39 results about "Spectral function" patented technology

The invention provides a planetary gearbox intelligent fault diagnosis method based on ITD and LSTM-CNN, and relates to the technical field of planetary gearbox fault diagnosis. The planetary gear box intelligent fault diagnosis method based on the I TD and the LSTM-CNN comprises the following steps that firstly, vibration signals of a planetary gear box are collected through a sensor, I TD decomposition is carried out on each sampling signal to obtain a plurality of PR components, the PR components with large instantaneous frequency fluctuation are selected through Hilbert transform, and the PR components with large instantaneous frequency fluctuation are obtained; converting the reconstructed signal into a frequency spectrum function through Fourier transform, extracting the amplitude of a feature frequency, constructing a feature vector, inputting the feature vector into an LSTM-CNN for intelligent diagnosis, and combining a classification cross entropy loss function to ensure the stability of calculation and the high efficiency of training. A comprehensive and efficient solution is provided for fault type and degree diagnosis of the sun gear of the gear transmission system, and compared with a classic neural network model, the diagnosis accuracy of different types of gear faults and different degrees of faults is improved.

The invention discloses a low-redundancy high-order direction finding method and system based on co-prime characteristics and a computer storage medium, and the method comprises the steps: receiving signals from a plurality of signal sources through employing a low-redundancy array obtained through improvement based on a co-prime array, and obtaining a received signal; calculating a fourth-order cumulant matrix of the received signal according to the received signal; obtaining a covariance matrix according to the fourth-order cumulant matrix; according to the covariance matrix, calculating to obtain a characteristic value and a characteristic vector of the covariance matrix; dividing the feature vector into a signal subspace and a noise subspace according to the size of the feature value; constructing a spectral function according to the projection of the steering vector on the noise subspace; and searching peak values of the spectral function in all possible directions, and determining the direction of the signal source. According to the low-redundancy array obtained based on improvement of the co-prime array, on the basis that the number of receiving array elements is reduced, the number of estimated signal sources is increased, the fourth-order cumulant is adopted, and the positioning precision in a non-Gaussian noise environment can be improved.

The invention discloses a chirp grating design method and device, equipment and a storage medium, and relates to the technical field of optical fibers, and the disclosed chirp grating design method comprises the steps: analyzing a preset target spectrum function to obtain a target grating structure parameter; layering the initial grating into a plurality of sub-grating regions with uniform periods based on the target grating structure parameters, and establishing a layered transmission matrix model; determining a refractive index modulation depth range of each sub-gate region according to the layered transmission matrix model; and performing iterative optimization on grating structure parameters of the initial grating according to the layered transmission matrix model, the target spectral function, the refractive index modulation depth range and a preset error function to obtain a target grating. The performance of the chirp grating can be optimized.

The invention discloses a forward modeling simulation method for a multidirectional sea wave induction electromagnetic field. The method comprises the following steps: expressing energy distribution of different propagation directions and frequency components through a spectral function; setting external environment input required by forward modeling according to the seawater depth and geomagnetic field parameters of the research area; after parameter setting is completed, electromagnetic response calculation is carried out on each frequency-direction sampling point; component response is called on a preset frequency set and a preset direction set, linear superposition is carried out by adopting a frequency direction correspondence method, and a total electromagnetic field is obtained; and outputting time sequences and frequency spectrum results of the wind wave induction electromagnetic field, the surge induction electromagnetic field and the mixed wave induction electromagnetic field, thereby providing a reference basis for noise analysis, background interference suppression and target signal identification in electromagnetic detection. According to the method, the limitation of a traditional model is broken through, the electromagnetic interference characteristics under the complex sea condition are represented more truly, and reliable support is provided for noise suppression and target recognition in electromagnetic detection.

The invention provides a passive positioning method based on a wireless fidelity (Wi-Fi) beam forming feedback information (BFI). The passive positioning method comprises the following steps of: firstly, carrying out passive positioning on the basis of the Wi-Fi beam forming feedback information (BFI); the method comprises the following steps: firstly, pre-determining the position of a transceiver, and respectively extracting BFIs of a direct path and a target reflection path of the transceiver; compared with extraction of channel state information (CSI), the BFI is inherent information in a Wi-Fi communication protocol, special acquisition hardware does not need to be additionally deployed, the BFI can be directly extracted from the communication process, the hardware cost and the deployment threshold of a positioning system are greatly reduced, and large-scale popularization and application are easier to realize. And secondly, by constructing a BFI covariance matrix, high-dimensional matrix operation in a traditional MUSIC algorithm is converted into low-dimensional matrix processing, and the calculation complexity is remarkably reduced. And finally, constructing a spectral function to respectively obtain an angle of departure (AOD) of a direct path of the transceiver and a target reflection path and a flight time difference of the two paths, substituting the parameters into the elliptic constraint model for calculation, and finally solving to obtain an estimated position of the target. According to the method designed by the invention, the real-time performance and the deployment flexibility of the system are greatly improved under the condition that the calculation complexity is remarkably reduced and the support of specific hardware is not needed.

The application discloses a non-rigid point cloud registration method and a storage medium, and the non-rigid point cloud registration method comprises the following steps: establishing a first neural network for generating a high-dimensional feature embedding matrix, and training the first neural network according to a first target, wherein the first target is to make the Euclidean distance between each two high-dimensional feature embeddings in the generated high-dimensional feature embedding matrix equal to the geodesic distance of the corresponding two points in the input point cloud; establishing a second neural network for generating a high-dimensional feature descriptor matrix, and training the second neural network based on the high-dimensional feature embedding matrix; inputting two point clouds to be registered into the trained first neural network and second neural network to obtain two high-dimensional feature embedding matrices and two high-dimensional feature descriptor matrices; further calculating a spectral function mapping, and then calculating a corresponding relationship mapping of the two point clouds to be registered. The application not only improves the calculation efficiency, but also has robustness in processing noise and various incompleteness.

The present application relates to a method, device and storage medium for contour following control of a harvesting machine header. The method includes the steps of: obtaining geographical information of a target plot; generating a ground spectral function of the target plot according to the geographical information; obtaining initial motion data of the harvesting machine; generating virtual operation parameters of the harvesting machine according to the initial motion data; obtaining real-time motion data of the harvesting machine; and adjusting the real-time motion data in real time according to the virtual operation parameters. The method, device and storage medium for contour following control of a harvesting machine header provided by the embodiments of the present application can adjust control parameters according to the traveling speed of the harvesting machine to ensure that the header will not respond too slowly during high-speed movement or overshoot too much during low-speed movement.

The application discloses a low-redundancy high-order measurement direction method and system based on the coprime characteristic and a computer storage medium, and the method comprises the following steps: receiving signals from multiple signal sources by using a low-redundancy array improved based on a coprime array to obtain received signals; calculating a fourth-order cumulant matrix of the received signals according to the received signals; obtaining a covariance matrix according to the fourth-order cumulant matrix; calculating eigenvalues and eigenvectors of the covariance matrix according to the covariance matrix; dividing the eigenvectors into a signal subspace and a noise subspace according to the sizes of the eigenvalues; constructing a spectral function according to projections of the steering vectors on the noise subspace; searching for peak values of the spectral function in all possible directions to determine the directions of the signal sources. The low-redundancy array improved based on the coprime array can not only expand the estimated number of signal sources on the basis of reducing the number of received array elements, but also adopt the fourth-order cumulant, so that the positioning precision in a non-Gaussian noise environment can be improved.

The purpose of this invention is to provide a method for DOA estimation of acoustic vector arrays based on quaternion matrix dimensionality reduction, comprising the following steps: constructing a CAACIS acoustic vector coprime array at the receiver; establishing a quaternion model of the received signal based on the array output; estimating the quaternion covariance matrix; performing dimensionality reduction on the quaternion covariance matrix to obtain a virtual array received signal model of the acoustic vector coprime array; reconstructing the Hermitian-Toeplitz matrix; performing eigenvalue decomposition on the Hermitian-Toeplitz matrix and constructing a spatial spectral function; and obtaining the DOA estimation result through spectral peak search. This invention addresses the problem of how to achieve multi-objective DOA estimation with both low complexity and good performance based on a quaternion framework under acoustic vector coprime arrays.

The application discloses a method for calculating lattice thermal conductivity of rare earth oxide based on first principle. The method comprises the following steps: establishing a crystal structure model of the rare earth oxide, and constructing a supercell model after structure optimization; calculating second-order interatomic force constants by using a first principle method to obtain a phonon dispersion relation, and calculating third-order interatomic force constants to obtain a phonon scattering rate; solving the lattice thermal conductivity by using a Wigner transport equation, wherein the lattice thermal conductivity comprises a particle contribution described by a diagonal item of a phonon spectral function and a wave contribution described by a non-diagonal item, and the two are added to obtain a thermal conductivity contribution of each phonon mode; and integrating and summing all phonon modes in a Brillouin zone to output a frequency, temperature and direction dependence of the total lattice thermal conductivity. The application can accurately predict the lattice thermal conductivity and anisotropy of the rare earth oxide in a wide temperature range without an empirical parameter.

A method and apparatus for super-resolution localization of multiple targets using frequency-modulated continuous wave radar includes: determining the number K of targets based on the number of eigenvalues ​​satisfying a condition in the covariance matrix of the acquired radar array signal; finding the frequency values ​​corresponding to the K largest spectral peaks based on the acquired number of targets K, using these frequency values ​​as coarsely estimated intermediate frequency (IF) values, and determining the final IF value using the coarsely estimated IF values; calculating the distance of the corresponding target relative to the center O of the antenna array based on the final IF value; obtaining the noise subspace of the array signal and the steering vector related to the target distance and angle based on the eigenvalues ​​of the covariance matrix of the array signal, constructing a MUSIC spectral function, and determining the estimated value of the target echo signal direction; and then determining the position of the corresponding target. This invention has higher range and angle resolution and lower algorithm complexity, enabling super-resolution localization of multiple targets.

The invention relates to a method of Raman spectroscopy. The method comprises the following steps: determining a measurement spectrum by using a Raman spectrometer; determining a second derivative of the difference spectral function corresponding to a difference between the measured spectrum and a product of the scaling coefficient and a reference spectrum of contributions of interference effects contained in the measured spectrum; determining a coefficient value that minimizes a scaling coefficient of an error function, the error function comprising a term corresponding to an error of the difference spectral function due to peaks contained in the reference spectrum, the term comprising a sum of areas surrounded under the second derivative in all spectral regions in which the second derivative is positive, and / or wherein the second derivative is the sum of the areas surrounded below the second derivative in all spectral regions with negative; and determining a Raman difference spectrum corresponding to a difference between the measured spectrum and a product of the coefficient value and the reference spectrum.

This invention discloses a direction-of-arrival (DOA) estimation method based on a reorganized nested array configuration. The method comprises the following steps: reordering two subarrays of a nested array to construct a reorganized nested array configuration; calculating the differential co-array and its maximum continuous degree of freedom of the reorganized nested array; spatially sampling the target radiator based on the reorganized nested array and vectorizing the covariance matrix of the antenna array's received signal; reconstructing the incident signal components based on a compressed sensing method; and constructing a spectral function and performing a spectral peak search to estimate the DOA of the target radiator. The invention proposes a differential co-array with a hole-free characteristic in the reorganized nested array configuration, which expands the array's degrees of freedom and effective array aperture, enabling high-precision underdetermined DOA estimation.

The invention belongs to the field of digital signal time-frequency analysis, and provides a frequency super-resolution time-frequency analysis method based on eigenvalue decomposition, which comprises the steps of intercepting a signal sequence along a time axis, constructing a virtual matrix, carrying out eigendecomposition on a covariance matrix, constructing a noise matrix, calculating pseudo-spectrum functions and combining the pseudo-spectrum functions along the time axis to form a time-frequency graph. The method does not depend on the number of time domain sampling points, geometric structure information of signals is extracted through subspace decomposition insensitive to noise, limitation of an STFT time window is broken through, high-frequency resolution can still be achieved under the condition of a short window, the time-frequency contradiction problem of STFT is relieved, and the method has the advantages of being simple in structure and convenient to operate. And a new technical approach is provided for accurate detection and parameter extraction of non-cooperative signals in an optical down-conversion electric field measurement system.

The invention discloses a wave direction angle analysis method and equipment, and belongs to the field of wave test simulation. The method comprises the following steps: 1) generating a target area wave height data array; 2) performing forward and backward smoothing on the wave height data array of the target area to obtain a doubled data array; 3) calculating a covariance matrix of the doubled data array; 4) calculating an optimized covariance matrix by using a spatial smoothing method; 5) calculating all eigenvalues and eigenvectors of the optimized covariance matrix; 6) arranging according to the sizes of the characteristic values, distinguishing signal subspaces / noise subspaces, and constructing a noise matrix; 7) performing translation and reciprocal weighting processing on the characteristic value of the noise subspace to obtain a weighted noise matrix; 8) constructing a spectral function by using an orthogonal relationship between the wave steering vector and the weighted noise matrix, and 9) calculating the spectral function corresponding to all angles, wherein the angle corresponding to the peak value of the spectral function is the oblique wave direction estimation angle.The method can quickly and accurately calculate the wave field direction angle in real time.

The invention provides a method, a device and equipment for rapidly extracting a moire fringe alignment deviation based on a graphics processor, and the method comprises the steps: receiving two groups of moire fringe signals which are obtained by analyzing two groups of moire fringe patterns representing an alignment state; performing parallel collaborative fast Fourier transform on the two groups of moire fringe signals by using a graphics processor to respectively obtain frequency domain representations corresponding to the two groups of moire fringe signals; calculating to obtain a frequency spectrum function representing the phase deviation of the two groups of moire fringe signals based on the two groups of frequency domain representations by using a graphics processor; wherein the frequency spectrum function is used for determining the phase deviation between the two groups of moire fringe signals, and the phase deviation is used for representing the alignment deviation.

The invention discloses an unmanned aerial vehicle monitoring method based on an extended Kalman filter and a MUSIC algorithm, and the method comprises the steps: a data center processes an echo signal through the MUSIC algorithm, obtains a spectral function, uniformly takes a plurality of angle values in a search window, and substitutes the angle values into a spectral function curve, and the angle value spacing is a step length; finding out a candidate peak in the spectral function curve and matching the candidate peak with the unmanned aerial vehicle, wherein a direction angle of the candidate peak is a measurement azimuth angle of the matched unmanned aerial vehicle; and then, based on the EKF in combination with the measured azimuth angle, obtaining the state vector of the unmanned aerial vehicle, and fitting the flight path of the unmanned aerial vehicle according to the state vectors at multiple moments. The search window and the step length at each moment can be adjusted for spectral function curve fitting at the next moment. According to the search window and the step length dynamically adjusted according to the target state, the accuracy of the result is improved on the premise of controlling the calculation amount; according to the method, a plurality of maximum values in the curve can be processed, and track aliasing is effectively avoided; a result is obtained through EKF, noise influence is reduced, and authenticity is guaranteed.

The invention provides a sleep and emotion regulation control method and system based on a specific spectrum function, and belongs to the technical field of medical equipment.The method specifically comprises the steps that a user is regulated and controlled according to regulation and control user data and in combination with the consistent degree of sleep feature signals of the user in the light sleep stage, and the sleep state of the user is adjusted and controlled; the method comprises the following steps: determining a stopping control method for sleep and emotion regulation and control processing with a specific spectrum function, carrying out stopping control processing on a regulation and control user based on the stopping control method, and according to stopping control data of the regulation and control user, when determining that personalized sleep staging model construction processing needs to be carried out, according to the stopping control data of the regulation and control user, establishing a personalized sleep staging model according to the stopping control data of the regulation and control user. According to the method, the pause matching condition of the regulation and control user is determined, the construction processing target of the personalized sleep staging model is determined based on the pause matching condition and the stability condition of the sleep feature signal, and the reliability degree in the sleep and emotion regulation and control process based on the specific spectrum function is improved.

The application provides a sleep and emotion regulation control method and system based on specific spectral function, and belongs to the technical field of medical devices, and specifically comprises the following steps: according to the regulation and control user data, and in combination with the consistency degree of the sleep characteristic signal of the regulation and control user in the light sleep stage, the regulation and control user is regulated and controlled, the determination of the suspension control method of the sleep and emotion regulation processing of the specific spectral function is adopted, the suspension control processing of the regulation and control user is carried out based on the suspension control method, according to the suspension control data of the regulation and control user, when it is determined that the construction processing of the personalized sleep staging model needs to be carried out, according to the suspension control data of the regulation and control user, the suspension matching condition of the regulation and control user is determined, based on the suspension matching condition and the stability condition of the sleep characteristic signal, the determination of the construction processing target of the personalized sleep staging model is carried out, and the reliability in the sleep and emotion regulation control process based on the specific spectral function is improved.

The invention discloses a near-field coherent signal source positioning method and system based on overlapped sub-arrays and iterative optimization, and belongs to the technical field of signal processing, and the method comprises the steps: dividing the whole array antenna into two arrays, and decomposing a received signal into two receiving sub-arrays; for each receiving sub-array, forming a new covariance matrix by an outer product of back diagonal elements corresponding to the covariance matrix of the receiving sub-array; carrying out eigenvalue decomposition on the new covariance matrix of each array, and constructing an angle polynomial equation based on a spectral function to obtain an angle estimation value corresponding to the center of the array; obtaining respective corresponding target distances by using the angle estimation values of the two array centers, and obtaining an initial angle and a distance estimation value of a signal source relative to the whole array antenna; and optimizing the initial angle and distance estimated values by adopting an alternating oblique projection method to obtain the optimized angle and distance of the signal source. The method has better robustness in a coherent signal environment, and is suitable for high-precision near-field positioning.

This invention relates to the field of underwater acoustic signal processing technology, and in particular to a method for enhancing the line spectrum of moving targets based on an elite selection genetic algorithm. Based on the Doppler-warping transform, the method utilizes an elite selection genetic algorithm to autonomously optimize and estimate the target's motion parameters. Using the entropy of the transformed target signal's spectral function as the cost function, the optimal motion parameters are searched by comparing the spectral entropy values ​​under different parameters. Then, the optimal parameters are used to perform a Doppler-warping transform on the original signal, refocusing the line spectrum energy dispersed by the Doppler effect near the original frequency, thus achieving autonomous enhancement of the moving target's line spectrum. This invention effectively solves the problems of the inability to accumulate moving target line spectrum energy over long periods and the autonomous search of Doppler-warping transform parameters, improving the probability and accuracy of line spectrum detection. It can be applied to data backtracking and review processing in underwater moving target detection, and has good engineering practical value.

The invention discloses a robust hydrophone array orientation estimation method. According to the scheme, amplitude-phase error correction is introduced, and phase error vector and energy normalization are utilized to realize amplitude-phase error correction. The method comprises the following steps: correcting data, reconstructing a covariance matrix by using the corrected data, calculating a spatial spectrum by using the reconstructed covariance matrix, then calculating a first-order difference function of a spectral function, and performing spectral peak search on a differentiated spatial spectrum curve to estimate the direction of an incident signal. Simulation experiment and lake test experiment results show that the method greatly reduces the influence of amplitude-phase errors on DOA estimation performance, improves the orientation estimation precision, and is low in calculation complexity. The scheme of the patent has important application value in ocean instruments such as subsurface buoys and ocean mobile observation platforms, and has high practical engineering application value.

The application discloses a spectrometer based on light waveguide leakage mode light splitting and a spectrum reconstruction method thereof. The spectrometer comprises an image sensor and at least one light waveguide, the surface of the image sensor is coated with a substrate layer, the first end of the light waveguide is connected with a light source as an entrance, and the second end of the light waveguide is adsorbed on the surface of the substrate layer after being heated and drawn. The spectrum reconstruction method comprises the following steps: calibration: the photocurrent value of the sensor unit at each wavelength is saved as a spectral response function; collecting photocurrent: collecting the photocurrent value of the to-be-detected light in any sensor unit; constructing an equation set and solving: obtaining k actual spectral functions of the to-be-detected light, solving the corresponding photocurrent equation and composing a linear equation set, and solving to obtain the reconstructed actual spectral function of the to-be-detected light. The application has the advantages of small physical volume, multi-channel detection and accurate detection result.

The invention relates to a portable in-situ self-scanning multispectral microscopic spectrum system. The system comprises a multispectral microscopic spectrum measurement module, a movable self-supporting structure, a microscopic objective lens assembly and an objective lens scanning mechanism which are integrated; wherein the multispectral microscopic spectrum measurement module is used for realizing excitation and signal acquisition of multiple spectrum modes, and the spectrum modes comprise but are not limited to fluorescence spectrum, Raman spectrum and white light absorption spectrum; the microscope objective assembly is used as a unified in-situ optical interface, so that measurement of different spectrum functions is completed in the same light path and the same space coordinate system; the objective lens scanning mechanism is used for driving the microscope objective lens assembly to perform scanning movement in at least two space directions, so that multispectral space scanning measurement is realized under the condition that a measured object is kept relatively static, and state disturbance and measurement errors caused by moving a sample through an objective table traditionally are avoided; and the movable self-supporting structure is used for quickly deploying and keeping the system stable in different use scenes.

This invention proposes a fusion subspace DOA estimation method based on sparse Bayesian learning. The implementation steps are as follows: first, an overcomplete steering vector dictionary matrix is ​​constructed, and a sparse representation model is built. Then, the signal is reconstructed using the sparse Bayesian learning algorithm. After obtaining the reconstructed signal, a signal covariance matrix is ​​constructed. Finally, eigenvalue decomposition is performed on the covariance matrix to construct a spatial spectral function, and the peak value of this spectral function is searched across the entire angular range. This invention integrates the SBL algorithm and the MUSIC algorithm. The MUSIC algorithm is used to perform subspace decomposition on the reconstructed covariance matrix, extracting the noise subspace and utilizing its orthogonality with the steering vector, thereby improving the angular resolution of the SBL algorithm. This makes this invention applicable to achieving high-resolution DOA estimation under conditions of few or even single snapshots.

The invention relates to a monopole cross loop antenna signal direction finding method combining amplitude comparison and variable step size MUSIC, and the method mainly comprises the steps: obtaining an initial estimation angle through an amplitude comparison algorithm, if the angle is located in a loop antenna cross angle domain, directly taking the angle as a final result through the high-precision characteristic of the amplitude comparison algorithm in the angle domain, and carrying out the direction finding of the monopole cross loop antenna signal. The direction finding performance of the angular domain is improved; and if the spatial spectrum function is not located in the cross angle domain, the spectral peak search range of the MUSIC algorithm is further narrowed by using the initial estimation result, and the spatial spectrum function is searched by adopting a variable step size mode, so that the direction finding resolution of the MUSIC algorithm is improved, and the calculation complexity is reduced at the same time. According to the method, two direction finding algorithms of amplitude comparison and MUSIC are utilized, high-precision direction finding in a loop antenna cross angle domain is realized, a higher resolution success rate is shown, the direction finding efficiency is effectively improved, and the method has important application value in the fields of high-frequency radar ocean current detection, short-wave communication and the like.

The invention provides a broadband micro-pulse differential absorption laser radar, which comprises a transmitter, a receiver and a telescope primary mirror, and is characterized in that the transmitter comprises an on-line transmitting unit, an off-line transmitting unit, a first collimating lens, a second collimating lens, a first 1 / 2 wave plate, a second 1 / 2 wave plate, a polarization beam combiner, a first 1 / 4 wave plate and a first negative lens; the receiver comprises an on-line detection unit, an off-line detection unit, a 45-degree total reflection mirror with a center hole, a second negative lens, a second 1 / 4 wave plate, a polarization beam splitter, a first optical filter, a second optical filter, a first convergent lens and a second convergent lens. And constructing an objective function by the broadband emission beam spectral function, the water vapor absorption cross section spectral function and the normalized receiving signal, and estimating water vapor molecular density elevation distribution which minimizes the objective function value to form a water vapor vertical profile. The laser radar is low in power consumption, simple and reliable in structure, safe in human eyes and unattended, and can become a node sensor of a new generation of national and foundation meteorological observation networks.

Provided are a filling level monitoring device for a fluid gas container, a hydrogen tank, and an aircraft including such a hydrogen tank. **Solution**: A filling level monitoring device (100) for monitoring a filling level (210) of a fluid in a container (200) includes an exciter (10), a sensor (20), a signal source (30) connected to the exciter (10), a processor (40), at least one spatial orientation and acceleration sensor (60), and a filling level indicator (50). The device (100) uses the signal source (30) and the exciter (10) to couple a vibration load having a number of frequency components to the container (200). The sensor (20) measures vibrations in the container (200) after the exciter (10) transmits the vibration load to the container (200). The processor (40) performs a spectral analysis of an input signal (31) and a vibration signal (21) from the sensor (20), compares each of these spectral functions, and extracts a resonance frequency of the container (200) based on the spatial orientation of the container (200). The filling level indicator (50) calculates a current filling level (210) of the container (200) from the extracted resonance frequency and a spatial orientation signal from the spatial orientation sensor (60) by correlating the collected data with reference data.

The invention provides a passive positioning method for an MIMO-OTFS system. The method comprises the following steps: establishing communication connection between a transmitting end and a receiving end through a protocol; a transmitting end is used for transmitting signals, and a receiving end receives the signals through a channel tool to obtain original channel state information; performing CP decomposition operation on the original channel state information; performing signal subspace division and noise subspace division on the decomposed tensor in sequence to construct a mapping matrix, designing a spectral function by using the mapping matrix, and performing multipath parameter estimation through spectral peak search operation; and estimating motion attribute information of the target based on the accurately estimated channel parameters in combination with priori information of a perception environment to obtain position estimation and a motion track of the target. The method can effectively deal with a complex multi-path indoor environment, realizes a more accurate position estimation result by using an existing commercial terminal without a large-aperture array, and can greatly improve the robustness of a positioning system.

The present application discloses a noise reduction method and device for laser absorption spectroscopy. The method includes: determining a laser absorption spectrum formed when a laser irradiates a gas to be measured; determining a noise reduction spectrum under current environmental variables according to a noise reduction spectral function corresponding to the current pressure of the gas chamber where the gas to be measured is located and the relationship between the current temperature and the laser absorption spectrum, the noise reduction spectrum and the laser absorption spectrum being in the same coordinate system, and the current environmental variables including the current temperature and the current pressure; determining an update direction and an update displacement amount of the noise reduction spectrum in the coordinate system by comparing the laser absorption spectrum and the noise reduction spectrum; updating the position of the noise reduction spectrum in the coordinate system according to the update direction and the update displacement amount until the updated noise reduction spectrum meets a preset condition, and the noise reduction spectrum that meets the preset condition is the laser absorption spectrum after noise filtering. The present application can reduce the influence of various noises on the laser absorption spectrum of the gas to be measured, and thus is beneficial to improving the detection accuracy.