432 results about "Virtual array" patented technology

In the context of array sensors such as radar, sonar, and communications receiver arrays, the present invention exploits the geometry phase components of radiated wavefronts associated with the signals of interest in order to reduce the bandwidth requirements for DOA and beamforming processing. Additionally, geometry phase is exploited in order to effectively increase the resolution of an array without changing the size of its physical footprint or the number of array elements. Other embodiments of the invention include the use of virtual array elements for increase in effective array size.

In the context of array sensors such as radar, sonar, and communications receiver arrays, the present invention exploits the geometry phase components of radiated wavefronts associated with the signals of interest in order to reduce the bandwidth requirements for DOA and beamforming processing. Additionally, geometry phase is exploited in order to effectively increase the resolution of an array without changing the size of its physical footprint. Other embodiments of the invention include the use of virtual array elements for increase in effective array size.

A system and method for a virtual omni-directional camera array, comprising a video control system (VCS) coupled to two or more co-located portable or stationary information processing systems, each enabled with a video camera and microphone, to provide a composite video view to remote videoconference participants. Audio streams are captured and selectively mixed to produce a virtual array microphone as a clue to selectively switch or combine the video streams from individual cameras. The VCS selects and controls predetermined subsets of video and audio streams from the co-located video camera and microphone-enabled computers to create a composite video view, which is then conveyed to one or more similarly-enabled remote computers over a broadband network (e.g., the Internet). Manual overrides allow participants or a videoconference operator to select predetermined video streams as the primary video view of the videoconference.

The invention discloses an estimation method of a co-prime array DOA (Direction Of Arrival) angle based on sparse reconstruction, and mainly solves the problems that a prior art is higher in operand, less in identification information source amount and large in passive location evaluated error, and needs more priori knowledge. The method comprises the realizing steps of forming a co-prime array by an antenna receiver; obtaining observation data to spatial signal sampling; receiving data vectors by a virtual array element obtained by observation data; dividing spatial grids to form over-complete bases; receiving a spare relationship between the data vectors and the over-complete bases by the virtual array element to build a spare restraint equation; resolving the spare restraint equation by adopting a convex optimization method to obtain sparest resolution; drawing a magnitude spectrogram by a relative relationship between the sparest resolution and the spatial angle to obtain a DOA angle value. According to the method provided by the invention, the passive direction-finding precision and operating speed can be improved under a condition of low priori knowledge, the number of the recognized information source can be improved, and the estimation precision of a signal direction angle can be improved in a low signal to noise ratio, therefore the estimation method can be used for target reconnaissance and passive location.

An on-board multibeam radar apparatus includes a plurality of beam elements that constitute an antenna transmitting a transmission wave and receiving an incoming wave being reflected and arriving from a target in response to the transmission wave, a control unit configured to select a beam element used for transmission and reception out of the plurality of beam elements so as to change a field of view, and a processing unit configured to apply a Fourier transformation to beam element data which are data of a received wave received through the beam element used for transmission and reception selected by the control unit based on the number of elements and the element interval of a desired virtual array antenna so as to create virtual array data, and to perform a predetermined process based on the created virtual array data.

The invention discloses a method for estimating target arrival angle of a multiple input multiple output (MIMO) radar, which mainly solves the problem of large signal processing capacity in the target positioning process of MIMI radar. The method comprises the following steps of: 1) obtaining a virtual array of echo of each receiving antenna by a matched filter bank; 2) constructing a data conversion matrix and a dimension reduction array according to position of transmitting and receiving array; (3) reducing dimension of the virtual array data by the dimension reduction array to obtain an effective array after dimension reduction; 4) constructing two sub-arrays by rotational variance of effective array, and deriving covariance matrix of data; 5) decomposing eigenvalue of covariance matrix to obtain signal sub-spaces corresponding to two sub-arrays; 6) deriving rotational invariant relationship matrix by least square method to obtain arrival angle of target. The dimension reduction matrix form constructed by the method has versatility; the computation quantity is reduced by the dimension reduction of data and the ESPRIT (estimating signal parameter via rotational invariance techniques) algorithm; the computation speed of MIMO radar is increased; and the real-time signal processing of the MIMO radar is made easier.

The invention relates to a direction-of-arrival estimation method on the basis of a uniform circular array, in particular to a direction-of-arrival estimation method for independent signals and coherent signals on the basis of the uniform circular array. The direction-of-arrival estimation method on the basis of the uniform circular array includes: preprocessing estimation parameters of direction-of-arrival; removing noise of pattern space; increasing aperture of the array and performing direction-of-arrival estimation to independent signals; and eliminating independent signals and performing direction-of-arrival estimation to coherent signals. The direction-of-arrival estimation method has higher estimation precision, the aperture of the array can be utilized more sufficiently, the loss of the aperture of the array due to array transformation of a virtual array is recovered, estimation performance can be improved further, calculation is simple and calculation quantity is low.

The invention discloses a co-prime array DOA (direction of arrival) estimation method based on interpolation virtual array covariance matrix Toeplitz reconstruction, and mainly solves a problem of information loss caused by the heterogeneity in a virtual array in the prior art. The method comprises the implementation steps: constructing a co-prime array at a receiving end; receiving an incident signal through the co-prime array, and carrying out the modeling; calculating an equivalent virtual signal corresponding to the signal received by the co-prime array; constructing an interpolation virtual array and carrying out the modeling; constructing a multi-sampling snapshot signals of the interpolation virtual array and a sampling covariance matrix; constructing a projection matrix, and defining projection calculation related with the projection matrix; constructing a reference covariance matrix according to all information in an original virtual array, designing an optimization problem based on the interpolation virtual array covariance matrix Toeplitz reconstruction, and solving the optimization problem; and carrying out the DOA estimation according to the reconstructed interpolation virtual array covariance matrix. The method improves the freedom degree and resolution of signal DOA estimation, and can be used for the passive positioning and target detection.

Failover is provided between groups of logical units of storage presented as virtual arrays. A primary virtual array has at least one primary virtual port coupled to a fabric, each primary virtual port having a source virtual port name and a source virtual port address. A secondary virtual array has one or more secondary virtual ports coupled to the fabric, each secondary virtual port having a secondary virtual port name and a secondary virtual port address. All data resident on the primary virtual array is copied to the secondary virtual array. If a failure occurs in the primary virtual array, the secondary virtual port names and LUN names and numbers are replaced with the primary virtual port names and LUN names and numbers. The fabric then updates its name server database so that the database associates the primary virtual port names and LUN names and numbers with the secondary virtual port addresses.

A system for measuring the height of bin contents includes transmitters for transmitting pulses of wave energy towards the upper surface of the contents and receivers for receiving echoes of the pulses and producing corresponding signals. The transmitters and receivers are distributed aerially above the contents. The system also includes a processing apparatus, for using the received signals to map the upper surface, that includes correlators that correlate pulse waveforms with the signals, and a beamformer. In one embodiment, the beamformer computes, from the signals considered as corresponding to echoes, of pulses from fewer synthetic transmitters, received at a synthetic receiver array, respective directions of arrival of the signals. In another embodiment, the beamformer computes respective directions of transmission and arrival of the signals, and the processing apparatus also includes a processor that selects, according to the computed transmission and arrival directions, which signals to use for the mapping.

The invention discloses a virtual array DOA estimation method based on an L type array. The method comprises the steps that 1, based on the shift invariant property, a subarray Zx and a subarray Zy of the L type array horizontally shift to obtain a virtual array Zx' and a virtual array Zy', rotation invariance of two sub signals is formed due to the shift invariant property of the subarrays, and the virtual subarray signals are equal to the L type subarray Zx and L type subarray Zy input signals multiplied by a twiddle factor respectively; 2, the output of the four subarrays are combined to form a virtual array output signal Z (t); 3, the signal subspace and the noise subspace can be described by decomposing the features of covariance matrixes output by the array, mutual correlation processing is carried out on the array output signal Z(t) to obtain Rzz, and eigenvalue decomposition is carried out to obtain signal subspaces; 4, the twiddle factor is solved through linear operation, and the signal wave arrival direction can be obtained through the diagonal element of the twiddle factor. According to the virtual array DOA estimation method, no spectral function needs to be calculated, the phenomenon that the wave arrival direction is indirectly calculated without searching for the peak value is avoided, the complexity is lowered, the equipment complexity and cost are reduced, and the positioning precision is high.

Data is transparently migrated between groups of logical units of storage presented as virtual arrays. A source virtual array has at least one source virtual port coupled to a fabric. Each source virtual port having a source virtual port name and a source virtual port address. A destination virtual array has one or more destination virtual ports coupled to the fabric, each destination virtual port having a destination virtual port name and a destination virtual port address. All data resident on the source virtual array is copied to the destination virtual array. The destination virtual port names and LUN names and numbers are then replaced with the source virtual port names and LUN names and numbers. The fabric then updates its name server database so that the database associates the source virtual port name with the destination virtual port address.

The invention discloses a height measurement method based on an array interpolation compression perception. The height measurement method mainly aims at solving a low elevation height measurement problem under a multipath environment, and especially under low signal to noise ratio and less snapshot environments. The method comprises the following steps of extracting a target signal from a radar echo; acquiring a spatial-domain sparse signal through cancellation and signal reconstruction; using a wave beam formation method to obtain a rough measurement target angle; according to the rough measurement angle, acquiring the spatial domain and dividing the spatial domain; using the array interpolation to acquire a virtual array; according to a matrix transformation relation, acquiring an interpolation transformation matrix and carrying out prewhitening processing on the interpolation transformation matrix; using a whitening interpolation transformation matrix and an observation matrix to acquire an observation signal; using a whitening interpolation transformation matrix and observation signal iteration operation to acquire a target signal estimation value; extracting a target angle from the target signal estimation value so as to acquire a target height. By using the method of the invention, sampling points of the target signal and computation intensity are obviously reduced; sidelobes of a signal power spectrum and a space spectrum are effectively reduced; the method can be used in target tracking.

The invention relates to a near field focusing beam forming positioning method. In the method, the response of a signal received by each array element of a virtual array in a frequency domain, to be processed, within the frequency band range [fmin, fmax] is firstly obtained based on an expansion towing array passive synthesized aperture method, and then a target is accurately positioned by utilizing the near field focusing beam forming positioning method, wherein the frequency band range [fmin, fmax] is selected according to the actual requirement, and only the conditions that fmin is greater than 0, and fmax is not greater than one half of data sampling rate are satisfied. The invention effectively combines the expansion towing array passive synthesized aperture method and the near field focusing beam forming positioning method together and meanwhile acquires the benefits brought by the two methods. Moreover, the beam forming arithmetic is realized in the frequency domain; a broadband signal is decomposed into a plurality of frequency point signals, and each frequency point within the signal frequency band range is processed, and finally, results are accumulated; and the processing performances, such as robustness, resolution and the like, are more superior to those of direct processing in a time domain.

The invention discloses a no-grid co-prime array DOA (direction of arrival) estimation method based on virtual array interpolation, and mainly solves a problem of information loss caused by the heterogeneity of a virtual array in the prior art. The method comprises the implementation steps: constructing a co-prime array at a receiving end; receiving an incident signal through the co-prime array, and carrying out the modeling; calculating an equivalent virtual signal corresponding to the receiving signal of the co-prime array; constructing an interpolation virtual array, and carrying out the modeling; constructing a multi-sampling snapshot signal of the interpolation virtual array and a sampling covariance matrix; constructing a projection matrix, and defining projection calculation correlated with the projection matrix; designing an optimization problem based on the minimization of the nuclear norm of the signal covariance matrix of the interpolation virtual array, and solving the optimization problem; and carrying out the estimation of the DOA according to the reconstructed covariance matrix of the interpolation virtual array. The method improves the DOA estimation freedom degree and resolution, and can be used for the passive positioning and target detection.

The invention discloses a nest multiple-input and multiple-output radar DOA estimating method based on compressed sensing. The implementing process includes the steps that (1), an emitting array and a receiving array of a nest multiple-input and multiple-output radar are determined by using an array element layout form of a nest array; (2), each pulse repetition period of the radar is matched with a filtering echo signal; (3), a covariance matrix matched with filtering output data is vectorized; (4), a matrix reconstruction method and singular value decomposition are adopted for obtaining noise subspace; (5), an L1norm bound term and an L2 norm bound term in a sparse recovery problem are constructed; (6), the target DOA is determined by solving the sparse recovery problem. The freedom degree expansion characteristic and the high resolution characteristic of compressed sensing of the nest array are used at the same time, and the estimating method can be used for accurately positioning targets with the number larger than the total number of virtual array elements through the radar.

The invention discloses an L-shaped ultrasonic array sensor for partial discharge location of a transformer. The ultrasonic array sensors are arranged in an L-shaped manner at equal intervals; the number of array elements (piezoelectric sensors) is 3-300; and an ultrahigh-frequency sensor is located on a right-angle inner side formed by the L-shaped ultrasonic array, shielded by metal around and provided with a matching layer on the bottom surface. The L-shaped array is subjected to virtual expansion by use of higher order cumulant technology; the expanded virtual array is subjected to direction estimation by a spatial spectrum estimation algorithm, then wave beam synthesis is performed on the estimated direction; and with assist of the electric impulse or ultrahigh-frequency electromagnetic wave signal generated by the partial discharge, the propagation delay of ultrasonic wave in transformer can be obtained so as to perform location. The follow-up hardware circuits of the sensor can be greatly reduced, and the manufacturing cost is saved; and moreover, the Gaussian color noise can be effectively inhibited, being beneficial to the practical use of array technology in the field of partial discharge detection.

The invention discloses a two-dimensional direction of arrival estimation method for a nested array based L-shaped antenna array, and belongs to the field of array signal processing. The implementation method includes the following steps: constructing a nested array based L-shaped antenna array, calculating a cross-covariance matrix by using signals received by different sub arrays of the constructed L-shaped nested array; correcting the obtained cross-covariance matrix, performing vectorization on the corrected cross-covariance matrix to generate a virtual array, constructing a plurality of equivalent covariance matrices by using the virtual array, calculating the signal azimuth angle Theta and the pitch angle Phi by using the rotation invariance between different equivalent covariance matrices, and achieving multi-target and high-precision two-dimensional direction of arrival estimation with few snapshots at a low signal-to-noise ratio. The technical problem to be solved by the invention is to realize multi-target and high-precision two-dimensional direction of arrival estimation by using fewer array elements at a low signal-to-noise ratio and with few snapshots, and to solve related engineering technical problems by using two-dimensional direction of arrival estimation results.

The invention aims to provide a low-complexity space target two-dimensional angle estimation method of L-shaped array MIMO radar. The method comprises the following steps that an L-shaped array is composed of two uniform linear arrays perpendicular to each other, the distance between every two adjacent array elements is a half of a wavelength, one linear array has M array elements, the other linear array has N array elements, all the array elements are receiving and sending co-located array elements, orthogonal narrow-band signals are sent, received signals are processed by means of matched filtering, and echo signals of a large-aperture virtual array are obtained; a dimensionality reduction array is designed, and dimensionality reduction is conducted on the echo signals; characteristic decomposition is conducted on a covariance matrix of dimensionality reduction signals, and a two-dimensional space spectrum function is obtained; a two-dimensional angle in the two-dimensional space spectrum function is decoupled, and space spectrum estimation is conducted on the angle of one dimension; an obtained space spectrum estimated value is substituted into the space spectrum function, and polynomial rooting estimation is conducted on the angle of the other dimension; according to the relation of trigonometrical functions, the azimuth angle and pitching angle of a target are obtained. The method greatly reduces computational complexity of algorithm, and is beneficial to real-time processing of a radar system.

Provided is a parameter estimation method based on a virtual concentric annulus array. A receiving array is composed of actual array elements distributed on two concentric circular arcs, the number of the actual array elements is an even number, each concentric circular arc comprises an inner circular arc and an outer circular arc, each inner circular arc and each outer circular arc are arranged on the different sides of a coordinate original point, and do not overlap with each other, a connecting line between the end point of each inner circular arc and the end point, far away from the end point of each inner circular arc, of each outer circular arc penetrates through the coordinate original point, a reference array element is arranged on the coordinate original point, and a connecting line of each actual array element on each inner circular arc and each corresponding actual array element on each outer circular arc penetrates through the coordinate original point. The parameter estimation method based on the virtual concentric annulus array comprises the following steps of (1) measuring a measurement phase difference between each actual array element and the reference array element, (2) determining a measurement phase difference between each virtual array element and the reference array element, (3) determining a virtual short basic line theoretical phase difference of an incoming signal, (4) determining a phase ambiguity multiple of a long basic line theoretical phase difference through the virtual short basic line theoretical phase difference, and (5) determining a long basic line accurate estimation phase difference according to the phase ambiguity multiple, and obtaining an estimated value of a two-dimensional arrival angle of the incoming signal according to the accurate estimation phase difference of the incoming signal on a long basic line.

The invention discloses a bistatic MIMO radar high-speed movement target parameter estimation method based on dual-frequency transmission. Echo signals of high-speed high-mobility targets are received through a receiving array of bistatic MIMO radar, and the echo signals of the receiving array are divided according to different carrier frequencies; conjugate multiplication is conducted on the two routes of echo data obtained through division, and whole cycle integration is conducted in a rapid time domain; Fourier conversion is conducted on the integrated data in a slow time domain, and each target speed is estimated; high-speed target matching filtering functions are set up; matching filtering is conducted on the echo signals of the receiving array to form a virtual array; the transmission angle of each target and the receiving angle of the target are estimated. The range walk of the high-speed targets is corrected according to the characteristic of the echo signals of the dual-frequency transmission MIMO radar, the problem that the parameter estimation performance is influenced by unstable factors such as Doppler spread and RCS rapid fluctuation is solved, and MIMO radar parameter estimation under the high-speed high-mobility targets is achieved.

The invention discloses a co-prime array wave arrival direction estimation method based on interpolation virtual array signal atom norm minimization. The objective of the invention is to solve the problem of an information loss caused by non-uniformity of a virtual array in the prior art. The method comprises following steps that a receiving end constructs a co-prime array; based on the co-prime array, an incidence signal is received and modeling is performed; an equivalence virtual signal corresponding to the a co-prime array receiving signal is calculated; an interpolation virtual array is constructed and modeling is performed; a multi-sampling snapshot signal of the interpolation virtual array and a sampling covariance matrix thereof are constructed; a projection matrix is constructed and projection calculation related to the projection matrix is defined; an optimization problem based on the interpolation virtual array signal atom norm minimization is designed and solved; and direction-of-arrival estimation is performed according to the reconstructed interpolation virtual array covariance matrix. According to the invention, the freedom degree and the resolution of the direction-of-arrival estimation are improved and the method can be used for passive positioning and target detection.

The invention discloses a MIMO radar antenna array sparse arraying method, which is based on almost difference sets and difference bases, and establishes a MIMO radar transmitting / receiving array rapidly through enumeration shifting process. When all transmitting array elements transmit orthogonal signals simultaneously and receiving array elements receive echo signals simultaneously, a virtual array with even space can be established equivalently by utilizing a phase center approximation principle; number of the transmitting / receiving array elements is given, the continuous aperture maximization of the equivalent virtual array can be realized according to the MIMO radar antenna array sparse arraying method, thereby improving spatial resolution of a MIMO radar system significantly; and the continuous apertures of the virtual array are given, and the minimization of number of the transmitting / receiving array elements can be realized according to the MIMO radar antenna array sparse arraying method, thereby reducing hardware cost of the system significantly. The MIMO radar antenna array sparse arraying method has small computational complexity, and is applicable to establishment of MIMO radar sparse linear arrays and planar array.

The invention provides a saw-tooth wave distance measuring and speed measuring method based on a 77GHz millimeter wave radar. The saw-tooth wave distance measuring and speed measuring method comprisesthe following steps: a. transmitting same frequency modulation continuous saw-tooth wave transmitting signals by Nt transmitting antennas in sequence and forming a virtual array; b. receiving echo signals of the transmitting signals by Nt receiving antennas and forming a virtual array YV which belongs to CNtNr*Ns*Nsa1, wherein Ns is equal to fsT and Nsa1 is a transmitting period; c. carrying outwindowing FFT (Fast Fourier Transform) on each transmitting period and a receiving signal of each antenna to obtain YVF which belongs to CNtNr*NqFFT*Nsa1, wherein NqFFT is a rapid time dimension FFT point number; d. carrying out slow time dimension FFT on receiving signals of different distance units of each receiving antenna to obtain YVFF which belongs to CNtNr*NqFFT*NsFFT, wherein NsFFT is a slow time dimension FFT point number; e. carrying out phase compensation on each distance-speed unit of the YVFF to obtain YVFFC which belongs to CNtNr*NqFFT*NsFFT; f. carrying out beam forming on all the distance-speed units to obtain Z which belongs to CNqFFT*NsFFT; g. carrying out constant false alarm CFAR detection on data obtained by the beam forming to obtain a constant false alarm detection result; h. substituting the constant false alarm detection result into an equation to obtain a speed v and a distance parameter r.

The invention provides a method for improving the anti-jamming performance of a satellite navigation array antenna, and aims to provide an anti-jamming method which can effectively suppress strong jamming and enhance the output signal-to-noise ratio of the antenna. The invention is realized by the following technical scheme: in a created array signal receiving model, each channel is sequentially subjected to a frequency conversion channel, A / D analog-digital conversion and data preprocessing time delay to obtain continuous space-time two-dimensional snapshot data, a plurality of virtual arrays are formed by data replication, each virtual array corresponds to an independent space-time two-dimensional anti-jamming module, each of the anti-jamming modules selects a different array element as the main array element and takes signals received by a channel of the array element as reference data, the space-time joint adaptive anti-jamming based on the power inversion is realized, the outputs of the anti-jamming modules are directly added by a secondary beam combining module, and finally the synthesized digital intermediate frequency signal is subjected to D / A digital-analog conversion and an up-conversion module to output an analog signal to a satellite navigation receiver at the back end.

The invention discloses a virtual array antenna based angle estimation method for improving accuracy. The virtual array antenna based angle estimation method is used for a large-scale uniform linear array based millimeter wave communication system, and the sparse characteristics of millimeter wave channels and a compressing reconstruction algorithm are utilized to estimate an antenna transmitting angle and an arrival angle of each channel of multiple channels by adding a plurality of virtual array elements on antenna arrays at the receiving end and the transmitting end. By means of the virtual array antenna based angle estimation method, the angle estimation accuracy can be improved, pilot frequency sequence expenditure can be reduced, and antenna array hardware change is not needed.

The invention relates to a MIMO radar distance-angle two-dimensional super-resolution imaging algorithm. The algorithm comprises the following steps: step 1, establishing a mathematic model for MIMO radar imaging; step 2, performing pulse compression by use of a multi-waveform self-adaptive pulse compression method, obtaining a distance image of an observation scene, and realizing separation of emitted waveforms to obtain a receiving signal of a MIMO radar virtual array; and step 3, at a virtual array end, performing orientation focusing on echo signals of different distance units by use of a super-resolution space spectrum estimation algorithm to finish high-resolution distance-angle two-dimensional focusing imaging.

The present invention relates to a narrowband interference suppression method used for a passive synthetic aperture. The method comprises the steps of carrying out fast Fourier transform (FFT) on a signal received by an array element when a towed line array sonar is sampled at one moment, and estimating a center frequency and an interference band of narrowband interference; filtering the signal and reconstructing the filtered signal in a time domain; presetting the total number of frequency compensation; carrying out FFT and frequency-domain beam forming on the signal, and accumulating the frequency-domain beam forming result; after movement for certain time, carrying out FFT and frequency-domain beam forming on a sampling signal, and accumulating the frequency-domain beam forming result; calculating the total phase correction compensation to obtain an output result of an extended virtual array; carrying out coherent accumulation on the output result of the compensated extended virtual array to obtain a time azimuth history plot to detect a detected target signal, determining whether the current number of times of frequency compensation is the preset total number of frequency compensation, if no, changing a current frequency value, and re-executing until the current number of times of frequency compensation is the preset total number of frequency compensation.