28 results about "Spherical wave" patented technology

This application discloses a method, apparatus, device, and medium for self-calibration of an ultrasonic sensor for transformers. The method involves obtaining the spatial distance by using the time difference and measured sound velocity of the same partial discharge pulse received by a built-in UHF antenna and an external ultrasonic sensor; constructing a cross-medium model based on the acoustic parameters of the insulating oil and the tank to calculate the sound pressure transmission coefficient at the liquid-solid interface; constructing a spherical wave dissipation equation in viscous oil by combining discharge and fluid parameters, and calculating the theoretical sound pressure of the outer shell using the distance and transmission coefficient; comparing the measured peak output voltage of the external sensor with the in-situ acoustic-electric conversion sensitivity for online self-calibration. This method reconstructs a high-fidelity sound wave propagation attenuation model, which can improve calibration accuracy and diagnostic reliability.

The application discloses a crimped cylindrical wave tight field device, which mainly comprises a crimped parabolic cylindrical reflector, a feed source, a quiet zone and a virtual line source. The parabolic cylindrical reflector can correct the cylindrical wave formed by the spherical wave emitted by the feed source in the quiet zone. In order to control the diffraction of the edge of the reflector, the edge of the parabolic cylindrical reflector needs to be processed. The crimped edge of the parabolic cylindrical reflector can reduce the low-frequency limit of the cylindrical wave tight field. Compared with the sawtooth cylindrical wave tight field, the electric size of the reflector working at the low-frequency limit is smaller, and the engineering realization of the large cylindrical wave tight field is more favorable.

This invention relates to the field of wireless communication technology, and provides a shaped antenna reflector and a reflector antenna, having a shaped reflector surface, including a parabolic reflector surface that is at least a portion of a semi-parabolic rotator and a swept reflector surface that is at least a portion of a swept surface; the generatrix of the semi-parabolic rotator is a parabolic segment whose vertex is on the parabola, and the semi-parabolic rotator is formed by rotating the generatrix by 180° about the axis of symmetry of the parabola; the edge of the parabolic reflector has a connecting edge that is located on the same parabola as the generatrix, and the swept surface is formed by sweeping the connecting edge in a direction away from the parabolic reflector surface, and the swept reflector surface is tangent to the parabolic reflector surface at the connecting edge; the shaped reflector surface is used to reflect spherical waves emitted from the feed on the concave side of the parabolic reflector surface, the reflected beam is a deformed cosecant square beam in a first plane direction and a narrow beam in a second plane direction, the first plane direction is consistent with the direction of the central symmetry plane of the semi-parabolic rotator, and the first plane direction and the second plane direction are perpendicular.

This invention provides a double-layer symmetrical cross-shaped metasurface element and a high-gain wide-beam metasurface reflective antenna. The antenna includes a conical horn feed and a reflective array, the reflective array being composed of multiple reflective metasurface elements. The metasurface elements employ a symmetrical double-layer cross-shaped metal patch structure with an air gap between the two patches. Continuous modulation of the reflected phase of the incident electromagnetic wave is achieved through electromagnetic coupling between the multi-layer structure. The reflective array is designed with phase compensation based on the spatial phase distribution of the feed antenna, converting the reflected wave from a spherical wave to a quasi-plane wave, thereby achieving directional radiation and extending the beam coverage. This invention features a compact structure, low loss, and can achieve synergistic optimization of high directional radiation and a wide beam under limited aperture conditions, making it suitable for applications such as emergency communications.

This invention belongs to the field of antenna performance testing technology, specifically disclosing a method and system for calculating the ground effect of a vehicle antenna based on spherical near-field measurements. The method includes: measuring the vehicle antenna in a full-wave spherical near-field anechoic chamber to obtain the ground effect of the antenna under test. r The spherical near-field component at 0; the coefficients of the spherical wave mode are obtained using spherical wave expansion; the antenna under test is calculated at... r The electric and magnetic fields at point 1 r 1 <r 0; and transform the electric and magnetic fields in spherical coordinates into rectangular coordinates; calculate the normal vector of each equivalent source point; and calculate the radius by combining the rectangular coordinates of the electric and magnetic fields respectively. r The equivalent current and equivalent magnetic current on the sphere are calculated; then the mirror equivalent current and mirror equivalent magnetic current are obtained respectively; the far field of the equivalent source and the mirror source are calculated, which is the antenna pattern of the vehicle antenna under the PEC ground. The method of this invention does not require the establishment of integral equations, the calculation process is simple, and the computer resource requirements are low.

The present application relates to the technical field of open blasting, in particular to a method and system for optimizing construction scheme of reducing row and pull damage after open blasting. The method comprises the following steps: obtaining a geological stability coefficient by using a variation coefficient to dynamically weight basic parameters of geological stability; constructing a spherical wave energy attenuation model to obtain effective impact energy density by using the spherical wave energy attenuation model; calculating a free surface effect coefficient by free surface form parameters, and obtaining a rock mass blasting response principal component according to a principal component analysis algorithm based on the geological stability coefficient, the effective impact energy density and the free surface effect coefficient; calculating a damage disturbance synergistic effect coefficient in combination with an instantaneous damage degree and an environmental disturbance comprehensive index; and obtaining a construction scheme of reducing row and pull damage after open blasting by a particle swarm optimization algorithm based on the rock mass blasting response principal component and the damage disturbance synergistic effect coefficient. The present application solves the problem of accurately controlling the risk of row and pull damage.

Systems and methods of optical metrology and inspection are provided, including shaping a pump pulse to have a concave wavefront that generates, in a sample, an acoustic wave that converges at a focal location. When a subsurface feature is at the focal location, a reflected acoustic wave is generated, with a convex acoustic wavefront. A probe assembly is configured to shape a probe pulse to have a spherical wavefront and to impinge on the surface simultaneously with the return to the surface of a reflected acoustic wave. A detection assembly is configured to receive a reflected probe pulse, reflected from the surface, and, responsively, to determine whether the reflected probe pulse is indicative of surface changes induced by a reflected acoustic wave from a subsurface feature at the focal location.

The application provides an optical neural network module based on phonon polariton regulation and a design method, comprising a heterostructure of a waveguide, a phase change material and hexagonal boron nitride, layers of the neural network are connected through diffraction of phonon polaritons, each unit on the diffraction layer is a sub-wave source of a secondary spherical wave; input of a neuron of an arbitrary layer is output of all neurons of a previous layer, and the input is superimposed on the neuron after diffraction; weight of each neuron is defined as influence of a unit structure on the diffraction layer on phase and amplitude of the phonon polariton; input data is input from an input layer, propagation of waves between diffraction layers is calculated, and output results of an output layer are obtained; then, weight of a neuron of each diffraction layer is continuously optimized through an error back propagation algorithm, a trained neural network is obtained after several cycles, and the neural network result is written on the phase change material through laser with different wavelengths and powers.

This invention relates to a method and system for locating hot cracks in DED thin-walled parts based on multi-source acoustic emission. The method includes: arranging at least three air-coupled acoustic emission (AE) sensors non-collinearly above the DED forming stage, and pre-calibrating the three-dimensional spatial coordinates of each AE sensor; during the layer-by-layer deposition of the thin-walled part, synchronously acquiring acoustic signals radiated into the air when hot cracks initiate using the AE sensors, and preprocessing the acoustic signals; extracting pulse characteristic signals characterizing hot crack initiation from the preprocessed multi-channel acoustic emission signals, and calculating the time difference between multiple pulse characteristic signals acquired by each AE sensor; constructing a spherical wave hyperbolic positioning equation set, and obtaining the height coordinates of the upper surface of the thin-walled part where the hot crack source is located; and calculating the spatial coordinates of the hot crack source based on the three-dimensional spatial coordinates of each AE sensor, the time difference of each pulse characteristic signal, and the height coordinates.

This invention provides a method for estimating seismic energy based on generalized spherical wave propagation, relating to the field of earthquake engineering. This method determines the initial total energy and seismic power of an earthquake based on its source characteristics and magnitude; it determines the generalized spherical wave equation and calculates the average energy flux density based on this equation; it treats the Earth's surface spherical cap projected onto the source surface as the main influence range of the seismic spherical waves on the surface, equates it to a square, and divides it into grids. The source distance between the center of each grid and the source center is calculated, forming a source distance matrix; the generalized spherical wave energy flux density of each grid is expressed as the sum of the energy flux densities of P-waves and S-waves; the grid is further subdivided to estimate the average amplitude of each subdivided grid mass unit during the seismic period, thus assessing the seismic energy at the site. By defining the generalized spherical wave propagation of source energy, the method estimates the effect of seismic energy on the Earth's surface, providing a more accurate assessment of the distribution of seismic energy on the surface.

The method for modeling complex scattering channel in airplane cabin under electromagnetic constraint and freedom degree analysis belongs to the cross technical field of wireless communication channel modeling and electromagnetic information theory, and aims to solve the problem that the current airplane cabin internal communication system lacks channel model for algorithm design. The method is based on Green function and distribution of electromagnetic excitation source in space to determine the electric field distribution of any point; the spherical wave is equivalent to the superposition of plane waves radiated in each direction, the Green function is expressed as the combination form of plane waves according to the decomposition of spherical wave, and then the electric field expression when the excitation source is an impulse current source is obtained; based on the eigen solution of homogeneous Helmholtz equation, the response value corresponding to the wave number direction is divided into two hemispheres according to space, and then the receiving channel coefficient expressed by the combination of eigen functions is obtained, the channel model is connected with the electromagnetic wave space distribution according to the receiving channel coefficient, and the channel model meeting the electromagnetic distribution constraint is obtained.

The invention belongs to the technical field of wireless communication, and particularly relates to a near-field low-complexity hybrid precoding method and system based on virtual subarray division. According to the method, virtual sub-array division is carried out on an antenna array, angle domain wave beam selection and combination are carried out on a sub-array layer in a layered array response modeling mode combining plane wave modeling in sub-arrays and spherical wave modeling between the sub-arrays, an analog pre-coding matrix is generated, and a mixed pre-coding structure is formed in combination with digital baseband pre-coding. The corresponding system comprises an antenna array, a radio frequency link and a baseband processing unit, wherein the baseband processing unit comprises a virtual sub-array division module, an array response modeling module, a sub-array angle domain beam construction and selection module and a hybrid precoding calculation and execution module. According to the invention, under the condition that a high-dimensional angle-distance joint codebook does not need to be constructed, near-field hybrid precoding design is realized, the calculation complexity and the precision requirement of a phase shifter are reduced, and the adaptability to a spatial non-stationary channel is improved.

The present application relates to the field of optical precision detection technology, especially to a Shack-Hartmann wavefront sensor core parameter calibration method and device, through the superposition calibration based on plane wave and spherical wave, the micro-lens array and camera target surface distance, micro-lens unit size which are strongly related to detection accuracy can be obtained, and the theoretical model has high precision.In the calibration scheme, by removing / adding a microscope objective, simple and fast switching based on plane wave and spherical wave can be realized, and the introduced error source is very small.In the calibration scheme, high-precision angle monitoring based on a collimator and high-precision displacement monitoring based on a displacement sensor are set, thereby ensuring high-precision calibration.

This invention describes a 3D stereoscopic hyperdirectional antenna and its optimization method. It includes: a multilayer substrate, several radiating elements, and an excitation module; the radiating elements are mounted on the multilayer substrate to form a 3D stereoscopic radiating element array; the excitation module includes an excitation circuit and a computing unit; it records the radiation field generated when the 3D stereoscopic radiating element array is uncoupled and the uniquely excited radiation field of different radiating elements when coupling exists; it expands the radiation fields before and after coupling using spherical wave coefficients to establish the connection between the coupled and uncoupled electromagnetic fields, obtaining a coupling matrix; it calculates and generates a hyperdirectional excitation vector based on the coupling matrix, thereby exciting the radiating elements through the excitation circuit to achieve hyperdirectional beam generation. Compared with existing antenna technologies, the hyperdirectional array excitation vector proposed in this invention can dynamically realize hyperdirectional beams with aligned directions, exhibiting excellent performance in both directivity and achievable gain.

The application discloses a target detection and channel estimation method of a near-field sensing and communication integrated system, and comprises the following steps: a base station sends a downlink pilot signal to a sensing target and receives a corresponding echo signal; then a user sends an uplink pilot signal and a user channel is estimated; according to the characteristics of a near-field channel, a sensing and communication signal model is established based on a spherical wave front assumption; according to the characteristics of the near-field channel, firstly, a Fresnel approximation is adopted to approximate the near-field channel model, then a low-overhead dictionary based on a near-field spherical wave approximation is proposed, and on this basis, an improved orthogonal matching pursuit algorithm is designed for the near-field communication sensing to estimate the parameter estimation method of the sensing target and the communication channel. The application can estimate the parameters of the near-field sensing target and the channel with low overhead, and improves the estimation precision of the parameters in the near-field scene.

The application discloses a kind of tilting wave surface infrared interference detection methods of double optical fiber interference arm, it is related to the field of optical precision measurement.The light emitted by wavelength tunable laser passes through coupler and is divided into two beams, one is directly output by polarization maintaining optical fiber as reference light, the other is incident to optical fiber array and outputs multiple standard spherical waves with different tilt angles as test light, compensates the surface gradient of different regions of the measured surface, thereby reducing the interference fringe density.Both the reference arm and the test arm of the system use optical fiber as an ideal point source generator, which can control the on-off of the point source and reduce the system error introduced by the use of lenses.The light emitted by the test arm optical fiber is all used as test light, which improves the utilization rate of the point source, increases the aperture of the measured surface, and realizes surface shape detection without moving the interference device, reducing the error introduced by mechanical movement.The system uses infrared light as the measurement beam to improve the dynamic measurement range, which can meet the detection of more gradient-changing large-aperture components.

The application provides a non-far-field-based SAR data calibration method and device, acquires SAR original echo data, trajectory data of radar motion and geometric parameters of target imaging; constructs a non-far-field radiation response model based on the trajectory data and the geometric parameters, and constructs a corresponding compensation function; performs non-far-field radiation compensation and imaging processing on the original echo data according to the compensation function, to obtain a first image; calculates a radiation calibration coefficient according to the first image, and performs radiation calibration on the first image according to the radiation calibration coefficient. The radiation response model of the target can be established under the non-far-field condition, the influences of factors such as the changing distance between the target and the radar, spherical wave propagation, the change of the directional diagram and the change of the viewing angle on the image intensity are analyzed and compensated, so that the radiation calibration suitable for the vehicle-mounted SAR scene is realized.

This application provides a device, method, and system for calibrating the geometric position of the center of a spherical wave, belonging to the field of optical measurement technology. The device includes a spherical wave point light source, a mask, an image sensor, and a relative displacement mechanism. The mask is placed between the spherical wave point light source and the image sensor, and the center of the first plane of the mask is aligned with the center of the second plane of the image sensor along the camera's optical axis. The mask includes a foreground layer and a background layer, wherein the foreground layer and the background layer have different transmittances. The foreground layer has a mask pattern, including a circular array and topological anchor points for source tracing. The relative displacement mechanism is used to change the planar distance between the mask and the image sensor along the camera's optical axis. The image sensor is used to acquire the light and shadow images formed by the incident light from the spherical wave point light source passing through the mask at different planar distances. The device structure and operation of this application are simple, reducing costs and achieving accurate calibration of the sphere's center position.

This invention provides a method and system for adaptive control of urban soundscape based on multi-source data, belonging to the field of urban soundscape control technology. The method includes acquiring acoustic audio data and visual image data synchronously collected by sensing units deployed in urban spatial nodes, and generating multi-source sensing data streams through timestamp alignment processing. This invention completely breaks through the defects of misjudgment and coordinate blind spots that are easily generated by single environmental sound pickup sensors in the background noise of complex human voice and traffic flow from the data mining and computing level by constructing a hidden layer alignment logic architecture of multimodal tensor addition of the underlying audio logarithmic spectrum diagram and visual spatiotemporal continuous features. Furthermore, by using urban dielectric impedance fading constant distribution layer data to perform spatial spherical wave back radiation energy subtraction model simulation calculation, it creatively replaces blind network broadcasting with digital mapping simulation addressing.

The application discloses a multi-aperture wireless optical communication transmission optimization method based on microwave feedback performance parameters and relates to the technical field of wireless optical communication.The application divides a light beam into multiple sub light beams and simultaneously constructs a distributed off-axis parabolic mirror (DOAP); the sub light beams are overlapped with the edges of the DOAP to form edge sampling units, edge spot data is captured, and pointing error information of the sub light beams is calculated; based on the error information, the sub light beams are precisely adjusted and aligned through an SPGD algorithm; after the precise alignment, each sub-aperture piston phase is set as a discrete spherical wavefront distribution, the sub light beams are transmitted to a receiving end to complete coherent synthesis; after the receiving end performs beam shrinking processing, single-mode fiber coupling and electrical signal conversion on the synthesized light spot, the synthesized light spot is returned to the transmitting end; the transmitting end takes the returned electrical signal as an SPGD algorithm evaluation function, iteratively corrects wavefront aberration caused by atmospheric turbulence, and realizes long-distance stable coherent synthesis and communication link establishment.The application can effectively correct wavefront aberration caused by atmospheric turbulence and has wide application value.

This invention belongs to the field of wireless communication and array signal processing technology, specifically relating to a low-precision phase shifter codebook design method suitable for near-field MIMO. Addressing the problems of large size, high computational complexity, and strong dependence on high-precision phase shifters in traditional angle-range domain codebooks in near-field hybrid precoding, this invention constructs a low-precision analog domain codebook based on the complex Hadamard transform of conjugate symmetric sequences, ensuring that codeword elements are taken only from [specific data type], thus supporting 2-bit phase shifter implementation. Furthermore, it improves beam coverage density by constructing an overcomplete codebook and combines it with a virtual subarray structure to perform beam selection at the subarray scale to adapt to the propagation characteristics of near-field spherical waves. This invention achieves good precoding performance under near-field and spatially non-stationary channel conditions while reducing hardware cost and power consumption, making it suitable for ultra-large-scale MIMO and near-field hybrid precoding systems.

This invention discloses a three-dimensional dynamic shape measurement device and method based on four-wave shearing interferometry projection, belonging to the field of three-dimensional shape measurement technology. The device includes a four-wave shearing interferometry fringe projection system, an image acquisition system, a computer, a test object, and a reference background plate. The projection system consists of two sets of interchangeable components. The optical interferometry projection system includes a laser diffraction component, a converging lens, a two-dimensional phase grating, and a four-aperture plate. The laser diffraction component generates spherical waves, which are converged and then diffracted through the two-dimensional phase grating. After filtering by the four-aperture plate, the four beams shear and interfere with each other to form a four-wave shearing interferometry image, which is projected onto the test object on the reference background plate. The image acquisition system acquires the interferogram and processes it with the computer to obtain the object's height information. This invention utilizes instantaneous shearing interferometry technology, requiring only a single image after calibration to complete the measurement, achieving true dynamic measurement. Furthermore, the accuracy is improved through optimized calibration and algorithms.

This invention discloses a near-field RCS measurement calibration method based on scattering center topological mismatch compensation. Addressing the systematic error problem introduced by the mismatch between the distributed scattering characteristics of the complex target and the ideal point source calibration body when using traditional metal sphere calibration, a physical model of calibration error incorporating near-field spherical wave effects is established. The method preprocesses data by extracting scattering centers and removing outliers, generates a global initial search point set using feature analysis of the error function sensitivity tensor, and performs local precise optimization using an improved parallel LM algorithm. Finally, it obtains the optimal spatial position parameters of the target that minimize measurement error. This method effectively compensates for RCS amplitude oscillations and phase distortion caused by phase center mismatch, reducing the root mean square error (RMSE) of RCS measurements for complex targets such as ship hulls from approximately 15% to below 5% in the Ka-band, significantly improving the accuracy and reliability of electromagnetic scattering characteristic measurements in the field and anechoic chamber.

The application discloses a method and system for locating a sound source outside a domain based on virtual array shift and deep learning fusion. The application acquires multi-channel acoustic signals and array geometric parameters; a coherent multi-frequency phase difference consistency positioning algorithm is used to coarsely locate the sound source, and an initial coarse positioning coordinate of the sound source is obtained; a virtual microphone array position is constructed according to the coarse positioning coordinate, time delay compensation and amplitude compensation are performed on each channel signal based on a free field spherical wave propagation model, virtual array receiving signals are generated, the sound source outside the domain is mapped to the recognition domain of a deep learning model under the virtual array coordinate system; the virtual array receiving signals are input into an attention-enhanced fusion neural network, and three-dimensional coordinates of the sound source under the virtual array coordinate system are output; and based on the coordinate transformation relationship between the virtual array and the real array, the final three-dimensional positioning coordinate of the sound source is obtained. The application improves the three-dimensional positioning accuracy of the sound source outside the domain and the positioning stability in a complex real environment.

This invention discloses a wavefront reconstruction method and apparatus for aspherical surfaces based on TIE (Transient Image Estimation), relating to the fields of optical measurement and wavefront reconstruction technology. It addresses the shortcomings of existing aspherical detection technologies, such as system complexity, low efficiency, and difficulty in simultaneously meeting the core requirements of high precision, high fidelity, and engineering adaptability for aspherical detection. The method includes: obtaining the shear overlap region and its wavefront gradient based on the small shear assumption and shear amount; obtaining the full-aperture reconstructed gradient field based on the minimum distance from pixels in the non-overlapping region to the boundary of the shear overlap region, the preliminary full-aperture gradient distribution, and the smoothed gradient data of the overlapping region; obtaining the full-aperture wavefront phase distribution based on the wavefront phase estimation of the nth iteration, the optimized full-aperture intensity axial derivative, the Poisson equation, and the adaptive step size; converting the full-aperture wavefront phase distribution into optical surface shape deviation to obtain the wavefront reconstruction result of the aspherical surface under test.

The application provides a lens-free microscopic imaging system and method based on a random mask. The system comprises an LED array, a random mask, an image sensor and a reconstruction algorithm module. The LED array is arranged above a sample to be measured and is used for providing multi-angle spherical wave illumination. The random mask is integrated on a glass protective cover of the image sensor and is used for amplitude modulation of a light field passing through the sample to be measured. The image sensor is arranged below the sample to be measured and is used for collecting multiple low-resolution sample intensity images formed by sequential illumination of the LED array. The reconstruction algorithm module is used for: in the first imaging, receiving all the low-resolution sample intensity images and an initial random binary pattern, synchronously reconstructing a high-resolution sample image by an iterative phase recovery algorithm, and self-calibrating the initial random binary pattern in the first iterative imaging process to obtain a calibrated mask pattern; in non-first imaging, directly calling the calibrated mask pattern to reconstruct a high-resolution image of a new sample.

The application provides a method for determining a spherical wave initial phase coefficient, a hologram generation method and equipment. The method comprises: setting a cyclic calculation rule of the spherical wave initial phase coefficient; cyclically calculating the spherical wave initial phase coefficient according to the cyclic calculation rule; in each calculation process, comprising: forming a hologram of a sample image based on the initial phase coefficient in the current calculation process; obtaining a reconstructed image of the hologram and a spectrum of the reconstructed image; determining a main peak position in the spectrum; and after the cyclic calculation is terminated, taking the initial phase coefficient in the calculation process corresponding to the maximum distance between the main peak position and the center spectrum as the initial phase coefficient of the spherical wave. The initial phase coefficient of the spherical wave determined by the above method considers the speckle size and periodic characteristics of the reconstructed image, so that when a hologram is added to an input image using the initial phase coefficient of the spherical wave for initial phase calculation, the speckle and high-frequency artifact noise phenomena in the reconstructed image can be suppressed, and the visual perception of the reconstructed image is improved.