162 results about "Very low frequency" patented technology

The invention discloses a low ionosphere intelligent inversion method based on VLF radio wave detection, and the method comprises the steps: collecting ground-based very-low-frequency wave amplitude data, defining a gated cycle unit network objective function as an optimized performance index, and employing a mean square error as the objective function; and carrying out dynamic position updating by adopting a whale optimization algorithm, setting a double-stop criterion, and stopping iterative training to obtain an optimal model when the maximum number of iterations or a verification error convergence threshold value is reached. The calculation result of the LWPC model is used as a training set, the GRU network is used as an objective function estimator from foundation very low frequency data to low ionosphere parameters, the inversion method can accurately approach a real model, and the algorithm performance is effective and feasible and is remarkably improved compared with an existing model.

The invention relates to the technical field of underwater navigation and positioning, and particularly discloses a wide-area very-low-frequency radio navigation and underwater sound combined underwater navigation and positioning method, which comprises the following steps that: a very-low-frequency navigation transmitting station transmits a very-low-frequency radio navigation time service signal; the semi-submersible acoustic beacon receives a very-low-frequency radio navigation time service signal; performing position calibration and time synchronization; the semi-submersible acoustic beacon emits an underwater acoustic navigation signal, and the underwater carrier calculates the three-dimensional coordinates of the underwater carrier according to the received underwater acoustic navigation signal. According to the invention, a shore-based very-low-frequency radio navigation and underwater sound combined navigation mode is adopted, and a very-low-frequency radio navigation time service signal has a certain underwater entry depth, so that the problem of time synchronization between semi-submersible acoustic beacons is solved, and auxiliary calibration of the positions of the semi-submersible acoustic beacons is provided; the semi-submersible acoustic beacon emits an underwater navigation signal to realize navigation and positioning of a deepwater underwater carrier, and reliable navigation service with wide area coverage, high precision and low power consumption is provided for the underwater carrier.

The invention relates to the technical field of thunder and lightning signal sampling, and discloses a GAN-based thunder and lightning very-low-frequency electromagnetic wave signal up-sampling method, a terminal and a medium. The method comprises the following steps: preprocessing a lightning very-low-frequency low-sampling signal and a real high-sampling signal; constructing a generative adversarial network; the generator is used for extracting initial features from the low-sampling signals and performing residual enhancement, then mapping low-sampling features after residual enhancement to a high-sampling dimension through a feature-guided dynamic interpolation mechanism, and performing correction and signal mapping on intermediate features after interpolation to obtain reconstructed signals matched with a target high-sampling rate; the discriminator is used for reconstructing the authenticity probability of the signal; after a generator and a discriminator are jointly trained by adopting an alternative updating mode of discriminator loss and generator loss, a newly input low sampling signal is preprocessed, and a corresponding reconstruction signal is output through the generator. According to the invention, accurate reconstruction from a lightning very-low-frequency low-sampling signal to a high-sampling signal is realized.

The invention provides a method and a system for improving the receiving bandwidth of a very-low-frequency atom magnetometer. The method comprises the following steps of: polarizing alkali metal atoms in an atom gas chamber along the direction of driving laser by using the driving laser; an external magnetic field at the air chamber is compensated through a three-axis magnetic coil and a three-axis magnetic sensor, a zero field environment is provided, and a main magnetic field B is applied by the coil in the direction of driving light; detecting the precession of the spin projection signal of the polarized atom in the x direction by using the detection laser in the x direction; an external very-low-frequency signal interacts with atoms polarized in the z direction to enable the atoms to generate precession signals on the xOy plane, and therefore the external very-low-frequency signal is detected by detection light. After detection optical signals are collected, the control system feeds back the signals to the atom ensemble through the coil in a damping magnetic field mode, the bandwidth of the system is expanded by adjusting feedback parameters, and meanwhile the sensitivity is kept unchanged. According to the technical scheme, the technical problem that high sensitivity and high bandwidth cannot be achieved at the same time in a very-low-frequency atom magnetometer in the prior art is solved.

The invention discloses a self-adaptive multi-unit very-low-frequency phased-array antenna system and a control method thereof, and the system comprises an antenna unit which comprises a vertical radiator and a top loading capacitor network erected on the vertical radiator; the central signal processing and distributing unit comprises parallel signal channels with the same number as the antenna units, and the signal channels are integrated with signal adjusting devices; the input end of the feed network is connected to the central signal processing and distributing unit, and the output end is connected to the vertical radiator to transmit a radio frequency excitation signal; the plurality of feedback sensors are arranged in the feed network and are used for monitoring electrical state parameters of signals flowing to the antenna units; the central control unit is connected with the feedback sensor and the central signal processing and distributing unit, monitors electrical state parameters based on the feedback sensor, and controls the signal adjusting device to adjust the amplitude and phase of the excitation signal. According to the invention, the beam forming and directional communication capabilities of the very-low-frequency antenna are realized, and the flexibility of an antenna system is expanded.

The invention discloses a VLF propagation signal prediction method based on a three-dimensional finite element and a neural network, and belongs to the technical field of electronic communication. The method comprises the following steps: firstly, constructing a geosphere-ionosphere waveguide model based on a three-dimensional frequency domain finite element method, and solving by using a multi-grid method to improve the operation efficiency; secondly, constructing a VLF signal propagation data set of a plurality of known paths at one time based on a three-dimensional frequency domain finite element method; then, constructing a neural network model reflecting a mapping relation between an ionized layer electron density parameter and a VLF wave characteristic based on the data set; then, obtaining electron density distribution on a plurality of known paths based on neural network inversion; and finally, carrying out inversion by adopting an inverse square weight formula to obtain electron density distribution on the to-be-solved path. According to the method, the VLF signal transmission characteristics on multiple paths can be simulated at a time, the workload of modeling simulation is effectively reduced, and the method is suitable for the fields of inversion of a multi-path electron density parameter model, prediction of very low frequency wave propagation and the like.

The invention provides a self-biased very-low-frequency mechanical transmitting antenna driven by piezoelectricity and a preparation method of the self-biased very-low-frequency mechanical transmitting antenna. The preparation method comprises the following steps: step 1, preparing a piezoelectric ceramic material; step 2, cutting and slotting; thirdly, resin is poured; step 4, cutting the layer sheets; step 5, packaging; step 6, polarization treatment; step 7, preparing a bonding layer; and 8, hot-pressing and compounding. Compared with an existing magnetoelectric antenna, the self-biased very-low-frequency mechanical transmitting antenna has the advantages of being self-biased, high in piezoelectric property, miniaturized, free of extra noise sources and electromagnetic interference and the like, has the advantages of being high in stress transmission efficiency, small in ohmic loss and the like, can meet the requirement for miniaturization of the magnetoelectric mechanical antenna, is easy to form a large-scale array, and is suitable for large-scale popularization and application. The magnetic emission performance under zero bias is improved, and the low-frequency communication effect is achieved.

Piezoelectric antennas may include a tuning mechanism. The tuning mechanism may adjust the operation frequency of the antennas and compensate the frequency drifts due to environmental effects on the piezoelectric materials and the other potential circuitry. The tuning mechanism may also modulate signal for communication purposes. A transmitter circuit may control the tuning mechanism. A transmitter circuit may control the tuning mechanism. The transmitter circuit may independently control multiple of the tuning mechanism, where the piezoelectric antennas are arranged in an array.

The invention belongs to the technical field of thunder and lightning signal noise reduction, and particularly relates to a noise reduction method and noise reduction system for very low frequency thunder and lightning signals and a storage medium. The noise reduction method comprises the steps of obtaining a plurality of position points of a current mixed lightning signal in a dung beetle algorithm after the mixed lightning signal is obtained; after a position point corresponding to the minimum envelope entropy in the current mixed lightning signal is calculated based on a VMD algorithm, the abscissa and the ordinate of the position point corresponding to the minimum envelope entropy are respectively recorded as an optimal decomposition mode number and an optimal penalty factor; decomposing the current mixed lightning signal into a linear superposition form of a plurality of decomposed signals by using a VMD algorithm based on the optimal decomposition mode number and the optimal penalty factor; after the decomposition signals representing the noise are removed, linear superposition of the remaining decomposition signals is reconstructed, and the very-low-frequency thunder and lightning signals are obtained. According to the method, the noise signal deeply coupled with the very low frequency lightning signal can be efficiently and accurately removed, and the real very low frequency lightning signal is restored.

The invention discloses a method and a system for establishing a low-frequency model based on multi-attribute fusion. The method for establishing the low-frequency model based on the multi-attribute fusion comprises the following steps: establishing a work area longitudinal wave velocity compaction trend body; based on the longitudinal wave velocity compaction trend body and the seismic horizon velocity body, constructing a pre-stack parameter elastic very low frequency model; establishing a well interpolation model based on the three-dimensional constructive framework; and performing frequency domain merging on the pre-stack parameter elastic very-low-frequency model and the well interpolation model to obtain a multi-attribute fusion low-frequency model. According to the method, seismic velocity information, regional compaction trend information, logging information and geologic model information are fully fused to participate in establishment of the low-frequency model, the'bullseye 'phenomenon of a conventional well interpolation low-frequency model is improved, the overall rule is matched with the structure background, and the problems that well drilling distribution is not uniform, reservoir heterogeneity is high, and the reliability is high are solved. And the low-frequency model precision is not high due to fast transverse change.

The present invention belongs to the field of lightning detection, and specifically relates to an ultra-long-range lightning location method and system based on very low frequency electromagnetic pulse signals, aiming to solve the problem that existing three-dimensional lightning location methods cannot meet the needs of long-range lightning monitoring. The present invention includes: real-time acquisition of lightning electromagnetic pulse data from each detection station and time window screening; secondary matching through signal cross-correlation method; calculation of the initial position of lightning based on the data of secondary matching; iterative optimization through nonlinear least squares algorithm with the initial position of lightning as the center to obtain the lightning position after error optimization; if the distance between the two positions is less than the set error, the optimized lightning position is used as the located lightning position. The present invention can achieve real-time and high-precision detection of lightning activities within a range of thousands of kilometers, with a positioning accuracy of 2-10km within the detection network and positioning accuracy outside the detection network that can be better than 1% of the signal propagation distance. The detection efficiency of lightning within the detection network is higher than 60%, and the maximum detection distance can reach more than 8,000km.

1. Name of the product of this design: Very low frequency message processing graphical user interface for electronic equipment. 2. Purpose of the product of this design: an electronic device. 3. The design highlights of this appearance design product are the graphical user interface content on the screen. 4. The picture or photo that best illustrates the key points of the design: main view. 5.Purpose of the graphical user interface: used to display messages received from wireless networks, high-frequency networks, message terminals, etc. 6. Human-computer interaction mode of graphical user interface: The main view is the main interface of the display screen panel. Users can view "Messages sent to business terminals", "Messages sent by business terminals", "Messages to be uploaded", "Messages uploaded today", "Device status monitoring", "Channel status monitoring" and "Prompt information". In addition, when the user clicks "Shift Change", it will switch to other users to log in to the system. When clicking "System Management", the general message operation submenu will be displayed. When clicking "Exit", the software will be closed and exited.

The present invention discloses a gradient voltage-excited miniature ultra-wideband directional antenna comprising eight arrays and a logarithmic periodic silicon-based support structure. The arrays are directly bonded to the logarithmic periodic silicon-based support structure, forming periodically arranged array pairs. Each array is directly fed by a voltage source, and each array pair generates strong resonance, enhancing the frequency of the corresponding array and increasing the antenna gain. Eight arrays are bonded above the logarithmic periodic silicon-based support structure, with the eight arrays spaced evenly and distributed in a logarithmic pattern. Eight arrays are bonded below the logarithmic periodic silicon-based support structure, with the eight arrays spaced evenly and distributed in a logarithmic pattern, and the eight arrays are aligned above and below. The present invention utilizes gradient voltage excitation, breaking through the inherent relationship between antenna wavelength and antenna size. This achieves miniaturization while providing extremely wideband coverage from very low frequencies to millimeter waves and enhancing antenna gain.

The invention belongs to the field of geophysical exploration, and particularly relates to a very-low-frequency three-component coil calibration method based on frequency sweep excitation, which comprises the following steps: acquiring an alternating-current excitation current and a time domain signal of a three-component coil, and performing frequency domain transformation on the time domain signal to obtain a plurality of frequency domain response vectors covering a frequency sweep range; constructing a linear equation set for describing a coil system error based on a plurality of frequency domain response vectors measured under each attitude and the calculated excitation magnetic field reference vector, and solving the linear equation set by using a least square method to obtain a calibration matrix for correcting measurement data; and the calibration matrix is adopted to correct the measurement data of the three-component coil in the use state, so that systematic errors of the very-low-frequency three-component coil can be accurately calibrated and calibrated, and the measurement precision and data reliability of a very-low-frequency electromagnetic method are effectively improved.

Algorithms for determining optimal low-frequency and sub-perception spinal cord stimulation for a patient are disclosed. A spread bipole is preferably used both to position the stimulation to target a patient's pain, and to provide the resulting therapy. The stimulation is provided at very low frequencies, such as 10 Hz or less, and preferably 2 Hz. Further, sub-perception is provided by the use of lower amplitudes and at longer pulse widths than are conventional in typical SCS stimulation therapies. This results in determined stimulation therapies which draw very little power. Therapy is preferably provided by the use of symmetric biphasic pulses.

The present invention provides a method and system for automatically calibrating the analog front-end gain of a very low frequency detection system. The method comprises: generating a calibration signal sequence based on the total calibration time limit of the analog front-end circuit and the frequency sweep signal period; performing data acquisition on the calibration signal sequence to obtain sampled data; performing signal analysis on the sampled data to obtain the circuit gain of each frequency sweep point, and determining a curve of the gain of each frequency sweep signal varying with frequency; and performing linear interpolation based on the circuit gain of each frequency sweep point to obtain a gain variation curve corresponding to the analog front-end circuit. Through the present invention, the actual circuit gain of the detection system at each frequency point is accurately obtained, thereby significantly improving the accuracy of restoring the true strength of the received signal and solving the problem of insufficient accuracy in the prior art.

The present application belongs to the technical field of very low frequency fluctuation detection, and discloses a very low frequency station signal information extraction method and system based on a phase-locked loop. The present application amplifies and samples a wide frequency signal containing a very low frequency station transmitting signal, sets local MSK demodulation parameters, uses phase-locked loop technology to respectively perform carrier synchronization on the upper and lower frequencies of the MSK modulated signal transmitted by the target monitoring very low frequency station, extracts a baseband synchronization signal and a carrier synchronization signal from the phase-locked loops of the upper and lower frequencies, respectively, calculates the amplitude information of the upper and lower frequencies using the baseband synchronization signal, and further obtains the amplitude information of the target monitoring very low frequency station. The carrier synchronization signals of the upper and lower frequencies are used to extract the frequency of the carrier synchronization signal of the MSK modulated signal transmitted by the target monitoring very low frequency station, and further extract the phase offset information of the target monitoring very low frequency station. The present application can improve the accuracy of very low frequency station signal information extraction.

The invention relates to the technical field of ocean exploration and underwater acoustic communication, in particular to a mechanical very-low-frequency sound source transmitting device and transducer, which comprises a multidirectional transmission structure (1), a radiant panel (2), a main shell (4), a motor (5) and a speed reducer (6), the main shell (4) is of a hollow symmetrical structure and is provided with a top end face, a bottom end face and a plurality of side end faces. The plurality of side end surfaces are encircled to form a regular polygon; the side end surface is provided with a radiation plate (2) as a radiation surface; the inner end face of the radiant panel (2) is in contact with the internal environment of the main shell (4), and the outer end face is in contact with the external environment of the main shell (4); the multidirectional transmission structure (1) is arranged in the main shell (4) and is in contact with the radiant panel (2); rotation of the motor (5) is decelerated through the speed reducer (6) and then drives the multidirectional transmission structure (1), and the multidirectional transmission structure (1) converts rotation motion of the motor (5) into horizontal vibration of the radiant panel (2) so as to achieve underwater very-low-frequency sound source emission.

The invention discloses a mainland slope sea area underwater very low frequency line spectrum target positioning method. According to the method, firstly, a three-dimensional sound field model based on space coordinate rotation transformation is constructed, the problem that the array element position of a horizontal receiving array cannot accurately fall on a computational grid point is solved, and meanwhile, rapid forecasting is achieved on an array element receiving signal of the horizontal receiving array. And then estimating the multi-path direction of arrival of each modal by adopting an MVDR algorithm, and realizing accurate positioning of the underwater sound source position through horizontal sound ray anti-tracking in combination with a vertical modal-horizontal ray theory. And finally, the average modal phase velocity is introduced to improve the precision of multi-path direction of arrival estimation, the multi-path direction of arrival of each order of modal is estimated more accurately, and the positioning error of the underwater sound source position is further reduced.

The present invention discloses a method for measuring the shear wave velocity of the shallow seafloor sediment layer based on a single vector hydrophone. The measurement method includes: collecting underwater acoustic signals and seafloor interface wave signals excited by a very low frequency sound source near the seafloor using a single vector hydrophone; obtaining the horizontal component of the particle velocity by rotating the quasi-source direction using the horizontal transverse component and the horizontal longitudinal component of the particle velocity; calculating the amplitude ratios between the sound pressure, the vertical component of the particle velocity, and the horizontal component of the particle velocity pairwise, and calculating the interface wave velocity using any one of the amplitude ratios; and finally calculating the shear wave velocity according to the linear relationship between the interface wave and the shear wave. The method of the present invention can accurately estimate the shear wave velocity of the shallow seafloor sediment layer, and the detection device only requires a single vector hydrophone, providing a feasible technical approach for solving long-term problems such as difficult seafloor shear wave measurement, high cost, and low efficiency.

The application discloses a dynamic non-cooperative very low frequency signal carrier frequency and phase measurement system, comprising a high-precision analog-to-digital converter, a high-precision digital-to-analog converter connected with an FPGA module, and a labview host computer connected with the FPGA module, and discloses a dynamic non-cooperative very low frequency signal carrier frequency and phase measurement method. The FPGA module is used for performing carrier frequency estimation and carrier phase rotation correction on MSK signals collected by the high-precision digital-to-analog converter, and the carrier frequency and phase with high precision are transmitted to the labview host computer to be displayed. The application can realize fast and high-precision carrier frequency estimation, has strong noise resistance and a wide estimation range.

The embodiment of the invention provides a very low frequency signal monitoring method and device, and the device consists of a signal receiving unit (1), a signal measurement unit (2), a parameter regulation and control unit (3), and a main control unit (4). And the parameter regulation and control unit (3) can respectively set parameters of each working component in the signal receiving unit (1) and the signal measuring unit (2) according to the center frequency and bandwidth list of the main control unit (4), and can control a turntable (5) of an antenna coil (13) to align to the strongest direction of a synchronous measurement signal, so that measurement and data storage of a specific very low frequency signal in the bandwidth are realized. The method is characterized in that collection of monitoring signals and measurement of signal parameters are realized based on synchronization characteristics of known signals, interference signals can be well distinguished, and the accuracy of monitoring data is guaranteed.

The invention provides an ionosphere parameter inversion method and device, and belongs to the technical field of short-wave communication, and the method comprises the steps: enabling the actually-measured amplitude and phase difference to be mapped into a low-order wave mode excitation amplitude and a complex feature value through the synchronous receiving of the same very-low-frequency transmitting station signal at different transmitting and receiving distances on the ground; and then fast convergence solution is carried out by using a Newton-Raphson method, and ionosphere electron concentration parameters are circularly corrected by using a gradient descent method, so that the residual error of a theoretical calculation result and a measured value is stabilized within a preset threshold, thereby getting rid of excessive dependence on a traditional ionosphere mode, remarkably improving the inversion precision of low ionosphere parameters, and improving the reliability of the low ionosphere. The method has the advantages of simple operation, low cost and long-term operation.

The present invention proposes a shallow seabed geoacoustic parameter inversion method, system, equipment and medium based on very low frequency water-ground modal interference. The present invention considers very low frequency sound propagation in a layered shallow sea environment, and part of the energy is coupled into the seabed to capture the geoacoustic mode propagation of the sediment layer. The water acoustic mode group velocity is negatively dispersed and the geoacoustic mode is positively dispersed. Therefore, the interference structure of the two is no longer in the form of stripes, but changes nonlinearly with frequency. This special interference structure is related to the modal propagation and dispersion characteristics in the sediment layer, and the dispersion characteristics are related to the acoustic parameters of the water body and the seabed. It is a new method for inverting environmental parameters with better inversion effect.

The application provides a piezoelectric driving self-biased very low frequency mechanical transmitting antenna and a preparation method thereof. The preparation method comprises the following steps: step one, preparing piezoelectric ceramic material; step two, cutting and slotting; step three, pouring resin; step four, cutting layer sheet; step five, packaging; step six, polarization treatment; step seven, preparing adhesive layer; and step eight, hot-pressing compounding. Compared with the existing magnetoelectric antenna, the self-biased very low frequency mechanical transmitting antenna has the characteristics of self-bias, high piezoelectricity, miniaturization, no additional noise source and electromagnetic interference, and the like, has the advantages of high stress transmission efficiency and small ohmic loss, can realize the miniaturization requirement of the magnetoelectric mechanical antenna, is easy to form a large-scale array, improves the magnetic transmitting performance under zero bias, and achieves the low frequency communication effect.

The invention discloses a very-low-frequency narrow-band antenna pre-distortion broadband transmitting method. The core of the very-low-frequency narrow-band antenna pre-distortion broadband transmitting method is composed of double-tuning network parameter calculation and pre-distortion waveform design. The method comprises the following steps: with a constraint condition that transmitter port equivalent impedance is equal to transmitter characteristic impedance under an antenna center frequency, adjusting a load current gain peak frequency to a working frequency by calculating an undetermined parameter so as to realize working frequency point tuning; changing parameters of the double-tuned network to design a low-Q-value target group, acquiring primary and secondary side currents under constant-amplitude excitation, importing the primary and secondary side currents into an actual network of an experimental group, and deducing corresponding excitation voltage; according to the method, tuning and resistance changing are achieved through the double-tuning network, transient current fluctuation suppression is achieved through the pre-distortion design, and the active power utilization rate and the very-low-frequency communication rate of the power amplifier are effectively improved.

The present invention belongs to the field of electromagnetic wave technology, and discloses a very low frequency scattering method of anisotropic ionosphere in medium and low altitude based on the transmission matrix method. The present invention establishes a low ionosphere layered model structure considering the anisotropy of the ionosphere. First, the transmission matrix of the anisotropic layered structure is derived and verified. Then, based on the transmission matrix, the scattering characteristics of the very low frequency electromagnetic waves in the above-mentioned ionosphere layered structure under different conditions are accurately calculated, and the propagation law is summarized. This work provides a reliable calculation model for the propagation of very low frequency in the low and medium ionosphere, and greatly improves the accuracy of its propagation and scattering parameter calculation. This has important guiding and reference value for studying the propagation of very low frequency electromagnetic waves in the atmosphere.

This invention discloses a lightweight monopole transmitting antenna for an aerostat. From the inside out, it comprises a central reinforcing filler made of multi-strand twisted lightweight reinforcing fibers, a binding layer made of polytetrafluoroethylene film, a non-metallic reinforcing layer woven from non-metallic reinforcing fibers, an inner sheath made of extruded polyethylene, a radiator layer woven from metal wires, and an outer sheath comprising a semi-conductive outer sheath and a metal-woven outer sheath. The semi-conductive and metal-woven outer sheaths have the same outer diameter and alternately cover the outside of the radiator layer. This invention offers advantages such as miniaturization, lightweight, corona resistance, high current resistance, and fatigue resistance, resulting in high reliability and practicality, meeting the requirements for rapid deployment of long-range very low frequency (VLF) communication systems using aerostats.

The application belongs to the technical field of preparation and determination of aviation equipment absorbing material, and discloses a wide low-frequency sound absorption and vibration reduction covering layer structure and a design method. The design method comprises the following steps: by changing the geometric parameters of a single unit composed of an embedded neck hole diameter d, an embedded neck length l and a cavity wall plate height L, the strong non-local coupling between a plurality of embedded rubber Helmholtz resonators is changed, the impedance of the embedded rubber Helmholtz resonator is changed, and the overall structure of the wide low-frequency sound absorption and vibration reduction covering layer structure of the sound absorption metasurface array is obtained by the weak coupling resonance sound absorption mechanism; the embedded rubber Helmholtz resonator is composed of an embedded neck, a damping rubber coating layer and a sound absorption cavity. The non-local coupling between the plurality of embedded rubber Helmholtz resonators in the multi-element metasurface array is adjusted, effective broadband impedance modulation is realized, and strong dissipation of broadband sound energy is realized at very low frequency.

The application provides a very low frequency atomic magnetometer environment interference suppression method based on polarization selection reception, wherein a precession main magnetic field B e and -B e are respectively applied by a main magnetic field coil in z direction and -z direction in front and back two regions of a gas chamber e and -B e regions are detected by using detection laser in x direction; external very low frequency signals are detected by interaction with atoms polarized in z direction to make the atoms produce precession signals in xOy plane, so that the signals are detected by light detection; when the external signals are linear polarization, according to the selection rule of angular momentum conservation, the precession signals of atoms in B e and -B e regions are offset, so that the system does not respond to linear polarization signals; for circular polarization signals, only atoms in B e or -B e region have precession signals, so that the detection of circular polarization signals is realized. The technical scheme of the application is applied to solve the technical problem of environmental magnetic noise interference of a very low frequency atomic magnetometer in an actual application scene in the prior art.