitude errors affect the received signal differently at different transmission frequencies. By performing a Fourier transform on the three-component ground-to-air electromagnetic magnetic field data, we obtain the frequency domain components of the signals at multiple different transmission frequencies, and calculate the attitude error for each transmission frequency.

[0082] The following is an implementable structure for realizing the above-mentioned ground-to-air frequency domain electromagnetic detection coil motion attitude error evaluation system. Figure 2 The following is a schematic diagram of the mechanical structure of a ground-to-space frequency domain electromagnetic detection coil motion attitude error assessment system provided by an embodiment of the present application. It includes:

[0083] The motion execution unit 101 includes: a servo motor 201, a programmable logic controller 202, and a motor driver 203, wherein: the servo motor 201 performs static deflection or periodic swing according to given parameters, the programmable logic controller is used to store and execute the operation program of the servo motor 201, and send the motor control signal to the motor driver 203. The motor driver 203 is responsible for converting the control signal into the operating current of the servo motor 201. The programmable logic controller 202 has a built-in transmission module for communicating with the processor 104.

[0084] The three-component magnetic measurement unit 102 uses a coil receiver 209 to measure and record the three-component ground-air electromagnetic magnetic field data, and also has a communication module to communicate with the processor 104.

[0085] The attitude measurement unit 103 includes an attitude measurement sensor 210, a battery 211, and an attitude data recorder 212. The battery 211 provides 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 about its axis of rotation. By integrating the angular velocity, the real-time attitude angle of the three-component coil magnetic sensor is obtained. This is then transmitted to the processor 104 via the attitude data recorder 212 and the communication module.

[0086] The mechanical support structure, including a base 204, brackets 205, a drive shaft 206, and bearings 207, supports the servo motor 201 and the three-component coil magnetic sensor, ensuring that the servo motor can drive the three-component coil magnetic sensor to operate smoothly and reducing friction during rotation. The base 204 is placed on the ground or a laboratory bench. Three parallel brackets 205 are provided on the base 204 to secure the servo motor 201 and the servo motor's drive shaft 206. Bearings 207 are located on the tops of two of the brackets 205 to reduce friction. The programmable logic controller 202, motor driver 203, and coil receiver 209 are all mounted on the base 204.

[0087] After the base 204 is placed on the horizontal ground, the bottom of each bracket 205 is connected to the base 204 through 6 fastening screws, and the top is connected to the transmission shaft 206 through the 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.

[0088] The three-component coil magnetic sensor is housed within a housing 208. Circular holes of equal diameter to the drive shaft 206 are located in the center of each of the four sides of the housing 208. Drive shaft 206 passes through the center and transmits torque via an A-type flat key. The three-component coil magnetic sensor and drive shaft 206 are supported by a bracket 205. The three-axis induced electromotive force output by the three-component coil magnetic sensor is recorded by a coil receiver 209.

[0089] The attitude measurement sensor 210 , the battery 211 and the attitude data recorder 212 are all mounted on a mounting plate provided on the top surface of the three-component coil magnetic sensor housing 208 .

[0090] In one embodiment, the present application also provides a method for evaluating the motion attitude error of a ground-to-space frequency domain electromagnetic detection coil. The content can be used for corresponding explanations with reference to the ground-to-space frequency domain electromagnetic detection coil motion attitude error evaluation system. Figure 3 The flowchart of a method for evaluating the motion attitude error of a ground-to-space frequency-domain electromagnetic detection coil is shown, comprising:

[0091] S301 acquires static deflection or periodic oscillation data, where the static deflection or periodic oscillation data is data corresponding to the static deflection or periodic oscillation of the three-component coil magnetic sensor;

[0092] S302: Acquiring ground-to-air electromagnetic three-component magnetic field data collected by a three-component coil magnetic sensor, wherein the ground-to-air electromagnetic three-component magnetic field data is a received signal excited by a transmission signal of a transmitting system;

[0093] S303: acquiring the initial attitude angle, static deflection attitude angle, and periodic swing attitude angle of the three-component coil magnetic sensor;

[0094] S304 calculates the magnetic field amplitude attitude error and magnetic field phase attitude error of the three-component coil magnetic sensor under static deflection or periodic swing based on the initial attitude angle, the attitude angle after static deflection, the attitude angle after periodic swing, and the three-component ground-air electromagnetic magnetic field data.

[0095] In one embodiment, a three-component coil magnetic sensor establishes a two-dimensional coordinate axis in a horizontal plane with its geometric center as the coordinate origin, so that the three-component coil magnetic sensor rotates with two coordinate axes as rotation axes. By rotating around one of the rotation axes, a pitch angle change is simulated, and the other rotation axis simulates a roll angle change.

[0096] In one embodiment, state information of the same rotating shaft is correlated with ground-to-air electromagnetic three-component magnetic field data collected during a preset time period after the three-component coil magnetic sensor completes a rotation instruction, thereby obtaining ground-to-air electromagnetic three-component magnetic field data corresponding to different state information of the same rotating shaft; the state information includes an initial attitude angle, a static deflection attitude angle, and a periodic oscillation attitude angle;

[0097] In one embodiment, processing 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 transmission signal frequency points under the same rotation axis includes:

[0098] Perform Fourier transform on the three-component electromagnetic magnetic field data of the ground and space to obtain the frequency domain components of the signals at multiple different emission frequency points;

[0099] Calculate the amplitude and phase of the signal frequency domain components at different transmission frequency points;

[0100] 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;

[0101] The magnetic field phase attitude error under static deflection is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection from the phase of the signal frequency domain component of the initial attitude angle;

[0102] 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;

[0103] The magnetic field phase attitude error under periodic swing is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing from the phase of the signal frequency domain component of the initial attitude angle;

[0104] The embodiment of the present application is explained with reference to a specific process. A method for evaluating the motion attitude error of a ground-to-air frequency-domain electromagnetic detection coil includes:

[0105] Calibrate the first initial attitude angle with reference to the North Celestial East coordinate system . 、 、 They are the first initial angles of the three-component coil magnetic sensor. The first initial attitude angle and the first in the first initial angle are used to distinguish them from the initial attitude angle of the other shaft. The ground-air electromagnetic three-component magnetic field data measured by the three-component coil magnetic sensor at the first initial attitude angle are recorded. , Represents the three orthogonal directions.

[0106] Static deflection at a certain pitch angle Under the condition of , the three-component coil magnetic sensor has a static deflection of the pitch angle. The attitude angle after the static deflection of the three-component coil magnetic sensor is measured as Record the three-component magnetic field data of the ground and air electromagnetic measured by the three-component coil magnetic sensor under the static deflection of the pitch angle at this time , Represents the three orthogonal directions.

[0107] Output pitch angle periodic swing, swing amplitude The magnitude of the static deflection of the pitch angle is consistent with the swing frequency. The three-component coil magnetic sensor undergoes a periodic pitch angle swing, and the attitude angle of the three-component coil magnetic sensor is measured. . is the time, and the three-component magnetic field data of the ground and air electromagnetic measured by the three-component coil magnetic sensor under the periodic swing of the pitch angle is recorded at this time. .

[0108] Remove the three-component coil magnetic sensor from the shaft and install it in the other direction. Calibrate the second initial attitude angle of the three-component coil magnetic sensor . They are the second initial angles of the three coils in the three-component coil magnetic sensor, and record the ground-air electromagnetic three-component magnetic field data measured by the three-component coil magnetic sensor at the second initial attitude angle. .

[0109] At a static deflection Under the condition of static deflection of the roll angle of the three-component coil magnetic sensor, the attitude angle after static deflection of the roll angle of the three-component coil magnetic sensor is measured. Record the three-component magnetic field data of the ground and air electromagnetic measured by the three-component coil magnetic sensor under the static deflection of the roll angle at this time .

[0110] The output swings periodically, with an amplitude of , consistent with the static deflection, the swing frequency is The three-component coil magnetic sensor undergoes periodic roll angle swing, and the attitude angle of the three-component coil magnetic sensor under the periodic roll angle swing is measured. Record the three-component magnetic field data of the ground and air electromagnetic measured by the three-component coil magnetic sensor under the periodic swing of the roll angle .

[0111] The above 6 sets of ground-air electromagnetic three-component magnetic field data were measured respectively. Perform Fourier transform (FFT), assuming the signal to be analyzed is :

[0112] ,

[0113] Where, represents the result of Fourier transform, is the angular frequency of the signal transmitted by the transmitting system, , Represents the three-component electromagnetic magnetic field data of the earth and space.

[0114] Calculate the amplitude and phase of the frequency domain components of the signal of the three-component electromagnetic magnetic field data of the ground and space at each transmission frequency point:

[0115] ,

[0116] ,

[0117] 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.

[0118] For static deflection of pitch angle In the case of static deflection of the pitch angle, the absolute attitude error of the magnetic field amplitude , Indicates the The amplitude of the pitch angle static deflection of the coil component, Indicates the The amplitude of the coil component at the first initial attitude angle, the magnetic field amplitude relative to the attitude error under the static deflection of the pitch angle , magnetic field phase attitude error under static deflection of pitch angle , Indicates the The phase of the pitch angle of each coil component under static deflection, Indicates the The phase of the coil components at the first initial attitude angle.

[0119] For the periodic swing of pitch angle In the case of periodic swing of pitch angle, the absolute attitude error of magnetic field amplitude is , To indicate the The amplitude of the pitch angle of each coil component under periodic swing, the relative attitude error of the magnetic field amplitude under periodic swing of the pitch angle , magnetic field phase attitude error under periodic pitch angle swing , Indicates the The phase of the pitch angle of each coil component under periodic swing.

[0120] For static deflection of roll angle In the case of static deflection of the roll angle, the absolute attitude error of the magnetic field amplitude is , For the The amplitude of the coil component at the second initial attitude angle, No. The amplitude of the roll angle of each coil component under static deflection, the magnetic field amplitude under static deflection of the roll angle relative to the attitude error , magnetic field phase attitude error under static deflection of roll angle , Indicates the The phase of the roll angle of each coil component under static deflection, Indicates the The phase of the coil component at the second initial attitude angle.

[0121] For the periodic oscillation of the roll angle In the case of periodic swing of the roll angle, the absolute attitude error of the magnetic field amplitude is , No. The amplitude of the roll angle of each coil component under periodic swing, the magnetic field amplitude under periodic swing of the roll angle relative attitude error , magnetic field phase attitude error under periodic swing of roll angle , Indicates the The phase of the roll angle of each coil component under periodic swing.

[0122] This completes the evaluation of attitude errors under static deflection and periodic oscillation. By setting a series of static deflections and performing attitude error evaluations separately, we can plot the absolute (relative) attitude error and magnetic field phase error of the three-component coil magnetic sensor under static deflection.

[0123] By setting a series of periodic swing amplitudes, the attitude error can be evaluated separately. The curves of the absolute (relative) attitude error of the magnetic field amplitude and the magnetic field phase attitude error under the periodic swing amplitude of the three-component coil magnetic sensor can be drawn.

[0124] It is also possible to set a series of periodic swing frequencies to evaluate the attitude errors separately, and then plot 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.

[0125] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A ground-to-air 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 the received signal excited by the transmitting signal of the transmitting system; An attitude measurement unit is used to obtain the initial attitude angle, attitude angle after static deflection, and attitude angle after 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 based on the initial attitude angle, the attitude angle after static deflection, the attitude angle after periodic swing, and the three-component ground-air electromagnetic magnetic field data; The processor is further configured to obtain state information corresponding to a rotation instruction, the rotation instruction being an instruction from the motion execution unit to drive the three-component coil magnetic sensor to complete rotation, the state information including an initial attitude angle, an attitude angle after static deflection, and an 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 during 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 ground-air electromagnetic magnetic field data under the same rotation axis, the attitude errors of the three-component coil magnetic sensor corresponding to different emission frequency points under the same rotation axis are obtained, including: Perform Fourier transform on the three-component electromagnetic magnetic field data of the ground and space to obtain the frequency domain components of the signals at different emission 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 magnetic field phase attitude error under static deflection is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection from the phase of the signal frequency domain component of the initial attitude angle; 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 magnetic field phase attitude error under periodic swing is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing from the phase of the signal frequency domain component of the initial attitude angle.

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 during initial attitude angle, static deflection and periodic swing.

5. A method for evaluating the motion attitude error of a ground-to-air frequency-domain electromagnetic detection coil, characterized in that: include: Acquiring static deflection or periodic oscillation data, wherein the static deflection or periodic oscillation data is data corresponding to the static deflection or periodic oscillation of the three-component coil magnetic sensor; Acquiring ground-to-air electromagnetic three-component magnetic field data collected by a three-component coil magnetic sensor, wherein the ground-to-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 after periodic swing of the three-component coil magnetic sensor; Based on the initial attitude angle, the attitude angle after static deflection, the attitude angle after periodic swing, and the three-component electromagnetic magnetic field data of the ground and air, the magnetic field amplitude attitude error and magnetic field phase attitude error of the three-component coil magnetic sensor under different static deflection or periodic swing are calculated; Correlating state information of the same rotating shaft with ground-to-air electromagnetic three-component magnetic field data collected during a preset time period after the three-component coil magnetic sensor completes a rotation instruction, thereby obtaining ground-to-air electromagnetic three-component magnetic field data corresponding to different state information of the same rotating shaft; the state information includes an initial attitude angle, an attitude angle after static deflection, and an attitude angle after periodic swing; Process the three-component ground-air electromagnetic 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, 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 magnetic field phase attitude error under static deflection is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under static deflection from the phase of the signal frequency domain component of the initial attitude angle; 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 magnetic field phase attitude error under periodic swing is obtained by subtracting the phase of the signal frequency domain component of the same coil component at the same transmission frequency point under periodic swing from the phase of the signal frequency domain component of the initial attitude angle.

6. The method for evaluating the motion attitude error of a ground-to-space frequency-domain electromagnetic detection coil according to claim 5, 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. 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.

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