Inter-axis coupling suppression method and apparatus

Abstract

The application relates to an inter-axis coupling suppression method and device, wherein the inter-axis coupling suppression method comprises the following steps: after a preset high-frequency modulation field is applied to a first measurement axis and a second measurement axis of an atomic magnetometer, a first excitation strategy and a second excitation strategy of the atomic magnetometer are independently executed respectively, and execution results of the excitation strategies are analyzed to obtain a first frequency response and a second frequency response; a coupling matrix is determined based on the first frequency response and the second frequency response; a decoupling filter matrix corresponding to the coupling matrix is determined and is converted into time-domain filter coefficients; when the atomic magnetometer performs actual double-axis measurement, a first actual measurement signal corresponding to the first measurement axis and a second actual measurement signal corresponding to the second measurement axis are acquired in real time, and the first actual measurement signal and the second actual measurement signal are decoupled based on the time-domain filter coefficients to obtain a first decoupled signal and a second decoupled signal. Through the application, the problem that the measurement accuracy of the magnetometer is low is solved.

Description

Technical Field

[0001] This application relates to the field of digital signal processing, and in particular to methods and apparatus for suppressing inter-axis coupling. Background Technology

[0002] Biaxial spin-free exchange relaxation (SERF) atomic magnetometers, with their ultra-high sensitivity, possess irreplaceable application value in key fields such as biomagnetic imaging (e.g., magnetoencephalography, magnetocardiography), geophysical exploration, and fundamental physics research. Their core advantage lies in their ability to achieve high-precision synchronous measurement of biaxial magnetic field signals. However, in practical engineering applications, due to inherent coupling characteristics of atomic spin dynamics, non-orthogonal arrangement errors of the optical and magnetic fields, and mechanical alignment deviations of the triaxial magnetic coils, the magnetic field signals of the two measurement axes are highly susceptible to crosstalk, leading to distorted measurement results and severely limiting the accuracy of magnetic field positioning and signal resolution.

[0003] In related technologies, methods that typically rely on hardware alignment optimization or simple proportional correction are difficult to adapt to complex time-varying system responses, resulting in low measurement accuracy of biaxial SERF magnetometers.

[0004] Currently, there is no effective solution to the low measurement accuracy of biaxial SERF magnetometers in related technologies. Summary of the Invention

[0005] This application provides an interaxial coupling suppression method and apparatus to at least solve the problem of low measurement accuracy of biaxial SERF magnetometers in related technologies.

[0006] In a first aspect, embodiments of this application provide an inter-coupling suppression method, the method comprising:

[0007] After applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, a first excitation strategy and a second excitation strategy for the atomic magnetometer are executed independently, and the execution results of the excitation strategies are analyzed to obtain a first frequency response corresponding to the first excitation strategy and a second frequency response corresponding to the second excitation strategy. The frequency response includes the frequency response of the measurement axis itself and the coupling response between the measurement axes. The first excitation strategy is used to indicate that only the first magnetic field excitation is applied to the first measurement axis; the second excitation strategy is used to indicate that only the second magnetic field excitation is applied to the second measurement axis.

[0008] Based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy, the corresponding coupling matrix is ​​determined;

[0009] Determine the decoupling filter matrix corresponding to the coupling matrix, and transform the decoupling filter matrix into the corresponding time-domain filter coefficients;

[0010] When the atomic magnetometer performs actual biaxial measurement based on the preset high-frequency modulation field, it acquires the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis in real time, and decouples the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis based on the time-domain filter coefficients to obtain the first decoupled signal corresponding to the first measurement axis and the second decoupled signal corresponding to the second measurement axis.

[0011] In some embodiments, determining the decoupling filter matrix corresponding to the coupling matrix includes:

[0012] The decoupling filter matrix is ​​obtained by inverting the coupling matrix.

[0013] In some embodiments, after applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, the first and second excitation strategies for the atomic magnetometer are executed independently, respectively, including:

[0014] After applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, a first magnetic field excitation is applied to the first measurement axis while keeping the excitation of the second measurement axis at zero, thus obtaining the execution result of the first excitation strategy; a second magnetic field excitation is applied to the second measurement axis while keeping the excitation of the first measurement axis at zero, thus obtaining the execution result of the second excitation strategy.

[0015] In some embodiments, determining the corresponding coupling matrix based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy includes:

[0016] Based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy, the corresponding initial coupling matrix is ​​determined;

[0017] Based on the self-response signal of the first measurement axis in the execution result of the first excitation strategy and the coupling signal of the first measurement axis in the execution result of the second excitation strategy, the first correlation coefficient is calculated;

[0018] Based on the second measurement axis self-response signal in the execution result of the second excitation strategy and the second measurement axis coupling signal in the execution result of the first excitation strategy, a second correlation coefficient is calculated;

[0019] Based on the first correlation coefficient and the second correlation coefficient, the initial coupling matrix is ​​corrected to obtain the coupling matrix.

[0020] In some embodiments, analyzing the execution results of the incentive strategy to obtain a first frequency response corresponding to the first incentive strategy and a second frequency response corresponding to the second incentive strategy includes:

[0021] The execution result of the first excitation strategy is analyzed to obtain the frequency autoresponse function of the first measurement axis and the coupled frequency response function of the second measurement axis. Based on the frequency autoresponse function of the first measurement axis and the coupled frequency response function of the second measurement axis, the first frequency response corresponding to the first excitation strategy is obtained.

[0022] The execution results of the second excitation strategy are analyzed to obtain the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis. Based on the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis, the second frequency response corresponding to the second excitation strategy is obtained.

[0023] In some embodiments, the execution result of the first excitation strategy includes a first measurement axis self-response signal corresponding to the first measurement axis and a second measurement axis coupling signal corresponding to the second measurement axis;

[0024] The analysis of the execution result of the first excitation strategy to obtain the frequency self-response function of the first measurement axis and the coupled frequency response function of the second measurement axis includes:

[0025] Fourier transforms are performed on the first magnetic field excitation, the first measurement axis self-response signal, and the second measurement axis coupling signal to obtain the first frequency domain magnetic field excitation corresponding to the first magnetic field excitation, the first measurement axis frequency domain self-response signal corresponding to the first measurement axis self-response signal, and the second measurement axis frequency domain coupling signal corresponding to the second measurement axis coupling signal.

[0026] Based on the first frequency domain magnetic field excitation and the first measurement axis frequency domain self-response signal, the frequency self-response function of the first measurement axis is obtained;

[0027] Based on the first frequency domain magnetic field excitation and the second measurement axis frequency domain coupling signal, the coupling frequency response function of the second measurement axis is obtained.

[0028] In some embodiments, the execution result of the second excitation strategy includes the second measurement axis self-response signal corresponding to the second measurement axis and the first measurement axis coupling signal corresponding to the first measurement axis;

[0029] The analysis of the execution result of the second excitation strategy to obtain the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis includes:

[0030] Fourier transforms are performed on the second magnetic field excitation, the second measurement axis self-response signal, and the first measurement axis coupling signal to obtain the second frequency domain magnetic field excitation corresponding to the second magnetic field excitation, the second measurement axis frequency domain self-response signal corresponding to the second measurement axis self-response signal, and the first measurement axis frequency domain coupling signal corresponding to the first measurement axis coupling signal.

[0031] Based on the second frequency domain magnetic field excitation and the second measurement axis frequency domain self-response signal, the frequency self-response function of the second measurement axis is obtained;

[0032] Based on the second frequency domain magnetic field excitation and the first measurement axis frequency domain coupling signal, the coupling frequency response function of the first measurement axis is obtained.

[0033] In some embodiments, the decoupling process performed on the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis based on the time-domain filter coefficients to obtain the first decoupled signal corresponding to the first measurement axis and the second decoupled signal corresponding to the second measurement axis includes:

[0034] Based on the time-domain filter coefficients, a convolution operation is performed on the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis to obtain a first decoupled signal corresponding to the first measurement axis and a second decoupled signal corresponding to the second measurement axis.

[0035] In some embodiments, both the first magnetic field excitation and the second magnetic field excitation are either white noise or a linear frequency modulated signal.

[0036] Secondly, embodiments of this application provide an inter-axis coupling suppression device, the device comprising:

[0037] The response identification module is used to independently execute a first excitation strategy and a second excitation strategy for the atomic magnetometer after applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, and analyze the execution results of the excitation strategies to obtain a first frequency response corresponding to the first excitation strategy and a second frequency response corresponding to the second excitation strategy. The frequency response includes the frequency response of the measurement axis itself and the coupling response between the measurement axes. The first excitation strategy is used to indicate that only the first magnetic field excitation is applied to the first measurement axis; the second excitation strategy is used to indicate that only the second magnetic field excitation is applied to the second measurement axis. Based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy, the corresponding coupling matrix is ​​determined.

[0038] A time-domain filter coefficient generation module is used to determine the decoupling filter matrix corresponding to the coupling matrix and convert the decoupling filter matrix into the corresponding time-domain filter coefficients.

[0039] The real-time decoupling module is used to acquire, in real time, the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis when the atomic magnetometer performs actual dual-axis measurement based on the preset high-frequency modulation field, and to perform decoupling processing on the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis based on the time-domain filter coefficients to obtain the first decoupling signal corresponding to the first measurement axis and the second decoupling signal corresponding to the second measurement axis.

[0040] Compared to related technologies, the inter-axis coupling suppression method and apparatus provided in this application, after applying a preset high-frequency modulation field to the first and second measurement axes of an atomic magnetometer, independently execute a first excitation strategy and a second excitation strategy for the atomic magnetometer, and analyze the execution results of the excitation strategies to obtain a first frequency response corresponding to the first excitation strategy and a second frequency response corresponding to the second excitation strategy; the frequency response includes the frequency response of the measurement axis itself and the coupling response between the measurement axes; wherein, the first excitation strategy is used to indicate that only the first magnetic field excitation is applied to the first measurement axis; the second excitation strategy is used to indicate that only the second magnetic field excitation is applied to the second measurement axis; based on the first frequency response corresponding to the first excitation strategy... The system determines the coupling matrix by analyzing the second frequency response corresponding to the second excitation strategy, and then converts the decoupling filter matrix corresponding to the coupling matrix into the corresponding time-domain filter coefficients. During actual biaxial measurement using an atomic magnetometer based on a preset high-frequency modulation field, the system acquires the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis in real time. Based on the time-domain filter coefficients, the system decouples the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis to obtain the first decoupled signal corresponding to the first measurement axis and the second decoupled signal corresponding to the second measurement axis. This solves the problem of low measurement accuracy in biaxial SERF magnetometers in related technologies.

[0041] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0042] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0043] Figure 1 This is a hardware structure block diagram of a terminal for an inter-axis coupling suppression method according to an embodiment of this application;

[0044] Figure 2 This is a flowchart of an inter-axis coupling suppression method according to an embodiment of this application;

[0045] Figure 3 This is a comparison diagram of the coupling suppression of the second measurement axis to the first measurement axis before and after, according to an embodiment of this application;

[0046] Figure 4 This is a comparison diagram of the coupling suppression of the first measurement axis to the second measurement axis before and after, according to an embodiment of this application;

[0047] Figure 5This is a structural block diagram of an inter-axis coupling suppression device according to an embodiment of this application;

[0048] Figure 6 This is an experimental apparatus for a biaxial SERF atomic magnetometer according to an embodiment of this application;

[0049] Figure 7 This is a miniaturized biaxial SERF atomic magnetometer according to an embodiment of this application;

[0050] Figure 8 This is a schematic diagram of the overall process of the interaxial coupling suppression method according to an embodiment of this application. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application. Furthermore, it is understood that although the efforts made in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, modifications to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0052] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0053] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application means two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The terms “first,” “second,” “third,” etc., used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0054] The method embodiments provided in this example can be executed on a terminal, computer, or similar computing device. Taking running on a terminal as an example, Figure 1 This is a hardware structure block diagram of a terminal according to an embodiment of the inter-axis coupling suppression method of this application. Figure 1 As shown, a terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. Optionally, the terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the terminal described above. For example, the terminal may also include components that are larger than... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0055] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the inter-axis coupling suppression method in this embodiment. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thus implementing the aforementioned method. The memory 104 may include high-speed random access memory and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0056] The transmission device 106 is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by the terminal's communication provider. In one example, the transmission device 106 includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 106 may be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0057] This embodiment provides a method for suppressing inter-axis coupling. Figure 2 This is a flowchart of an inter-axis coupling suppression method according to an embodiment of this application, such as... Figure 2 As shown, the process includes the following steps:

[0058] Step S201: After applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, the first and second excitation strategies for the atomic magnetometer are executed independently, and the execution results of the excitation strategies are analyzed to obtain the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy. The frequency response includes the frequency response of the measurement axis itself and the coupling response between the measurement axes. The first excitation strategy is used to indicate that only the first magnetic field excitation is applied to the first measurement axis; the second excitation strategy is used to indicate that only the second magnetic field excitation is applied to the second measurement axis.

[0059] First, the dual-axis SERF atomic magnetometer experimental setup was started. A series of debugging operations were sequentially performed, including high-frequency non-magnetic electric heating and temperature closed-loop control of the alkali metal gas chamber, triaxial residual magnetic field compensation, application of preset high-frequency modulation fields for the first measurement axis (e.g., X-axis) and the second measurement axis (e.g., Z-axis), and dual-axis signal demodulation. This ensured the atomic magnetometer entered a stable working state, guaranteeing the normal operation of the basic hardware and signal link for dual-axis magnetic field measurement, and achieving synchronous output of the dual-axis magnetic field. The alkali metal atoms in the dual-axis SERF atomic magnetometer operate under the SERF mechanism. The evolution of the electron spin polarization P-dynamics of these alkali metal atoms under the influence of parameters such as magnetic and optical fields can be well described by the Bloch equation:

[0060] ;

[0061] in, Nuclear slowing factor; γ e = 2π×28 Hz / nT is the gyromagnetic ratio of a single electron; R is a vector magnetic field containing a triaxial magnetic field; op The optical pumping rate; This is the circular polarization vector of the photon; R is a unit quantity on the y-axis. rel Other relaxation rates besides the pump rate; is the time derivative of the electron spin polarization vector.

[0062] When high-frequency modulation fields of the same amplitude and frequency are applied simultaneously to the X-axis and Z-axis, i.e. , Based on the perturbation iteration method, the projection of the first harmonic term of the atomic spin polarization component along the direction of the circularly polarized pump light can be approximately expressed as:

[0063] ;

[0064] in, ; ; ; ; The reference frequency; J0 and J1 are the zeroth and first order Bessel functions, respectively; B x B y and B z R is the magnetic field component; op R is the optical pump rate. rel For relaxation rates other than pump rate; γ e = 2π×28 Hz / nT is the gyromagnetic ratio of a single electron; B m This represents the magnetic field amplitude.

[0065] With reference frequency Demodulating the corresponding magnetometer response signal, and distinguishing the phase along both axes, allows for the acquisition of the X-axis and Z-axis magnetic field information, thus enabling simultaneous dual-axis magnetic field measurement. In the above formula, the demodulated response signal for the X-axis can be expressed as: The demodulated response signal along the Z-axis can be expressed as: The demodulated response signal also shows that after applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, the presence of residual magnetic fields and non-orthogonal magnetic field projections in the system introduces inter-axis coupling, reducing the accuracy of dual-axis measurements. This is precisely the core motivation for conducting excitation strategy execution and frequency response analysis in this step.

[0066] After applying the preset high-frequency modulation fields to the first and second measurement axes of the atomic magnetometer, the first and second excitation strategies will be executed sequentially and independently. These two excitation strategies operate independently, reflecting the signal response state of the dual axes of the atomic magnetometer when a single measurement axis is excited, providing an independent and accurate experimental data basis for subsequent frequency response analysis. When executing the first excitation strategy, a preset first magnetic field excitation is applied only to the first measurement axis of the atomic magnetometer, while the excitation input to the second measurement axis remains zero, thus acquiring the complete signal response results of the dual axes under this excitation condition. When executing the second excitation strategy, a preset second magnetic field excitation is applied only to the second measurement axis, while the excitation input to the first measurement axis is set to zero, simultaneously acquiring the signal response results of the dual axes under this excitation condition. After independently executing the first and second excitation strategies and obtaining the corresponding dual-axis signal response results, signal analysis processing will be performed on the results of the two excitation strategies. Through this analysis process, the first frequency response corresponding to the first excitation strategy will be obtained (…). and The second frequency response corresponding to the second incentive strategy ( and Each set of frequency responses contains two types of core response information: one is the frequency self-response of the excited measurement axis itself, and the other is the coupled frequency response generated by the unexcited measurement axis due to inter-axis coupling. These two types of responses together constitute complete frequency response data reflecting the dual-axis signal transmission characteristics of the atomic magnetometer.

[0067] Step S202: Determine the corresponding coupling matrix based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy;

[0068] Specifically, the frequency self-response function containing the first measurement axis obtained based on the first excitation strategy. The coupling frequency response function of the second measurement axis The first frequency response, and the frequency self-response function containing the second measurement axis obtained under the second excitation strategy. Coupled frequency response function of the first measurement axis The second frequency response integrates the core data characterizing the response characteristics of each measurement axis and the cross-coupling response characteristics between the two sets of frequency responses. Following the construction rules of a 2×2 matrix, the frequency self-response function of the first measurement axis is... The coupling frequency response function of the second measurement axis Frequency self-response function of the second measurement axis The coupling frequency response function of the second measurement axis The elements are filled into the specified positions in the matrix respectively. At the same time, the signs of the elements in the matrix are corrected by combining the positive and negative relationships of each response signal after the correlation coefficient correction. Finally, a coupling matrix that can completely and accurately characterize the inter-axis coupling characteristics and the response law of each axis of the dual-axis atomic magnetometer system is determined.

[0069] ;

[0070] Among them, off-diagonal elements represent inter-axis coupling.

[0071] Step S203: Determine the decoupling filter matrix corresponding to the coupling matrix, and convert the decoupling filter matrix into the corresponding time-domain filter coefficients;

[0072] Specifically, based on the established dual-axis coupling matrix of the atomic magnetometer, the frequency domain decoupling filter matrix corresponding to the coupling matrix can be obtained through matrix inversion. This decoupling filter matrix can accurately cancel the self-response and coupling response characteristics between the two axes represented by the coupling matrix. Then, through inverse discrete Fourier transform or digital filter design methods, the frequency domain decoupling filter matrix is ​​transformed into time domain filter coefficients adapted to real-time signal processing, providing a directly callable engineering coefficient basis for real-time decoupling of dual-axis signals in the subsequent actual measurement process of the atomic magnetometer.

[0073] It should be noted that the decoupling filter can be implemented using a finite impulse response (FIR) or infinite impulse response (IIR) digital filter. The FIR digital filter possesses strict linear phase characteristics, which can avoid phase distortion of the magnetic field signal during decoupling, ensuring the accuracy of the timing and phase information of the measured signal. Furthermore, its limited unit impulse response ensures structural stability, prevents feedback and divergence, and is suitable for the engineering requirements of real-time decoupling in atomic magnetometers. The IIR digital filter, on the other hand, achieves filtering effects comparable to the FIR filter with a lower order, offering advantages such as low computational load and low hardware resource consumption. This improves the computational efficiency of decoupling processing and is suitable for the hardware deployment scenarios of miniaturized atomic magnetometers. Both digital filter types can flexibly load the time-domain coefficients transformed from the aforementioned decoupling filter matrix, allowing for flexible selection based on the application scenario of the atomic magnetometer (such as the stringent phase requirements of high-precision biomagnetic imaging and the computational efficiency demands of portable detection). Simultaneously, the coefficients of the digital filters can be updated online, adapting to changes in coupling characteristics caused by slow system drift, continuously ensuring inter-axis coupling suppression effects. Moreover, no changes to the atomic magnetometer hardware structure are required; filter optimization can be achieved solely through software updates, significantly improving the engineering practicality and adaptability of the decoupling solution.

[0074] Step S204: When the atomic magnetometer performs actual dual-axis measurement based on a preset high-frequency modulation field, the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis are acquired in real time. The first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis are decoupled based on the time-domain filter coefficients to obtain the first decoupled signal corresponding to the first measurement axis and the second decoupled signal corresponding to the second measurement axis.

[0075] Specifically, when the atomic magnetometer performs actual biaxial magnetic field measurement based on a preset high-frequency modulation field, the biaxial measurement signals are synchronously acquired in real time. The first measured time-domain signal corresponding to the first measurement axis and the second measured time-domain signal corresponding to the second measurement axis are accurately obtained. The first measured signal and the second measured signal are decoupled using the time-domain filter coefficients obtained in advance by the decoupling filter matrix. This accurately cancels the interaxial coupling interference caused by system non-ideals such as atomic spin dynamics coupling, non-orthogonality of optical and magnetic fields, and non-ideal alignment of magnetic coils. Finally, the first decoupling signal corresponding to the first measurement axis and the second decoupling signal corresponding to the second measurement axis, which have eliminated the influence of coupling crosstalk and can truly reflect the actual magnetic field situation, are obtained as the valid results of the biaxial magnetic field measurement.

[0076] Figure 3This is a comparison diagram of the coupling suppression of the second measurement axis to the first measurement axis before and after, according to an embodiment of this application. In this experiment, excitation magnetic field signals with an amplitude of 100 pT and a frequency of 30.5 Hz were applied to the X and Z axes, respectively. The response signals were collected and processed by Fourier transform. The vertical axis represents sensitivity, with units of fT / Hz. 1 / 2 The graph represents the magnetic field response sensitivity at various frequency bands, with the horizontal axis representing frequency in Hz. The core focus is on the sensitivity changes of the coupling signal. Specifically, the blue line (X-axis plus calibration X-axis response) represents the X-axis response signal acquired only after applying an excitation signal with an amplitude of 100 pT and a frequency of 30.5 Hz to the X-axis; the red line (Z-axis plus calibration X-axis response) represents the X-axis response signal acquired only after applying an excitation signal with an amplitude of 100 pT and a frequency of 30.5 Hz to the Z-axis. Using the inter-axis coupling suppression method proposed in this application, the coupling ratio of the Z-axis to the X-axis is significantly reduced from 23.07% before suppression to 2.96% after suppression. This clearly demonstrates the significant suppression effect of this method on inter-axis coupling from the Z-axis to the X-axis, greatly reducing the interference of the Z-axis magnetic field signal on the high-precision measurement of the X-axis magnetic field.

[0077] Figure 4 This is a comparison diagram of the coupling suppression of the first measurement axis to the second measurement axis before and after according to an embodiment of this application. In this experiment, an excitation magnetic field signal with an amplitude of 100 pT and a frequency of 30.5 Hz was applied to the X and Z axes respectively. The vertical axis represents the response sensitivity of each frequency band (unit: fT / Hz). 1 / 2 The graph shows the sensitivity change of the X-axis to the Z-axis coupling signal, with the horizontal axis representing frequency (Hz). The blue line (X-axis plus calibrated Z-axis response) represents the Z-axis response signal acquired only after applying an excitation signal of 100 pT and 30.5 Hz to the X-axis; the red line (Z-axis plus calibrated Z-axis response) represents the Z-axis response signal acquired only after applying an excitation signal of 100 pT and 30.5 Hz to the Z-axis. Using the inter-axis coupling suppression method proposed in this application, the X-axis to Z-axis coupling ratio was reduced from 16.36% before suppression to 3.01% after suppression, demonstrating that this method also has excellent suppression effect on the reverse inter-axis coupling from the X-axis to the Z-axis, effectively eliminating the distortion effect of the X-axis magnetic field signal on the Z-axis magnetic field measurement.

[0078] Figure 3 and Figure 4 The results corroborate each other, showing that the dual-axis coupling suppression method can reduce magnetic field signal coupling interference between the X and Z axes in a bidirectional and efficient manner. Moreover, the remaining coupling ratio after the coupling suppression is controlled at around 3%, which greatly improves the magnetic field measurement accuracy and inter-axis signal independence of the dual-axis SERF atomic magnetometer.

[0079] In the above steps, after applying a preset high-frequency modulation field to the measurement axis of the dual-axis atomic magnetometer, a single-axis excitation strategy is independently executed and the frequency response, including self-response and coupling response, is analyzed. Based on this, a coupling matrix is ​​constructed, inverted to obtain a decoupling filter matrix, and converted into time-domain filter coefficients. Finally, in actual dual-axis measurement, the real-time acquired dual-axis measured signal is decoupled based on these coefficients. This effectively solves the problem of inter-axis signal crosstalk caused by system non-ideals such as atomic spin dynamics coupling, non-orthogonality of optical and magnetic fields, and non-ideal alignment of magnetic coils in the dual-axis SERF atomic magnetometer. It achieves accurate modeling and real-time digital decoupling of dual-axis coupled signals, significantly reducing the proportion of inter-axis coupling without modifying the hardware. This significantly improves the independence, accuracy, and signal resolution of dual-axis magnetic field measurement. Moreover, this method is compatible with linear time-invariant systems and can adapt to coupling characteristics at different operating points and frequency ranges. It can also achieve online updating of filter coefficients through periodic recalibration to adapt to the slow drift of the system, enabling the dual-axis atomic magnetometer to have more reliable measurement performance in high-precision magnetic field measurement scenarios such as biomagnetic imaging, geophysical exploration, and basic physics research.

[0080] In some embodiments, determining the decoupling filter matrix corresponding to the coupling matrix includes:

[0081] Inverting the coupling matrix yields the decoupling filter matrix.

[0082] Specifically, by performing matrix inversion on the 2×2 frequency domain coupling matrix of the atomic magnetometer's biaxial self-response characteristics and interaxial coupling characteristics, and using the mathematical principle of matrix inversion, the inverse matrix H corresponding to this coupling matrix is ​​solved. -1 (f) and uses the inverse matrix as the decoupling filter matrix. This decoupling filter matrix has a complementary and canceling mathematical relationship with the original coupling matrix, and can accurately match the self-response and coupling response of the original coupling matrix at the frequency domain level. The formula for calculating the decoupling filter matrix is:

[0083] ;

[0084] Where G(f) is the decoupling filter matrix; The frequency self-response function of the first measurement axis; The coupling frequency response function of the second measurement axis; The frequency self-response function of the second measurement axis; Let be the coupling frequency response function of the first measurement axis.

[0085] In the above steps, the decoupling filter matrix is ​​obtained by inverting the coupling matrix that characterizes the self-response and inter-axis coupling characteristics of the dual-axis SERF atomic magnetometer. This matrix forms a complementary and canceling mathematical relationship with the original coupling matrix, which can accurately match and cancel the dual-axis self-response law and inter-axis cross-coupling response law characterized by the original coupling matrix at the frequency domain level. This lays the core frequency domain processing foundation for converting it into time-domain filter coefficients and carrying out real-time digital decoupling in actual measurements. It also provides the theoretical basis for the decoupling filter to accurately eliminate inter-axis coupling interference, ensuring the effective suppression of inter-axis crosstalk in the subsequent real-time decoupling stage.

[0086] In some embodiments, after applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, a first excitation strategy and a second excitation strategy for the atomic magnetometer are executed independently, including:

[0087] After applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, a first magnetic field excitation is applied to the first measurement axis while keeping the excitation of the second measurement axis at zero, thus obtaining the execution result of the first excitation strategy; a second magnetic field excitation is applied to the second measurement axis while keeping the excitation of the first measurement axis at zero, thus obtaining the execution result of the second excitation strategy.

[0088] Specifically, after applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer to bring the magnetometer into a stable working state of dual-axis magnetic field measurement, two types of excitation strategies are executed sequentially according to the principle of independent and interference-free operation. First, a preset first magnetic field excitation is applied to the first measurement axis alone. Simultaneously, the excitation input of the second measurement axis is kept at zero, and all signal response results of the dual axes under this excitation condition are collected synchronously as the execution result of the first excitation strategy. and Then, a preset second magnetic field excitation is applied separately to the second measuring axis. Simultaneously, the excitation input of the first measurement axis is set to zero, and the signal response results of the two axes under this excitation condition are collected as the execution result of the second excitation strategy. and The execution processes of the two types of excitation strategies do not affect each other, ensuring that the collected response signals can accurately reflect the system response characteristics when a single measurement axis is excited.

[0089] Through the above steps, the signal acquisition effect of single-axis excitation and dual-axis acquisition can be achieved, effectively separating the self-response signal of the measurement axis itself and the coupling response signal between axes. This provides an independent and accurate experimental data foundation for subsequent analysis to obtain the frequency response containing the self-response and coupling response, and to accurately construct the coupling matrix characterizing the coupling characteristics of the system. It avoids the problem of response signal aliasing caused by simultaneous dual-axis excitation, and allows the system identification stage to clearly identify the self-response law of each measurement axis and the coupling transmission law between axes.

[0090] In some embodiments, a corresponding coupling matrix is ​​determined based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy, including:

[0091] Based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy, the corresponding initial coupling matrix is ​​determined;

[0092] The first correlation coefficient is calculated based on the self-response signal of the first measurement axis in the execution result of the first excitation strategy and the coupling signal of the first measurement axis in the execution result of the second excitation strategy.

[0093] The second correlation coefficient is calculated based on the self-response signal of the second measurement axis in the execution result of the second excitation strategy and the coupling signal of the second measurement axis in the execution result of the first excitation strategy.

[0094] The initial coupling matrix is ​​corrected based on the first and second correlation coefficients to obtain the coupling matrix.

[0095] Specifically, after completing the execution and frequency response analysis of the dual-axis excitation strategy, an initial coupling matrix of the system is first constructed based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy. The first frequency response includes the frequency self-response function of the first measurement axis and the coupled frequency response function of the second measurement axis; the second frequency response includes the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis. These four core frequency response functions are filled into the diagonal and off-diagonal positions of the matrix according to the construction rules of a 2×2 matrix. The diagonal elements represent the response characteristics of each measurement axis itself, and the off-diagonal elements represent the coupling response characteristics between axes, thus forming an initial coupling matrix that can initially reflect the coupling law of the dual-axis SERF atomic magnetometer system.

[0096] After obtaining the initial coupling matrix, it is necessary to accurately correct the matrix by calculating the correlation coefficient. First, the first correlation coefficient is calculated, which is obtained from the self-response signal of the first measurement axis in the execution result of the first excitation strategy. The first measurement axis coupling signal in the execution result of the second excitation strategy Using this as the core data, a first correlation coefficient reflecting the correlation characteristics and positive / negative relationship between the two sets of time-domain signals was obtained through correlation analysis. Subsequently, a second correlation coefficient was calculated using the same correlation analysis method, and the self-response signal of the second measurement axis from the execution result of the second excitation strategy was selected. The second measurement axis coupling signal in the execution result of the first excitation strategy As the object of analysis, the second correlation coefficient, which characterizes the correlation between the two sets of signals, is obtained by performing correlation calculations on the time-domain characteristics of the two sets of signals.

[0097] Finally, the initial coupling matrix is ​​comprehensively corrected based on the first and second correlation coefficients obtained from the solution. According to the sign and magnitude of the correlation coefficients, the signs of the elements in the initial coupling matrix are adjusted to correct the deviations in the sign and amplitude of the frequency response function caused by non-ideal factors of the system. This allows the matrix elements to accurately match the actual dual-axis self-response characteristics and inter-axis coupling characteristics, and finally obtains a coupling matrix that can completely and accurately characterize the true coupling law of the dual-axis SERF atomic magnetometer system.

[0098] Specifically, one method for correcting the sign of elements in the initial coupling matrix can be: if the first correlation coefficient is greater than 0, then... and Either one is negative; otherwise, the sign remains unchanged. If the second correlation coefficient is greater than 0, then... and Either one is negative; otherwise, the sign remains unchanged.

[0099] In the above steps, by combining the characteristics of the magnetic field having directionality and the coupling coefficient (coupling response function) having positive and negative distinctions, an initial coupling matrix that initially reflects the coupling characteristics of the system is first constructed based on the frequency response obtained from the independent excitation of the two axes. Then, by calculating the positive and negative relationships between the response of the non-sensitive axis signal to the sensitive axis and the response of the sensitive axis itself using two sets of correlation coefficients, the initial coupling matrix is ​​specifically corrected. Finally, a coupling matrix that can accurately match the actual system characteristics of the dual-axis SERF atomic magnetometer and contains the correct positive and negative attributes and amplitudes is obtained. This effectively solves the problem of low decoupling success rate caused by the positive and negative characteristics of the coupling coefficient, allowing the coupling matrix to truly and completely represent the coupling law between the two axes and the self-response law of each axis. This provides an accurate and reliable matrix foundation for the design of the subsequent decoupling filter matrix, and fundamentally ensures the effectiveness and accuracy of subsequent digital decoupling.

[0100] In some embodiments, the execution results of the incentive strategy are analyzed to obtain a first frequency response corresponding to the first incentive strategy and a second frequency response corresponding to the second incentive strategy, including:

[0101] The execution results of the first excitation strategy are analyzed to obtain the frequency self-response function of the first measurement axis and the coupled frequency response function of the second measurement axis. Based on the frequency self-response function of the first measurement axis and the coupled frequency response function of the second measurement axis, the first frequency response corresponding to the first excitation strategy is obtained.

[0102] The execution results of the second excitation strategy are analyzed to obtain the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis. Based on the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis, the second frequency response corresponding to the second excitation strategy is obtained.

[0103] Specifically, after independently executing the first excitation strategy and obtaining the corresponding execution results, a targeted frequency response analysis is performed on the results to extract the self-response signal of the first measurement axis from the execution results of the first excitation strategy. Coupled signal with the second measurement axis By processing the two types of signals using signal analysis methods, the frequency self-response function of the first measurement axis is obtained. and the coupling frequency response function of the second measurement axis. By integrating these two functions, the first measurement axis frequency self-response function is taken as the core self-response feature, and the second measurement axis coupling frequency response function is taken as the inter-axis coupling feature. Together, they constitute the first frequency response corresponding to the first excitation strategy. This frequency response fully reflects the full-dimensional frequency characteristics of the system's self-response and inter-axis coupling when only the first measurement axis is subjected to magnetic field excitation.

[0104] For the execution result of the second excitation strategy, the same logic and method as the analysis of the first excitation strategy result are used for frequency response analysis. First, the self-response signal of the second measurement axis is separated from the execution result of the second excitation strategy. Coupled response signal with the first measurement axis Then, frequency domain analysis and solutions are performed on the two types of signals to obtain the frequency self-response function of the second measurement axis. and the coupling frequency response function of the first measurement axis. Based on these two functions, the second measurement axis frequency self-response function and the first measurement axis coupling frequency response function are combined and constructed as the core frequency features of the self-response and coupling response, respectively, forming the second frequency response corresponding to the second excitation strategy. This frequency response accurately presents the self-response and inter-axis coupling frequency characteristics of the system when only the second measurement axis is excited by a magnetic field.

[0105] Through the above steps, the frequency response of the system under dual-axis independent excitation was accurately decomposed and integrated. The self-response frequency characteristics of each measurement axis and the coupling frequency characteristics between axes were extracted respectively. The resulting first and second frequency responses clearly distinguished the different laws of self-response and coupling response, while completely preserving all the frequency characteristics of the system under single-axis excitation. This provides a complete and accurate frequency domain data foundation for the subsequent construction of a coupling matrix that can accurately characterize the coupling law of the system based on the frequency response. At the same time, it also enables the subsequent system identification process to accurately identify the coupling transmission characteristics between the two axes and the response characteristics of each axis itself. From the frequency domain level, this lays a reliable theoretical and data support for the subsequent decoupling design.

[0106] In some embodiments, the execution result of the first excitation strategy includes a first measurement axis self-response signal corresponding to the first measurement axis and a second measurement axis coupling signal corresponding to the second measurement axis;

[0107] The execution results of the first excitation strategy are analyzed to obtain the frequency self-response function of the first measurement axis and the coupled frequency response function of the second measurement axis, including:

[0108] Fourier transforms are performed on the first magnetic field excitation, the first measurement axis self-response signal, and the second measurement axis coupling signal to obtain the first frequency domain magnetic field excitation corresponding to the first magnetic field excitation, the first measurement axis frequency domain self-response signal corresponding to the first measurement axis self-response signal, and the second measurement axis frequency domain coupling signal corresponding to the second measurement axis coupling signal.

[0109] Based on the first frequency domain magnetic field excitation and the first measurement axis frequency domain self-response signal, the frequency self-response function of the first measurement axis is obtained;

[0110] Based on the first frequency domain magnetic field excitation and the second measurement axis frequency domain coupling signal, the coupling frequency response function of the second measurement axis is obtained.

[0111] Specifically, after executing the first excitation strategy, the obtained execution results include two types of core signals: one is the self-response signal of the first measurement axis generated after the first measurement axis is excited by the first magnetic field. One type of signal directly reflects the correspondence between the magnetic field excitation of the first measuring axis and the signal response; the other type is the second measuring axis coupling signal generated by the first magnetic field excitation due to the inter-axis coupling effect. This signal reflects the cross-coupling transmission characteristics between the two axes. The two types of signals together constitute the basic data for analyzing the self-response of the first measurement axis and the frequency characteristics of the inter-axis coupling.

[0112] To extract the frequency domain response pattern from the execution result, the first magnetic field excitation, the first measurement axis self-response signal, and the second measurement axis coupling signal need to be subjected to Fourier transform processing, respectively. These three sets of time-domain signals are then converted to the frequency domain, thereby obtaining the first frequency-domain magnetic field excitation corresponding to the first magnetic field excitation. The frequency domain self-response signal of the first measurement axis corresponding to the self-response signal of the first measurement axis. And the second measurement axis frequency domain coupling signal corresponding to the second measurement axis coupling signal. This completes the dimensional transformation of the signal from the time domain to the frequency domain, providing frequency domain data support for the subsequent solution of the frequency response function.

[0113] After obtaining three sets of frequency domain signals, calculations are performed based on the correspondence between excitation and response in the frequency domain. The ratio of the frequency domain self-response signal of the first measurement axis to the first frequency domain magnetic field excitation is calculated to obtain the frequency self-response function of the first measurement axis, which can accurately characterize the self-excitation and response characteristics of the first measurement axis at different frequencies. The calculation formula is as follows:

[0114] ;

[0115] in, This is the frequency domain self-response signal of the first measurement axis; This is the first frequency domain magnetic field excitation.

[0116] Simultaneously, the second measurement axis frequency domain coupling signal is... Excitation with the first frequency domain magnetic field By performing ratio calculations, we obtain the shaft coupling frequency response function of the second measurement axis, which reflects the influence of the excitation of the first measurement axis on the coupling of the second measurement axis at different frequencies. The calculation formula is as follows:

[0117] ;

[0118] in, The second measurement axis is a frequency domain coupled signal; This is the first frequency domain magnetic field excitation.

[0119] In the above steps, the conversion from time-domain signal to frequency-domain signal is achieved through Fourier transform, mapping the self-response and coupling response characteristics of the two axes from the time dimension to the frequency dimension. The self-response law of the first measurement axis and the coupling transfer law between axes at each frequency are accurately solved. The obtained frequency self-response function and coupling frequency response function can completely and meticulously reflect the response characteristics of the system in the full frequency range. This provides quantified frequency-domain feature parameters for subsequent integration to form the first frequency response and construct an accurate coupling matrix. At the same time, it also enables the system identification process to achieve fine identification of the dual-axis coupling characteristics based on the frequency dimension, laying a precise frequency-domain theoretical foundation for the design of subsequent decoupling filters.

[0120] In some embodiments, the execution result of the second excitation strategy includes the second measurement axis self-response signal corresponding to the second measurement axis and the first measurement axis coupling signal corresponding to the first measurement axis;

[0121] The execution results of the second excitation strategy are analyzed to obtain the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis, including:

[0122] Fourier transforms are performed on the second magnetic field excitation, the second measurement axis self-response signal, and the first measurement axis coupling signal to obtain the second frequency domain magnetic field excitation corresponding to the second magnetic field excitation, the second measurement axis frequency domain self-response signal corresponding to the second measurement axis self-response signal, and the first measurement axis frequency domain coupling signal corresponding to the first measurement axis coupling signal.

[0123] Based on the second frequency domain magnetic field excitation and the second measurement axis frequency domain self-response signal, the frequency self-response function of the second measurement axis is obtained;

[0124] Based on the second frequency domain magnetic field excitation and the first measurement axis frequency domain coupling signal, the coupling frequency response function of the first measurement axis is obtained.

[0125] Specifically, after executing the second excitation strategy, the execution result includes two types of key signals: one is the self-response signal of the second measurement axis directly generated by the excitation of the second magnetic field on the second measurement axis. This signal directly reflects the correspondence between the excitation of the second measuring axis's own magnetic field and the signal response, and is the core data characterizing the response characteristics of the second measuring axis itself; secondly, due to the coupling effect between the two axes, the excitation of the second magnetic field indirectly triggers the first measuring axis coupling signal generated by the first measuring axis. This signal reflects the cross-coupling transmission characteristics of the excitation of the second measurement axis to the first measurement axis, and is an important basis for identifying the coupling law between axes. The two types of signals together constitute the basic time-domain data for analyzing the self-response of the second measurement axis and the frequency characteristics of the coupling between axes.

[0126] To extract the frequency-dimensional response pattern from the execution results in the time domain, Fourier transform processing needs to be performed on the second magnetic field excitation, the self-response signal of the second measurement axis, and the coupling signal of the first measurement axis. This process maps these three sets of time-domain signals from the time dimension to the frequency dimension, thereby obtaining the second frequency-domain magnetic field excitation corresponding to the second magnetic field excitation. The second measurement axis self-response signal corresponding to the second measurement axis frequency domain self-response signal And the first measurement axis frequency domain coupling signal corresponding to the first measurement axis coupling signal This transformation allows the excitation and response characteristics of the system to be quantified in the frequency domain, providing accurate frequency domain data support for the subsequent solution of the frequency response function.

[0127] After obtaining three sets of corresponding frequency domain signals, calculations are performed based on the correlation between excitation and response in the frequency domain. The frequency domain self-response signal of the second measurement axis is compared with the second frequency domain magnetic field excitation to obtain the frequency self-response function of the second measurement axis, which can accurately characterize the self-excitation and response of the second measurement axis at different frequencies. The specific formula is as follows:

[0128] ;

[0129] in, This is the frequency domain self-response signal of the second measurement axis; This is the second frequency domain magnetic field excitation.

[0130] Simultaneously, the ratio of the frequency-domain coupled signal of the first measurement axis to the frequency-domain magnetic field excitation of the second measurement axis is calculated to obtain the coupling frequency response function of the first measurement axis, which reflects the coupling characteristics of the second measurement axis excitation on the first measurement axis at different frequencies. The specific formula is as follows:

[0131] ;

[0132] in, The first measurement axis is the frequency domain coupled signal; This is the second frequency domain magnetic field excitation.

[0133] In the above steps, Fourier transform is used to achieve accurate conversion of time-domain signals to frequency-domain signals. The self-response and inter-axis coupling characteristics of the second measurement axis under single-axis excitation are decomposed from the time dimension to the frequency dimension for quantitative analysis. The solved frequency self-response function and coupled frequency response function can completely and meticulously reflect the self-response law of the second measurement axis at different frequencies and the coupling transmission law to the first measurement axis. This provides quantified frequency-domain characteristic parameters for subsequent integration to form the second frequency response and construct an accurate system coupling matrix. At the same time, it enables the system identification process to achieve fine identification of dual-axis coupling characteristics based on the frequency dimension, laying a reliable and accurate theoretical and data foundation for the subsequent frequency-domain design of decoupling filters.

[0134] In some embodiments, the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis are decoupled based on time-domain filter coefficients to obtain a first decoupled signal corresponding to the first measurement axis and a second decoupled signal corresponding to the second measurement axis, including:

[0135] Based on the time-domain filter coefficients, a convolution operation is performed on the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis to obtain the first decoupling signal corresponding to the first measurement axis and the second decoupling signal corresponding to the second measurement axis.

[0136] Specifically, in the process of conducting actual biaxial magnetic field measurements using an atomic magnetometer based on a preset high-frequency modulation field, after completing the conversion from the decoupling filter matrix to the time-domain filter coefficients, the real-time decoupling processing stage of the measured signal begins. This stage requires synchronous, delay-free acquisition of the biaxial measured magnetic field signals to accurately obtain the first measured time-domain signal corresponding to the first measurement axis. The second measured time-domain signal corresponding to the second measurement axis These two sets of signals are the original measurement signals containing inter-axis coupling interference, and they are also the core objects of subsequent decoupling processing.

[0137] After obtaining the dual-axis measured signals, digital convolution operations are performed on the first and second measured signals using the pre-converted time-domain filter coefficients as the core processing basis. This convolution operation is not an independent operation on a single signal, but rather combines the correction parameters corresponding to the self-response and coupling response in the time-domain filter coefficients to perform cross-convolution processing on the dual-axis measured signals. This allows the decoupling characteristics of the filter coefficients to fully apply to the measured signals containing coupling interference, canceling the coupling components of crosstalk between the two axes through computation. During the convolution operation, the time-domain filter coefficients retain the effective magnetic field signals in the first and second measured signals based on the coupling rules identified by the system in the early stages, while accurately eliminating inter-axis coupling interference signals caused by non-ideal system factors such as atomic spin dynamics coupling, non-orthogonality of the optical and magnetic fields, and mechanical alignment deviations of the magnetic coils. Finally, the first decoupling signal corresponding to the first measurement axis and the second decoupling signal corresponding to the second measurement axis are obtained, completing the full-process decoupling processing of the dual-axis measured signals. The specific formula is as follows:

[0138] ;

[0139] ;

[0140] in, This is the first decoupling signal; This is the second decoupling signal; , , and These are the time-domain filter coefficients; This is the first measured time-domain signal; This is the second measured time-domain signal.

[0141] The above steps, through convolution operations, transform the characteristics of the frequency-domain decoupling filter matrix into the actual correction effect of the time-domain measured signal, achieving accurate and real-time elimination of coupling interference in the dual-axis measured signal. This allows the decoupled signal to truly reflect the actual magnetic field distribution, effectively solving the problem of measurement result distortion caused by inter-axis signal crosstalk in dual-axis SERF atomic magnetometer measurements. Furthermore, the digital implementation of convolution operations requires no hardware modification and can be directly completed in the signal processing unit of the measurement and control system, ensuring the real-time performance and engineering feasibility of the decoupling process. This significantly improves the accuracy and independence of dual-axis magnetic field measurements, providing reliable signal data support for high-precision magnetic field measurement scenarios such as biomagnetic imaging and geophysical exploration.

[0142] In some embodiments, both the first magnetic field excitation and the second magnetic field excitation are either white noise or a linear frequency modulated signal.

[0143] In the process of implementing the first and second excitation strategies on the atomic magnetometer, the first and second magnetic field excitations are both selected from white noise signals or linear frequency modulated signals. Both types of excitation signals have the characteristic of wide frequency domain coverage, which can excite the dual-axis system of the atomic magnetometer in the full frequency range. This adapts to the self-response and coupling response characteristics of the dual-axis SERF atomic magnetometer at different frequencies, providing full-band excitation data support for frequency response analysis in the system identification stage.

[0144] The above embodiments, by selecting white noise or linear frequency modulated signals as magnetic field excitation, can achieve wideband excitation of the dual-axis atomic magnetometer system, fully exciting the system's self-response and inter-axis coupling response characteristics at each frequency point. This allows subsequent frequency response analysis to accurately capture the system coupling law across the entire frequency range, avoiding the drawback of narrowband excitation signals only reflecting local frequency characteristics. The constructed coupling matrix can comprehensively and accurately characterize the system's coupling characteristics across the entire operating frequency range, laying a precise data foundation across the entire frequency band for the subsequent design of decoupling filters. This ensures that the decoupling filters can achieve good inter-axis coupling suppression effects at different frequencies.

[0145] In some embodiments, the above-described inter-axis coupling suppression method further includes periodically re-executing the system response identification and filter update steps to adapt to system drift.

[0146] Specifically, according to a preset time period or when changes in the working environment or parameters of the atomic magnetometer are detected, a preset high-frequency modulation field is reapplied to the dual axes of the atomic magnetometer. The first and second excitation strategies are executed independently in sequence, and the new frequency response is analyzed. Based on the new frequency response, the corrected coupling matrix is ​​reconstructed, and then the new decoupling filter matrix is ​​obtained by inversion and transformed into time-domain filter coefficients that adapt to the current system state. This completes the online update of the decoupling filter and realizes dynamic adaptation to system drift.

[0147] In the above steps, by periodically re-executing the system response identification and filter update steps, the coupling characteristics of the atomic magnetometer can be effectively adapted to changes caused by non-ideal factors such as device aging, slow changes in the ambient magnetic field, and drift of optical and magnetic field parameters due to long-term operation. This ensures that the coefficients of the decoupling filter are always precisely matched with the actual coupling law of the current system, avoiding the problem of decoupling effect decay due to system drift. This continuously ensures the effectiveness of inter-axis coupling suppression, enabling the dual-axis SERF atomic magnetometer to maintain a low inter-axis coupling ratio and high magnetic field measurement accuracy during long-term continuous measurement work. This significantly improves the stability and reliability of the coupling suppression method in practical engineering applications, making it suitable for application scenarios that require continuous high-precision magnetic field measurement, such as biomagnetic imaging and long-term geophysical exploration.

[0148] This embodiment also provides an inter-axis coupling suppression device for implementing the above embodiments and preferred embodiments, which will not be repeated hereafter. As used below, the terms "module," "unit," "subunit," etc., can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0149] Figure 5 This is a structural block diagram of an inter-axis coupling suppression device according to an embodiment of this application, such as... Figure 5 As shown, the device includes:

[0150] The response identification module 51 is used to independently execute a first excitation strategy and a second excitation strategy for the atomic magnetometer after applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, and analyze the execution results of the excitation strategies to obtain a first frequency response corresponding to the first excitation strategy and a second frequency response corresponding to the second excitation strategy. The frequency response includes the frequency response of the measurement axis itself and the coupling response between the measurement axes. The first excitation strategy is used to indicate that only the first magnetic field excitation is applied to the first measurement axis; the second excitation strategy is used to indicate that only the second magnetic field excitation is applied to the second measurement axis; and the corresponding coupling matrix is ​​determined based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy.

[0151] The time-domain filter coefficient generation module 52 is used to determine the decoupling filter matrix corresponding to the coupling matrix and convert the decoupling filter matrix into the corresponding time-domain filter coefficients.

[0152] The real-time decoupling module 53 is used to acquire the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis in real time when the atomic magnetometer performs actual dual-axis measurement based on a preset high-frequency modulation field, and to decouple the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis based on the time-domain filter coefficients to obtain the first decoupling signal corresponding to the first measurement axis and the second decoupling signal corresponding to the second measurement axis.

[0153] It should be noted that the above modules can be functional modules or program modules, and can be implemented by software or hardware. For modules implemented by hardware, the above modules can reside in the same processor; or the above modules can be located in different processors in any combination. Specific examples in this embodiment can be found in the examples described in the above embodiments and optional implementations, and will not be repeated in this embodiment.

[0154] As an example, this embodiment also provides an experimental setup for a biaxial SERF atomic magnetometer. Please refer to [link to relevant documentation]. Figure 6 Specifically, it includes: a miniaturized dual-axis SERF atomic magnetometer 61, a large triaxial magnetic coil 62, a magnetic shielding module 63, a laser module 64, an electronic control module 65, and a host computer 66.

[0155] The miniaturized biaxial SERF atomic magnetometer 61 is placed at the center of a large triaxial magnetic coil for measuring biaxial magnetic fields. (See also...) Figure 7 Specifically, it includes a polarization-maintaining fiber 6101, a collimator 6102, a combined prism 6103, a right-angle mirror 6104, a heating film 6105, an oven 6106, an alkali metal gas chamber 6107, an integrated triaxial magnetic coil 6108, a circularly polarized pump light 6109, a photodetector 6110, a platinum resistance thermometer 6111, a connecting line 6112, a supporting structure 6113, and a line connecting plate 6114. The polarization-maintaining fiber 6101 connects to the laser module 64 to guide the light source to the probe. The collimator 6102 collimates the light source, which then passes through the combined prism 6103, the right-angle mirror 6104, and the alkali metal gas chamber 6107 before being detected by the photodetector 6110. The oven 6106, the heating film 6105, and the platinum resistance thermometer 6111 are used to heat the alkali metal gas chamber 6107 and stabilize it to the operating temperature. The integrated triaxial magnetic coil 6108 is used to generate DC and AC magnetic fields. The wire connection plate 6114 is used to gather the signal lines of the probe together; the connecting wire 6112 is used for signal transmission within the probe and for signal transmission between the probe and the electronic control module 65; the support structure 6113 is used to fix the aforementioned alkali metal gas chamber 6107, optical components and electronic components.

[0156] A large triaxial magnetic coil 62 is placed at the center of the magnetic shielding module 63 to calibrate the coil constant of the integrated triaxial magnetic coil in the probe.

[0157] The magnetic shielding module 63 is a magnetic shielding barrel made of multi-layer permalloy, used to shield the ambient magnetic field.

[0158] Laser module 64 is a semiconductor laser that provides a light source for the probe.

[0159] The electronic control module 65 includes a measurement and control system and a host computer operating system. The measurement and control system includes a temperature control unit, a signal generator unit, a laser control unit, a signal processing unit, and a data acquisition unit. The temperature control unit is used to detect and monitor the temperature of the gas chamber; the signal generator unit is used to generate the DC and AC signals required by the probe; the laser control unit is used to control the semiconductor laser; the signal processing unit is used to process the dual-axis magnetic field and implement the dual-axis coupling suppression method proposed in this application; the data acquisition unit is used to acquire the dual-axis magnetic field signal; and the host computer operating system is used to issue commands to ensure the normal operation of the miniaturized dual-axis SERF atomic magnetometer.

[0160] Figure 8 This is a schematic diagram of the overall process of the inter-axis coupling suppression method according to an embodiment of this application. Step 1: Start the dual-axis SERF atomic magnetometer experimental device and debug the dual-axis SERF atomic magnetometer to enable it to synchronously measure the dual-axis magnetic field; Step 2: The dual-axis SERF atomic magnetometer responds and identifies, applying known excitation magnetic field signals to the x-axis and z-axis respectively, acquiring the corresponding dual-axis output signals, and obtaining the 2×2 coupling matrix H(f) of the system through time-domain signal frequency response and correlation coefficient analysis; Step 3: Decoupling filter design, inverting the coupling matrix to obtain the decoupling filter matrix G(f) = H. -1 (f); Step 4: Decouple in real time and output the decoupling result. In the actual measurement process, the real-time acquired dual-axis signal is input into the decoupling filter, and the decoupled dual-axis magnetic field estimate is obtained through convolution operation.

[0161] Furthermore, in conjunction with the inter-axis coupling suppression methods in the above embodiments, this application embodiment can provide a storage medium for implementation. This storage medium stores a computer program; when executed by a processor, the computer program implements any of the inter-axis coupling suppression methods in the above embodiments.

[0162] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0163] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0164] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0165] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for suppressing inter-axis coupling, characterized in that, include: After applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, a first excitation strategy and a second excitation strategy for the atomic magnetometer are executed independently, and the execution results of the excitation strategies are analyzed to obtain a first frequency response corresponding to the first excitation strategy and a second frequency response corresponding to the second excitation strategy. The frequency response includes the frequency response of the measurement axis itself and the coupling response between the measurement axes. The first excitation strategy is used to indicate that only the first magnetic field excitation is applied to the first measurement axis; the second excitation strategy is used to indicate that only the second magnetic field excitation is applied to the second measurement axis. Based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy, the corresponding coupling matrix is ​​determined; Determine the decoupling filter matrix corresponding to the coupling matrix, and transform the decoupling filter matrix into the corresponding time-domain filter coefficients; When the atomic magnetometer performs actual biaxial measurement based on the preset high-frequency modulation field, it acquires the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis in real time, and decouples the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis based on the time-domain filter coefficients to obtain the first decoupled signal corresponding to the first measurement axis and the second decoupled signal corresponding to the second measurement axis.

2. The inter-axis coupling suppression method according to claim 1, characterized in that, Determining the decoupling filter matrix corresponding to the coupling matrix includes: The decoupling filter matrix is ​​obtained by inverting the coupling matrix.

3. The inter-axis coupling suppression method according to claim 1, characterized in that, After applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, the first and second excitation strategies for the atomic magnetometer are executed independently, including: After applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, a first magnetic field excitation is applied to the first measurement axis while keeping the excitation of the second measurement axis at zero, thus obtaining the execution result of the first excitation strategy; a second magnetic field excitation is applied to the second measurement axis while keeping the excitation of the first measurement axis at zero, thus obtaining the execution result of the second excitation strategy.

4. The inter-axis coupling suppression method according to claim 3, characterized in that, The step of determining the corresponding coupling matrix based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy includes: Based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy, the corresponding initial coupling matrix is ​​determined; Based on the self-response signal of the first measurement axis in the execution result of the first excitation strategy and the coupling signal of the first measurement axis in the execution result of the second excitation strategy, the first correlation coefficient is calculated; Based on the second measurement axis self-response signal in the execution result of the second excitation strategy and the second measurement axis coupling signal in the execution result of the first excitation strategy, a second correlation coefficient is calculated; Based on the first correlation coefficient and the second correlation coefficient, the initial coupling matrix is ​​corrected to obtain the coupling matrix.

5. The inter-axis coupling suppression method according to claim 1, characterized in that, The step of analyzing the execution results of the incentive strategy to obtain the first frequency response corresponding to the first incentive strategy and the second frequency response corresponding to the second incentive strategy includes: The execution result of the first excitation strategy is analyzed to obtain the frequency autoresponse function of the first measurement axis and the coupled frequency response function of the second measurement axis. Based on the frequency autoresponse function of the first measurement axis and the coupled frequency response function of the second measurement axis, the first frequency response corresponding to the first excitation strategy is obtained. The execution results of the second excitation strategy are analyzed to obtain the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis. Based on the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis, the second frequency response corresponding to the second excitation strategy is obtained.

6. The inter-axis coupling suppression method according to claim 5, characterized in that, The execution result of the first excitation strategy includes the first measurement axis self-response signal corresponding to the first measurement axis and the second measurement axis coupling signal corresponding to the second measurement axis; The analysis of the execution result of the first excitation strategy to obtain the frequency self-response function of the first measurement axis and the coupled frequency response function of the second measurement axis includes: Fourier transforms are performed on the first magnetic field excitation, the first measurement axis self-response signal, and the second measurement axis coupling signal to obtain the first frequency domain magnetic field excitation corresponding to the first magnetic field excitation, the first measurement axis frequency domain self-response signal corresponding to the first measurement axis self-response signal, and the second measurement axis frequency domain coupling signal corresponding to the second measurement axis coupling signal. Based on the first frequency domain magnetic field excitation and the first measurement axis frequency domain self-response signal, the frequency self-response function of the first measurement axis is obtained; Based on the first frequency domain magnetic field excitation and the second measurement axis frequency domain coupling signal, the coupling frequency response function of the second measurement axis is obtained.

7. The inter-axis coupling suppression method according to claim 5, characterized in that, The execution result of the second excitation strategy includes the second measurement axis self-response signal corresponding to the second measurement axis and the first measurement axis coupling signal corresponding to the first measurement axis; The analysis of the execution result of the second excitation strategy to obtain the frequency self-response function of the second measurement axis and the coupled frequency response function of the first measurement axis includes: Fourier transforms are performed on the second magnetic field excitation, the second measurement axis self-response signal, and the first measurement axis coupling signal to obtain the second frequency domain magnetic field excitation corresponding to the second magnetic field excitation, the second measurement axis frequency domain self-response signal corresponding to the second measurement axis self-response signal, and the first measurement axis frequency domain coupling signal corresponding to the first measurement axis coupling signal. Based on the second frequency domain magnetic field excitation and the second measurement axis frequency domain self-response signal, the frequency self-response function of the second measurement axis is obtained; Based on the second frequency domain magnetic field excitation and the first measurement axis frequency domain coupling signal, the coupling frequency response function of the first measurement axis is obtained.

8. The inter-axis coupling suppression method according to claim 1, characterized in that, The process of decoupling the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis based on the time-domain filter coefficients to obtain the first decoupled signal corresponding to the first measurement axis and the second decoupled signal corresponding to the second measurement axis includes: Based on the time-domain filter coefficients, a convolution operation is performed on the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis to obtain a first decoupled signal corresponding to the first measurement axis and a second decoupled signal corresponding to the second measurement axis.

9. The inter-axis coupling suppression method according to claim 1, characterized in that, Both the first magnetic field excitation and the second magnetic field excitation are either white noise or linear frequency modulated signals.

10. An inter-shaft coupling suppression device, characterized in that, The device includes: The response identification module is used to independently execute a first excitation strategy and a second excitation strategy for the atomic magnetometer after applying a preset high-frequency modulation field to the first and second measurement axes of the atomic magnetometer, and analyze the execution results of the excitation strategies to obtain a first frequency response corresponding to the first excitation strategy and a second frequency response corresponding to the second excitation strategy. The frequency response includes the frequency response of the measurement axis itself and the coupling response between the measurement axes. The first excitation strategy is used to indicate that only the first magnetic field excitation is applied to the first measurement axis; the second excitation strategy is used to indicate that only the second magnetic field excitation is applied to the second measurement axis. Based on the first frequency response corresponding to the first excitation strategy and the second frequency response corresponding to the second excitation strategy, the corresponding coupling matrix is ​​determined. A time-domain filter coefficient generation module is used to determine the decoupling filter matrix corresponding to the coupling matrix and convert the decoupling filter matrix into the corresponding time-domain filter coefficients. The real-time decoupling module is used to acquire, in real time, the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis when the atomic magnetometer performs actual dual-axis measurement based on the preset high-frequency modulation field, and to perform decoupling processing on the first measured signal corresponding to the first measurement axis and the second measured signal corresponding to the second measurement axis based on the time-domain filter coefficients to obtain the first decoupling signal corresponding to the first measurement axis and the second decoupling signal corresponding to the second measurement axis.

Images