CN118671668B

CN118671668B - Weak magnetic field detection system and method

Info

Publication number: CN118671668B
Application number: CN202410942692.5A
Authority: CN
Inventors: 肖君如; 方海军; 李定坤; 徐杰
Original assignee: Leading Yang Technology Shenzhen Co ltd
Current assignee: Leading Yang Technology Shenzhen Co ltd
Priority date: 2024-07-15
Filing date: 2024-07-15
Publication date: 2025-02-14
Anticipated expiration: 2044-07-15
Also published as: CN118671668A

Abstract

The invention provides a weak magnetic field detection system and method, wherein the system comprises a Hall sensor, a magneto-resistance sensor, a miniaturized superconducting quantum interferometer and a signal processing circuit, wherein the Hall sensor is used for detecting a weak magnetic field at a position to be detected to generate a Hall signal and sending the Hall signal, the magneto-resistance sensor is used for detecting the weak magnetic field at the position to be detected to generate a magneto-resistance signal and sending the magneto-resistance signal, the miniaturized superconducting quantum interferometer is used for detecting the weak magnetic field at the position to be detected to generate a superconducting quantum interference signal and sending the superconducting quantum interference signal, and the signal processing circuit at least comprises a fusion module, which is electrically connected with the Hall sensor, the magneto-resistance sensor and the miniaturized superconducting quantum interferometer respectively and used for receiving the Hall signal, the magneto-resistance signal and the superconducting quantum interference signal, fusing the received Hall signal, the magneto-resistance signal and the superconducting quantum interference signal to obtain a multi-source fused magnetic field signal and sending the multi-source fused magnetic field signal, and generating a magnetic field intensity value representing the intensity of the weak magnetic field at the position to be detected according to the received multi-source fused magnetic field signal.

Description

Weak magnetic field detection system and method

Technical Field

The invention relates to the technical field of detection, in particular to a weak magnetic field detection system and a weak magnetic field detection method.

Background

In the wave tide of rapid development of modern technology, the application field of the weak magnetic field detection technology is widened increasingly, and the influence of the weak magnetic field detection technology gradually permeates into a precision workshop manufactured by high-end industry from a deep palace of basic scientific research to the fine field of medical health diagnosis. The accurate detection of weak magnetic fields is not only a technical challenge, but also a key force for promoting technological progress. The method has irreplaceable important values in the aspects of understanding the microcosmic world of magnetic field distribution, deep analysis of material properties, exploration and research of biological magnetic fields and the like.

However, the characteristics of the weak magnetic field make its detection particularly difficult. The strength of the weak magnetic field is typically between the nano-to gauss, and such weak magnetic field signals tend to be submerged in ambient noise and other interfering factors. Therefore, the conventional magnetic field detection method often appears to be frustrated when faced with a weak magnetic field. For example, although the fluxgate technology can measure a weak magnetic field to a certain extent, the problem of insufficient sensitivity and low measurement accuracy of the fluxgate technology is greatly limited in practical application. In addition, factors such as environmental interference and temperature change can have a great influence on the measurement result.

With the continuous development of technology, the requirements on the weak magnetic field detection technology are also higher and higher. First, sensitivity is one of the core indexes of the weak magnetic field detection technology. Only with a sufficiently high sensitivity can a weak magnetic field signal be captured from complex ambient noise. Second, measurement accuracy is also critical. In the fields of scientific research, industrial manufacturing and the like, the accurate grasp of the magnetic field distribution often determines the depth and the breadth of the research. Finally, the response speed is also a non-negligible factor. In some application scenarios, such as medical health diagnosis, magnetic field information needs to be quickly and accurately acquired in order to make timely decisions and decisions.

Disclosure of Invention

In order to solve the above-mentioned problems, the present application provides a weak magnetic field detection system and method, so as to at least solve or alleviate the above-mentioned problems in the prior art.

In order to achieve the above object, according to one aspect of the present application, there is provided a weak magnetic field detection system comprising:

The Hall sensor is used for detecting a weak magnetic field at a position to be detected to generate a Hall signal and transmitting the Hall signal;

the magneto-resistance sensor is used for detecting the weak magnetic field at the position to be detected to generate a magneto-resistance signal and sending the magneto-resistance signal;

the miniaturized superconducting quantum interferometer is used for detecting the weak magnetic field at the position to be detected to generate a superconducting quantum interference signal and transmitting the superconducting quantum interference signal;

A signal processing circuit comprising at least:

the fusion module is respectively and electrically connected with the Hall sensor, the magnetic resistance sensor and the miniaturized superconducting quantum interferometer and is used for receiving the Hall signal, the magnetic resistance signal and the superconducting quantum interference signal, fusing the received Hall signal, the magnetic resistance signal and the superconducting quantum interference signal to obtain a multi-source fusion magnetic field signal and transmitting the multi-source fusion magnetic field signal;

The signal analysis module is used for receiving the multi-source fusion magnetic field signals and generating a magnetic field intensity value representing the weak magnetic field intensity at the position to be detected according to the received multi-source fusion magnetic field signals.

Optionally, the weak magnetic field detection system further comprises a temperature sensor, which is used for detecting the temperature at the position to be detected, so as to compensate the Hall signal, the magnetic resistance signal and the superconducting quantum interference signal respectively according to the detected temperature.

Optionally, the hall sensor further includes a first gain control circuit, configured to determine the intensity of the hall signal, and adjust the gain of the hall sensor to enhance the hall signal according to the intensity of the hall signal, so that the enhanced hall signal reaches a set signal-to-noise ratio.

Optionally, the first gain control circuit includes a peak detection circuit, a comparator, and a gain control element, where the peak detection circuit is configured to detect a peak value of the hall signal, the comparator is configured to compare the peak value with the reference signal to generate a gain control signal, and the gain control element is configured to adjust a gain of the hall sensor according to the gain control signal.

Optionally, the peak detection circuit includes a four-quadrant multiplier and a low-pass filter, the four-quadrant multiplier is configured to convert the hall signal into a unidirectional pulse signal, and the low-pass filter is configured to perform smoothing processing on the unidirectional pulse signal to obtain a smoothed pulse signal, so as to represent a peak value of the hall signal.

Optionally, the gain control element comprises a coupling capacitor, a resistor voltage division network and a filter circuit, wherein the coupling capacitor is used for coupling the gain control signal to the resistor voltage division network, the resistor voltage division network is used for performing voltage division processing on the gain control signal coupled to the coupling capacitor to obtain a voltage control signal, and the filter circuit is used for filtering the voltage control signal to adjust the gain of the Hall sensor.

Optionally, the magneto-resistive sensor has a plurality of measurement axes, each measurement axis is configured with a symmetrical bridge composed of four magneto-resistive resistors, each symmetrical bridge is connected with a preamplifier, so as to generate different magneto-resistive signal components based on the detection of the weak magnetic field at the position to be detected by the piling bridge along each measurement axis in different directions, amplify the corresponding magneto-resistive signal components by the preamplifier, obtain amplified magneto-resistive signal components, and send the amplified magneto-resistive signal components to the signal processing circuit to synthesize the different amplified magneto-resistive signal components to obtain the magneto-resistive signal.

Optionally, the signal processing circuit comprises a low noise amplifier, an analog-to-digital conversion circuit, a synchronous sampling circuit and a microprocessor, wherein the low noise amplifier is used for noise filtering of the different amplified magnetic resistance signal components, the analog-to-digital conversion circuit is used for analog-to-digital conversion of the different amplified magnetic resistance signal components after the noise process to obtain corresponding digital components, the synchronous sampling circuit is used for synchronous sampling of the digital components corresponding to the different amplified magnetic resistance signal components to obtain sampling components, and the microprocessor is used for vector synthesis of the sampling components subjected to synchronous sampling to obtain the magnetic resistance signals.

Optionally, the miniaturized superconducting quantum interferometer is wrapped with multiple layers of superconducting materials, an insulating layer is arranged in a gap between two adjacent layers of superconducting materials, each layer of superconducting material is communicated with a low-impedance path so as to dissipate interference of an external interference electromagnetic field on the weak magnetic field at the position to be detected, the insulating layer is made of aluminum oxide or silicon dioxide, and the low-impedance path is a superconducting wire.

Optionally, the weak magnetic field detection system further includes a magneto-electric sensor, where the magneto-electric sensor is configured to capture electromagnetic noise signals inside and outside the miniaturized superconducting quantum interferometer, amplify the electromagnetic noise signals with a preamplifier to increase a signal-to-noise ratio to a preset signal-to-noise ratio threshold, input the signal-to-noise ratio threshold into a notch filter to extract a noise band, and enable a signal generator to generate an inverse neutralization signal according to a phase of the noise band, so as to perform feedback cancellation on the electromagnetic noise signals, so as to eliminate the electromagnetic noise signals.

Optionally, the signal processing circuit further comprises a polarization emitter, a xenon atom bias magnetic field and a spin xenon atom nucleus, wherein the polarization emitter is used for generating rubidium atom polarization laser light and the xenon atom bias magnetic field, and is used for generating spin xenon atom nucleus in a dark state, so that the weak magnetic field at the position to be detected is spontaneously radiated through coupling between the rubidium atom polarization laser light and the spin xenon atom nucleus in the dark state to amplify the weak magnetic field at the position to be detected, and the Hall sensor, the magneto-resistance sensor and the miniaturized superconducting quantum interferometer are used for respectively detecting the amplified weak magnetic field at the position to be detected.

Optionally, the fusion module is specifically configured to perform temporal and spatial alignment on the received hall signal, the magneto-resistive signal, and the superconducting quantum interference signal, obtain calibrated magnetic field intensity components respectively, perform fourier transform on the calibrated magnetic field intensity components respectively to obtain a spectrum representation of each signal, perform multi-source fusion on the spectrum representation of each signal to obtain a multi-source fused spectrum representation, and convert the spectrum representation back to the time domain through inverse fourier transform to obtain a multi-source fused magnetic field signal.

Optionally, the signal analysis module is configured to receive the multi-source fusion magnetic field signal, and generate, according to the received multi-source fusion magnetic field signal, a magnetic field intensity value representing a weak magnetic field intensity at the position to be detected, where the magnetic field intensity value includes:

Fitting the multisource fusion magnetic field signal with a pre-established Hall sensor physical model, a magneto-resistive sensor physical model and a miniaturized superconducting quantum interferometer physical model respectively to obtain a corresponding first magnetic field intensity estimated value, a second magnetic field intensity estimated value and a third magnetic field intensity estimated value, and performing Bayesian estimation on the first magnetic field intensity estimated value, the second magnetic field intensity estimated value and the third magnetic field intensity estimated value to obtain a magnetic field intensity value representing the weak magnetic field intensity at the position to be detected.

Optionally, the signal analysis module respectively performs fitting based on a least square method on the multi-source fusion magnetic field signal and a pre-established hall sensor model, a magneto-resistance sensor model and a miniaturized superconducting quantum interferometer model to obtain corresponding first magnetic field intensity estimated value, second magnetic field intensity estimated value and third magnetic field intensity estimated value, performs bayesian estimation on the first magnetic field intensity estimated value, the second magnetic field intensity estimated value and the third magnetic field intensity estimated value based on expected performance description values of the hall sensor, the magneto-resistance sensor and the miniaturized superconducting quantum interferometer, and determines likelihood functions of the first magnetic field intensity estimated value, the second magnetic field intensity estimated value and the third magnetic field intensity estimated value relative to the multi-source fusion magnetic field signal respectively so as to calculate the magnetic field intensity value representing the weak magnetic field intensity at the position to be detected based on the likelihood functions and joint probability distribution among the first magnetic field intensity estimated value, the second magnetic field intensity estimated value and the third magnetic field intensity estimated value.

A weak magnetic field detection method, comprising:

the Hall sensor detects a weak magnetic field at a position to be detected to generate a Hall signal and sends the Hall signal;

the magnetic resistance sensor detects the weak magnetic field at the position to be detected to generate a magnetic resistance signal and sends the magnetic resistance signal;

Detecting the weak magnetic field at the position to be detected by a miniaturized superconducting quantum interferometer to generate a superconducting quantum interference signal and transmitting the superconducting quantum interference signal;

the fusion module in the signal processing circuit is respectively and electrically connected with the Hall sensor, the magnetic resistance sensor and the miniaturized superconducting quantum interferometer and is used for receiving the Hall signal, the magnetic resistance signal and the superconducting quantum interference signal, fusing the received Hall signal, the magnetic resistance signal and the superconducting quantum interference signal to obtain a multi-source fusion magnetic field signal and sending the multi-source fusion magnetic field signal;

and a signal analysis module in the signal processing circuit receives the multi-source fusion magnetic field signal and generates a magnetic field intensity value representing the weak magnetic field intensity at the position to be detected according to the received multi-source fusion magnetic field signal.

The invention provides a weak magnetic field detection system, which comprises a Hall sensor, a magnetic resistance sensor, a miniaturized superconducting quantum interferometer and a signal processing circuit, wherein the Hall sensor is used for detecting a weak magnetic field at a position to be detected to generate a Hall signal and transmitting the Hall signal, the magnetic resistance sensor is used for detecting the weak magnetic field at the position to be detected to generate a magnetic resistance signal and transmitting the magnetic resistance signal, the miniaturized superconducting quantum interferometer is used for detecting the weak magnetic field at the position to be detected to generate a superconducting quantum interference signal and transmitting the superconducting quantum interference signal, the signal processing circuit at least comprises a fusion module, and the signal processing circuit is electrically connected with the Hall sensor, the magnetic resistance sensor and the miniaturized superconducting quantum interferometer respectively and used for receiving the Hall signal, the magnetic resistance signal and the superconducting quantum interference signal, fusing the received Hall signal, the superconducting quantum interference signal to obtain a multi-source fusion magnetic field signal and transmitting the multi-source fusion magnetic field signal, and generating a magnetic field intensity value representing the intensity of the weak magnetic field at the position to be detected according to the received multi-source fusion magnetic field signal.

It can be seen that the above scheme of the application has the following technical advantages:

(1) The Hall sensor and the magnetic resistance sensor have high sensitivity, and can detect weak magnetic field change. Miniaturized superconducting quantum interferometers are known for their extremely high sensitivity and are capable of detecting extremely weak magnetic field signals. The signals of the sensors are fused through the fusion module, so that the sensitivity of the whole system can be further improved, and the more accurate detection of a weak magnetic field is realized.

(2) Each sensor has unique measurement principle and characteristic, and through fusing signals of various sensors, the advantages of the sensors can be fully utilized, the sensors are mutually complemented, and the overall measurement accuracy is improved. The fusion module can calibrate and weight distribution to signals of different sensors, so that the influence of measurement errors of a single sensor is eliminated or reduced, and the accuracy of measurement results is improved.

(3) Different sensors have different sensitivity and anti-interference capabilities to different types of environmental disturbances. By fusing signals of multiple sensors, the influence of environmental interference on a single sensor can be reduced, and the stability and reliability of the system are improved.

(4) Hall sensors and magnetoresistive sensors generally have a high response speed and can rapidly detect a change in magnetic field. Once the miniaturized superconducting quantum interferometer reaches a stable working state, the response speed is very high. The fusion module and the signal analysis module in the signal processing circuit can realize rapid processing and analysis of the multi-source signals, thereby ensuring that the whole system has a faster response speed.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application, are incorporated in and constitute a part of this specification. The drawings and their description are illustrative of the application and are not to be construed as unduly limiting the application. In the drawings:

Fig. 1 is a schematic flow chart of a weak magnetic field detection system according to an embodiment of the application.

Detailed Description

In order that those skilled in the art will better understand the present application, a detailed description of embodiments of the present application will be provided below, with reference to the accompanying drawings, wherein it is apparent that the described embodiments are only some, but not all, embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application.

Fig. 1 is a schematic flow chart of a weak magnetic field detection system according to an embodiment of the application. As shown in fig. 1, it includes:

A signal processing circuit comprising at least:

(5) The Hall sensor and the magnetic resistance sensor have high sensitivity, and can detect weak magnetic field change. Miniaturized superconducting quantum interferometers are known for their extremely high sensitivity and are capable of detecting extremely weak magnetic field signals. The signals of the sensors are fused through the fusion module, so that the sensitivity of the whole system can be further improved, and the more accurate detection of a weak magnetic field is realized.

(6) Each sensor has unique measurement principle and characteristic, and through fusing signals of various sensors, the advantages of the sensors can be fully utilized, the sensors are mutually complemented, and the overall measurement accuracy is improved. The fusion module can calibrate and weight distribution to signals of different sensors, so that the influence of measurement errors of a single sensor is eliminated or reduced, and the accuracy of measurement results is improved.

(7) Different sensors have different sensitivity and anti-interference capabilities to different types of environmental disturbances. By fusing signals of multiple sensors, the influence of environmental interference on a single sensor can be reduced, and the stability and reliability of the system are improved.

(8) Hall sensors and magnetoresistive sensors generally have a high response speed and can rapidly detect a change in magnetic field. Once the miniaturized superconducting quantum interferometer reaches a stable working state, the response speed is very high. The fusion module and the signal analysis module in the signal processing circuit can realize rapid processing and analysis of the multi-source signals, thereby ensuring that the whole system has a faster response speed.

Therefore, the technical scheme based on the first gain control circuit has the following technical advantages:

(1) The first gain control circuit can dynamically adjust the gain of the sensor according to the intensity of the Hall signal. When the hall signal is weak, the signal strength can be effectively enhanced by increasing the gain, while the noise level is maintained or reduced, thereby improving the signal-to-noise ratio of the signal. The high signal-to-noise ratio means that useful information in the signal is more prominent and noise interference is less, so that the detection accuracy and reliability of the whole system are improved.

(2) By adjusting the gain, the first gain control circuit can optimize the dynamic range of the hall sensor. This means that the sensor can more effectively cover magnetic field signals of different strengths, both weak and strong, with proper processing. This is particularly important for detecting weak magnetic fields in complex environments, as such environments may contain magnetic field signals of different strengths.

(3) The strength of the magnetic field signal may vary due to changes in environmental conditions and the object to be detected. The first gain control circuit is capable of responding to these changes in real time and adjusting the gain accordingly to ensure that the system operates stably under a variety of conditions. The self-adaptive capacity improves the robustness of the system, so that the system is more suitable for weak magnetic field detection in complex and changeable environments.

(4) False positives and false negatives are common problems in low-field detection. The Hall signal is enhanced and optimized through the first gain control circuit, so that the system can be ensured to more accurately identify the real magnetic field signal, and the possibility of false alarm and false omission is reduced. This is critical for application scenarios requiring high precision detection.

(5) The hall signal enhanced by the first gain control circuit has a higher signal-to-noise ratio and a better dynamic range, which makes subsequent signal processing and analysis simpler and more efficient. The fusion module and the signal analysis module in the signal processing circuit can more easily process the signals and generate more accurate magnetic field intensity values.

For this purpose, based on a first gain control circuit comprising a peak detection circuit, a comparator, a gain control element, there are the following technical advantages:

(1) Through the peak detection circuit, the system can capture the peak value of the Hall signal in real time. The comparator then compares the detected peak value with a reference signal to determine whether the gain needs to be adjusted. This way it is ensured that the adjustment of the gain is based on the actual strength of the current signal, enabling an adaptive gain control.

(2) The gain control element dynamically adjusts the gain of the hall sensor according to the gain control signal to ensure that the hall signal reaches a preset signal-to-noise level. Such real-time adjustment can effectively amplify weak signals while limiting the increase of noise, thereby greatly improving signal quality and facilitating more accurate detection of weak magnetic fields.

(3) The adaptive gain adjustment ensures that the system works in an optimal state regardless of the change in magnetic field strength. This helps to optimize the overall performance of the system, especially when dealing with complex and dynamically changing magnetic field environments.

(4) By automatically adjusting the gain, the system no longer needs to be manually adjusted or calibrated, thereby simplifying the system design and maintenance process. Meanwhile, the risk of human errors is reduced, and the reliability and stability of the system are improved.

(5) In complex or varying environments, the magnetic field strength may vary drastically. The introduction of the first gain control circuit enables the system to respond quickly to these changes and automatically adjust the gain to maintain optimum performance. This capability enhances the robustness of the system making it more suitable for low magnetic field detection in harsh environments.

For this purpose, the peak detection circuit based on the one comprising a four-quadrant multiplier and a low-pass filter has the following technical advantages:

(1) The four-quadrant multiplier can convert the hall signal into a unidirectional pulsating signal. This conversion helps to simplify the subsequent signal processing steps, since unidirectional ripple signals are easier to resolve and process in terms of waveform and amplitude.

(2) The hall signal may contain noise and interference and the direct detection of the peak may be affected by these factors. After being converted into a unidirectional pulsation signal through the four-quadrant multiplier, the signal is subjected to smoothing treatment through a low-pass filter, so that noise and interference can be effectively removed, and the peak detection precision is improved.

(3) The low-pass filter performs smoothing on the unidirectional pulsation signal to obtain a smoothed pulse signal, and the signal more accurately reflects the peak value of the Hall signal. The smoothing process can further reduce the effects of noise and interference, making peak detection more stable and reliable.

(4) By accurately detecting the peak value of the hall signal, the first gain control circuit can accurately adjust the gain of the hall sensor based on the peak value. This helps ensure that the system will work in an optimal manner under a variety of conditions, improving the reliability and stability of the system.

(5) The optimization of the peak detection circuit enables the system to more accurately evaluate the strength of the hall signal and adjust the gain as needed. This helps ensure that the system maintains high sensitivity and accuracy even in low magnetic field environments, thereby optimizing the overall performance of the system.

(6) The smooth pulse signal generated by the peak detection circuit is used as the peak value representative of the Hall signal, so that the subsequent signal processing and analysis become simpler and more efficient. The fusion module and the signal analysis module in the signal processing circuit can more easily process the signals and generate more accurate magnetic field intensity values.

For this purpose, the gain control element based on the above-mentioned coupling capacitor, resistor-divider network and filter circuit has the following technical advantages:

(1) The resistor voltage dividing network can divide the gain control signal transmitted by the coupling capacitor to obtain an accurate voltage control signal. This voltage dividing process ensures the accuracy of the voltage control signal, so that the gain of the hall sensor can be accurately adjusted.

(2) The filter circuit filters the voltage control signal, so that noise and interference in the signal can be removed, and the stability of the signal is improved. This further ensures the accuracy and stability of the hall sensor gain adjustment.

(3) The rapid charge-discharge characteristic of the coupling capacitor enables the gain control signal to be rapidly transferred to the resistor divider network, and rapid response is achieved. Meanwhile, the processing speed of the resistor voltage division network and the filter circuit is relatively high, and the gain of the Hall sensor can be quickly adjusted so as to meet the application scene with high real-time requirements.

(4) The amplitude of the voltage control signal can be conveniently changed by adjusting the resistance value of the resistor in the resistor voltage division network, so that the gain of the Hall sensor can be flexibly adjusted. The design ensures that the system has stronger expansibility and flexibility and can adapt to the requirements of different application scenes.

(5) The resistor voltage division network and the filter circuit are solid electronic components, and have high reliability and stability. They can work stably under various environmental conditions, ensuring the accuracy and reliability of the gain adjustment of the hall sensor.

For this purpose, the magneto-resistive sensor with a symmetrical bridge of four magneto-resistive resistors is based on the above-mentioned arrangement with a plurality of measuring axes, each measuring axis having the following technical advantages:

In a weak magnetic field detection system, by adopting a magneto-resistance sensor, the following remarkable technical advantages are brought by configuring a symmetrical bridge consisting of four magneto-resistance resistors for each measuring axis and connecting a preamplifier for signal amplification:

(1) The magnetoresistive sensor has a plurality of measuring axes set, each of which is capable of independently detecting a change in the magnetic field in a particular direction. The multidirectional detection capability enables the system to comprehensively capture magnetic field information, and improves the accuracy and the comprehensiveness of detection.

(2) The symmetrical bridge structure improves the sensitivity of the sensor to magnetic field variations by careful design of the magnetoresistive configuration. This enables the sensor to detect weak magnetic field changes, providing the possibility of weak magnetic field detection.

(3) Each symmetrical bridge connected preamplifier can amplify weak magneto-resistive signal components. This not only increases the amplitude of the signal, but also improves the signal-to-noise ratio of the signal, making subsequent signal processing easier and more accurate.

(4) The preamplifier is generally designed to be of a low noise type, and is capable of suppressing amplification of noise while amplifying a signal. This helps to reduce noise interference in the system and improve detection accuracy.

(5) The signal processing circuit can perform synthesis processing on amplified magnetic resistance signal components on different measuring axes to obtain a final magnetic resistance signal. The synthesis processing can comprehensively consider magnetic field information in multiple directions to obtain a more comprehensive and accurate detection result.

For this purpose, the signal processing circuit based on the microprocessor comprises a low noise amplifier, an analog-to-digital conversion circuit, a synchronous sampling circuit and a microprocessor has the following technical advantages:

(1) The low-noise amplifier can effectively filter noise of different amplified magnetic resistance signal components, and improves the signal-to-noise ratio of signals. This is particularly important for weak magnetic field detection, as weak signals are more susceptible to noise interference. By reducing noise, the accuracy and reliability of detection can be improved.

(2) The analog-to-digital conversion circuit converts the analog signals subjected to noise filtering into digital signals, and provides a basis for subsequent digital processing. The digital processing has higher flexibility and accuracy, and can process and analyze signals more accurately.

(3) The synchronous sampling circuit ensures synchronous sampling of the digital components of the different amplified magnetoresistive signal components, thereby preserving the temporal relationship between the components. This is important for subsequent vector synthesis, since only accurate time synchronization ensures the accuracy of the synthesis result.

(4) The microprocessor is responsible for vector synthesis of the sampled components of the synchronous samples to obtain the final magneto-resistive signal. The vector synthesis can comprehensively consider signal components in different directions to obtain more accurate magnetic field intensity and direction information. This accuracy is critical for low magnetic field detection because it can provide more accurate magnetic field measurements.

(5) By adopting the signal processing circuit, the performance of the whole weak magnetic field detection system is remarkably improved. The sensitivity, resolution, measurement precision, response time and other key indexes of the system are improved, so that the requirements of practical application can be better met.

For this purpose, the miniaturized superconducting quantum interferometer based on the above-mentioned multilayer superconducting material externally wrapped has the following technical advantages:

(1) The design that the outside of miniaturized superconducting quantum interference device (SQUID) wraps up multilayer superconducting material to set up the insulating layer in adjacent two-layer superconducting material clearance has brought following apparent technical advantage:

(2) The design of the multi-layer superconducting material forms an effective electromagnetic shielding layer, and can remarkably reduce the interference of an external electromagnetic field on the internal SQUID. This is important to improve the sensitivity and accuracy of SQUIDs in low magnetic field detection.

(3) The electromagnetic shielding effect is further enhanced by an insulating layer (such as alumina or silica) between two adjacent layers of superconducting material. These insulating materials have good insulating properties, and can prevent current leakage between superconducting layers, thereby ensuring stable operation of SQUID.

(4) Each layer of superconducting material communicates with a low impedance path (e.g., superconducting wire) that provides a path for the external interfering electromagnetic fields to dissipate. When an external electromagnetic field acts on the superconducting layer, the induced current generated is rapidly dissipated through the low impedance path, thereby reducing the impact on the SQUID.

(5) Improving the system performance:

(6) By reducing external electromagnetic field interference, the design significantly improves SQUID performance in low magnetic field detection. The SQUID can more accurately measure weak magnetic field change, and provides a powerful tool for the research in the fields of biomedicine, material science and the like.

(7) By adopting the design in the miniaturized SQUID, the high sensitivity characteristic of the SQUID is maintained, and the SQUID is more convenient to integrate and deploy in various environments. This provides the possibility to extend the application range of SQUIDs.

For this purpose, the weak magnetic field detection system based on the magnetoelectric sensor has the following technical advantages:

(1) The magneto-electric sensor is capable of capturing electromagnetic noise signals inside and outside a miniaturized superconducting quantum interference device (SQUID). These noise signals are amplified by a pre-amplifier so that the signal-to-noise ratio (SNR) is increased to a preset SNR threshold. A higher signal-to-noise ratio means that the detected signal is clearer, facilitating subsequent signal processing and analysis.

(2) The amplified electromagnetic noise signal is input to a notch filter, which can accurately extract the noise band. The accurate extraction capability enables the system to conduct targeted processing aiming at specific noise frequency bands, and improves the accuracy and efficiency of processing.

(3) The signal generator is capable of generating a corresponding inverse neutralisation signal in dependence on the phase of the extracted noise band. Such an inverted neutralizing signal is opposite in phase to the original noise signal, and when they are superimposed, they can cancel each other out, thereby effectively eliminating the electromagnetic noise signal.

(4) By generating an inverted neutralizing signal and performing feedback cancellation on the electromagnetic noise signal, the system can significantly reduce or even eliminate the influence of electromagnetic noise on the detection of a weak magnetic field. The feedback offset mechanism improves the anti-interference capability of the system, so that the detection result is more accurate and reliable.

For this purpose, the signal processing circuit based on the polarized emitter and xenon atom bias magnetic field has the following technical advantages:

(1) The coupling between rubidium atom polarized laser generated by the polarized emitter and spin xenon atomic nuclei in a dark state realizes spontaneous radiation amplification of a weak magnetic field at a position to be detected. The amplification mechanism can remarkably improve the signal intensity of a weak magnetic field, so that a subsequent sensor (such as a Hall sensor, a magnetic resistance sensor and a miniaturized superconducting quantum interferometer) can more accurately detect the magnetic field change.

(2) Amplification of the weak magnetic field directly improves the sensitivity of the detection system. The Hall sensor, the magnetic resistance sensor, the miniaturized superconducting quantum interferometer and other sensors can capture the amplified weak magnetic field signal, so that the response capability to the weak magnetic field change is improved.

(3) At the same time as the weak magnetic field signal is amplified, the interference with respect to noise is reduced due to the increase in signal strength. This means that the system can more effectively extract useful magnetic field signals under the same noise environment, and the influence of noise on the detection result is reduced.

(4) By improving detection sensitivity and reducing noise interference, the system can be applied to a wider range of fields such as biomedicine, geological exploration, nondestructive detection and the like. The method can be used for researching brain activities, nerve magnetic fields and the like in the biomedical field, detecting the magnetic field characteristics of underground substances in the geological exploration field and detecting the physical characteristics of materials such as strength, density and the like in the nondestructive detection field.

(5) The system is significantly improved in stability and reliability due to the use of advanced signal processing techniques (e.g., spontaneous emission amplification) and high quality sensors (e.g., miniaturized superconducting quantum interferometers). Even in complex and changeable environments, higher detection precision and stability can be maintained.

(6) By amplifying and accurately detecting the weak magnetic field, the system can realize high-precision magnetic field measurement. This is of great importance for experimental and application scenarios (such as precision measurement, quantum computation, etc.) where precise control of the magnetic field environment is required.

Therefore, based on the fusion module, the method has the following technical advantages:

(1) The fusion module can ensure the consistency of the received Hall signal, the received magnetic resistance signal and the received superconducting quantum interference signal in time and space. This alignment process is the basis for a subsequent accurate fusion, which eliminates errors that may be introduced due to different sensor response times and positional differences.

(2) After alignment, the fusion module calibrates the signals to obtain calibrated magnetic field intensity components. This step can further reduce errors and improve the accuracy of the magnetic field strength measurement.

(3) Fourier transforming the calibrated magnetic field strength components may result in a spectral representation of each signal. The fourier transform is capable of transforming the signal from the time domain to the frequency domain, helping to analyze the frequency characteristics of the signal. In weak magnetic field detection, this helps to identify and analyze different frequency components in the magnetic field signal.

(4) After the spectrum representation of each signal is obtained, the fusion module carries out multi-source fusion to obtain the spectrum representation of the multi-source fusion. The information from different sensors is fully utilized in the step, and the comprehensiveness and accuracy of the magnetic field signals are improved through fusion. The multi-source fusion technique is capable of integrating data from multiple sensors, reducing the limitations that may exist for a single sensor.

(5) And converting the multi-source fused spectrum representation back to the time domain through inverse Fourier transform to obtain a multi-source fused magnetic field signal. This step converts the fused frequency domain signal back into a time domain signal that is easier to understand and analyze, providing a basis for subsequent magnetic field analysis and application.

(6) The fusion module remarkably improves the precision and reliability of weak magnetic field detection through a multi-source data fusion technology. The fusion of the multi-source data can fully utilize the information from different sensors, reduce errors and uncertainty, and provide more accurate and reliable results for weak magnetic field detection.

(7) The fusion module can also enhance the robustness of the system. When a certain sensor fails or data is abnormal, the fusion module can maintain the normal operation of the system by means of the data of other sensors, so that the stability and the reliability of the system are improved.

Therefore, the signal analysis module adopts the method of fitting the multisource fusion magnetic field signal and the physical model in the weak magnetic field detection system and combining Bayesian estimation, so that the following remarkable technical advantages are brought:

(1) By fitting the multisource fusion magnetic field signals with the pre-established physical models of the Hall sensor, the magnetic resistance sensor and the miniaturized superconducting quantum interferometer, the response of each sensor to the weak magnetic field can be estimated more accurately. The fitting method based on the physical model can reduce the influence of environmental noise and sensor errors on the measurement result, thereby improving the measurement accuracy.

(2) The data of a plurality of sensors are fused, so that the advantages of different sensors in measurement range and precision and the complementarity of the sensors under different environmental conditions can be fully utilized. The multi-source data fusion method can provide more comprehensive and accurate magnetic field information, so that the final magnetic field intensity value is more reliable.

(3) The magnetic field intensity values estimated by different sensors are comprehensively processed by using a Bayesian estimation method, so that a more robust result can be obtained. The Bayesian estimation can consider the confidence coefficient and the correlation of different estimation values, so that an optimal magnetic field intensity value which accords with the actual situation is obtained. This method is particularly effective for dealing with complex, uncertain magnetic field environments.

(4) The method of the signal analysis module is applicable to detection of different types of weak magnetic fields, namely a static magnetic field and a dynamic magnetic field, and can adapt to different application scenes by adjusting parameters of a physical model and Bayesian estimation. This flexibility allows for a wide range of applicability of the module.

(5) By means of multi-source data fusion and Bayesian estimation, the module can reduce the influence of single sensor faults on the overall performance of the system. Even if a certain sensor has faults or abnormal data, the system can still maintain normal operation by means of the data of other sensors, so that the reliability and stability of the system are improved.

For this reason, the signal analysis module processes the multisource fusion magnetic field signal by adopting a method based on fitting of a least square method and Bayesian estimation, and determines a magnetic field strength value by combining with an expected performance description value of the sensor, and has the following technical advantages:

(1) Through least square fitting, the relation between the multisource fusion magnetic field signals and each sensor model can be described more accurately, and therefore more accurate magnetic field strength estimated values are obtained. The method can reduce errors caused by model mismatch or data noise and improve measurement accuracy.

(2) In the Bayesian estimation process, expected performance description values of Hall sensors, magnetoresistive sensors and miniaturized superconducting quantum interferometers are considered. The description values reflect the performance characteristics of the sensors under different conditions, and can help the system to evaluate the reliability and the weight of each sensor estimated value more accurately, so that more accurate magnetic field intensity values are obtained.

(3) By combining the data of a plurality of sensors, the advantages of different sensors in measurement range and precision and the complementarity of the sensors under different environmental conditions can be fully utilized. The data of a plurality of sensors can be fused into a more reliable and more accurate magnetic field intensity value through least square fitting and Bayesian estimation, so that the overall performance of the system is improved.

(4) The Bayesian estimation method can consider the confidence coefficient and the correlation of different estimation values, and obtain the optimal magnetic field intensity value by calculating likelihood functions and joint probability distribution. The method is particularly effective for processing complex and uncertain magnetic field environments, and can improve the robustness and stability of the system.

(5) The method is suitable for detecting different types of weak magnetic fields, namely a static magnetic field or a dynamic magnetic field, and can adapt to different application scenes by adjusting model parameters and Bayesian estimated parameters. This flexibility allows for a wide range of applicability of the system.

(6) If new sensors need to be added or existing sensors need to be retrofitted, only new models need to be built and incorporated into the fitting and estimation process. Meanwhile, due to the adoption of a fitting method based on a model, the maintenance of the system is relatively simple, and the model is only required to be updated and calibrated regularly.

The embodiment of the application also provides a weak magnetic field detection method, which comprises the following steps:

Exemplary descriptions of the steps in the above method can be found in the description of the above system.

It should be noted that the system can be manufactured based on a micro-electro-mechanical system (MEMS) technology, and meanwhile, through three-dimensional packaging and stacking technology, a plurality of sensors, signal processing circuits and even an energy supply unit (such as a micro battery or an energy collector) can be integrated together in a high-efficiency and compact manner, so as to form a highly integrated micro system, which is suitable for wearable applications.

The above description is only illustrative of the preferred embodiments of the present application and of the principles of the technology employed. It will be appreciated by persons skilled in the art that the scope of the application referred to in the present application is not limited to the specific combinations of the technical features described above, but also covers other technical features formed by any combination of the technical features described above or their equivalents without departing from the inventive concept described above. Such as the above-mentioned features and the technical features disclosed in the present application (but not limited to) having similar functions are replaced with each other.

Claims

1. A weak magnetic field detection system, comprising:

A Hall sensor is used to detect a weak magnetic field at a position to be detected to generate and send a Hall signal;

A magnetoresistive sensor, used for detecting a weak magnetic field at the position to be detected to generate and send a magnetoresistive signal;

A miniaturized superconducting quantum interference device, used to detect the weak magnetic field at the position to be detected to generate and send a superconducting quantum interference signal;

The signal processing circuit comprises at least:

A fusion module, electrically connected to the Hall sensor, the magnetoresistive sensor, and the miniaturized superconducting quantum interference device, respectively, for receiving the Hall signal, the magnetoresistive signal, and the superconducting quantum interference signal, and fusing the received Hall signal, the magnetoresistive signal, and the superconducting quantum interference signal to obtain a multi-source fused magnetic field signal and send it;

A signal analysis module, used for receiving the multi-source fusion magnetic field signal, and generating a magnetic field strength value representing the weak magnetic field strength at the position to be detected according to the received multi-source fusion magnetic field signal;

The Hall sensor further includes a first gain control circuit, which is used to determine the strength of the Hall signal and, according to the strength of the Hall signal, adjust the gain of the Hall sensor to enhance the Hall signal so that the enhanced Hall signal reaches a set signal-to-noise ratio;

The first gain control circuit includes a peak detection circuit, a comparator, and a gain control element. The peak detection circuit is used to detect the peak value of the Hall signal. The comparator is used to compare the peak value with a reference signal to generate a gain control signal. The gain control element is used to adjust the gain of the Hall sensor according to the gain control signal.

Wherein, the peak detection circuit includes a four-quadrant multiplier and a low-pass filter, the four-quadrant multiplier is used to convert the Hall signal into a unidirectional pulse signal, and the low-pass filter is used to smooth the unidirectional pulse signal to obtain a smoothed pulse signal to represent the peak value of the Hall signal;

Among them, the gain control element includes: a coupling capacitor, a resistor voltage divider network, and a filter circuit. The coupling capacitor is used to couple the gain control signal to the resistor voltage divider network. The resistor voltage divider network is used to perform voltage division processing on the gain control signal coupled thereto to obtain a voltage control signal. The filter circuit filters the voltage control signal to adjust the gain of the Hall sensor.

2. The weak magnetic field detection system according to claim 1 is characterized in that the weak magnetic field detection system also includes: a temperature sensor for detecting the temperature at the detection position, so as to compensate the Hall signal, the magnetoresistance signal, and the superconducting quantum interference signal according to the detected temperature.

3. The weak magnetic field detection system according to claim 2 is characterized in that the magnetoresistive sensor has a plurality of set measuring axes, each measuring axis is configured with a symmetrical bridge composed of four magnetoresistive resistors, and each of the symmetrical bridges is connected to a preamplifier, so as to detect the weak magnetic field at the position to be detected in different directions along each measuring axis based on the symmetrical bridge to generate different magnetoresistive signal components, and the corresponding magnetoresistive signal components are amplified by the preamplifier to obtain amplified magnetoresistive signal components, and sent to the signal processing circuit to synthesize the different amplified magnetoresistive signal components to obtain the magnetoresistive signal and send it.

4. The weak magnetic field detection system according to claim 3 is characterized in that the signal processing circuit includes: a low-noise amplifier, an analog-to-digital conversion circuit, a synchronous sampling circuit, and a microprocessor, wherein the low-noise amplifier is used to filter the noise of the different amplified magnetoresistance signal components, the analog-to-digital conversion circuit is used to perform analog-to-digital conversion on the different amplified magnetoresistance signal components after noise filtering to obtain corresponding digital components, the synchronous sampling circuit is used to synchronously sample the digital components corresponding to the different amplified magnetoresistance signal components to obtain sampling components, and the microprocessor is used to perform vector synthesis on the synchronously sampled sampling components to obtain the magnetoresistance signal.

5. The weak magnetic field detection system according to claim 1 is characterized in that the outside of the miniaturized superconducting quantum interference device is wrapped with multiple layers of superconducting material, an insulating layer is arranged in the gap between two adjacent layers of superconducting material, and each layer of superconducting material is connected to a low-impedance path to dissipate the interference of external interfering electromagnetic fields on the weak magnetic field at the position to be detected, the material of the insulating layer is aluminum oxide or silicon dioxide, and the low-impedance path is a superconducting wire.

6. The weak magnetic field detection system according to claim 5 is characterized in that the weak magnetic field detection system also includes a magnetoelectric sensor, which is used to capture electromagnetic noise signals inside and outside the miniaturized superconducting quantum interference device, and amplify the electromagnetic noise signal through a preamplifier to increase the signal-to-noise ratio to a preset signal-to-noise ratio threshold, so as to input it into a notch filter for noise band extraction, and enable a signal generator to generate an anti-phase neutralization signal according to the phase of the noise band to feedback and offset the electromagnetic noise signal to eliminate the electromagnetic noise signal.

7. The weak magnetic field detection system according to claim 1 is characterized in that the signal processing circuit also includes: a polarization transmitter for generating rubidium atom polarization laser, and a xenon atom bias magnetic field for generating spinning xenon nuclei in a dark state, so as to spontaneously radiate the weak magnetic field at the position to be detected through the coupling between the rubidium atom polarization laser and the spinning xenon nuclei in the dark state to amplify the weak magnetic field at the position to be detected, so that the Hall sensor, the magnetoresistive sensor, and the miniaturized superconducting quantum interference device respectively detect the amplified weak magnetic field at the position to be detected.

8. The weak magnetic field detection system according to claim 1 is characterized in that the fusion module is specifically used to align the received Hall signal, the magnetoresistance signal, and the superconducting quantum interference signal in time and space to obtain calibrated magnetic field intensity components respectively, and perform Fourier transform on the calibrated magnetic field intensity components respectively to obtain the spectrum representation of each signal, perform multi-source fusion on the spectrum representation of each signal to obtain a multi-source fused spectrum representation, and convert the spectrum representation back to the time domain through inverse Fourier transform to obtain a multi-source fused magnetic field signal.

9. A weak magnetic field detection method using the weak magnetic field detection system according to any one of claims 1 to 8, characterized in that it comprises:

The Hall sensor detects the weak magnetic field at the position to be detected to generate and send a Hall signal;

The magnetoresistive sensor detects the weak magnetic field at the position to be detected to generate a magnetoresistive signal and sends it;

The miniaturized superconducting quantum interference device detects the weak magnetic field at the position to be detected to generate and send a superconducting quantum interference signal;

The fusion module in the signal processing circuit is electrically connected to the Hall sensor, the magnetoresistive sensor, and the miniaturized superconducting quantum interference device, respectively, and is used to receive the Hall signal, the magnetoresistive signal, and the superconducting quantum interference signal, and fuse the received Hall signal, the magnetoresistive signal, and the superconducting quantum interference signal to obtain a multi-source fused magnetic field signal and send it;

The signal analysis module in the signal processing circuit receives the multi-source fusion magnetic field signal, and generates a magnetic field strength value representing the weak magnetic field strength at the position to be detected based on the received multi-source fusion magnetic field signal.