109 results about "Array aperture" patented technology

A foldable radiator assembly includes a flexible dielectric substrate structure having a radiator conductor pattern formed therein. The flexible substrate structure can be flexible for movement between a folded position and a deployed position, or can be fixed in position by dielectric structures. An excitation circuit excites the radiator conductor pattern with RF energy. Strips of the radiator assemblies can be used to form an array aperture.

Ultrasound probes that transmits/receives ultrasound pulses with frequencies both in a low frequency (LF) and a high frequency (HF) band, where the radiation surfaces of said HF and LF bands at least have a common region. Several solutions for transmission (and reception) of LF and HF pulses through the same radiation surface are given. The arrays and elements can be of a general type, for example linear phased or switched arrays, or annular arrays or elements with division in both azimuth and elevation direction, like a 1.5D, a 1.75D and a full 2D array. The LF and HF element division and array apertures can also be different.

The invention is a DOA estimating method to realize circle-angle positioning based on TD-SCMDA standard, firstly adopting multiple signal classifying and correcting algorithms to realize the DOA estimation of intelligent antenna circle-angle positioning; aiming at TD-SCMDA antenna being uniform circle array, converting the array cell-space uniform circle array into mode-space virtual uniform line array; according to eigenvalue and eigenvector characteristic of the data covariance matrix of the virtual line array, advancing a MUSIC algorithm based on mode-space virtual uniform line array and deriving the MUSIC algorithm power chart for the virtual line array and the general implementation algorithm for the mode-space MUSIC algorithm; according to the character of MUSIC algorithm inapplicable to the DOA estimation of relative signal source, advancing the correcting MUSIC algorithm based on the mode-space virtual uniform line array; finally aiming at the problem that the array aperture is small and that the resistance to array cell error disturbance is bad, caused by MUSIC algorithm, advancing four-order cumulant MUSIC algorithm and four-order cumulant correcting MUSIC algorithm based on the mode-space virtual uniform line array.

The invention provides a quick beamforming method capable of improving array resolution and gain, comprising the following steps: adopting the construction of a minimum redundant array to optimize an M-element uniform linear array into a P-element non-uniform linear array; carrying out FFT processing on primitive data of a P-element array; in a frequency domain, constructing a covariance matrix of data based on the uniform linear array in accordance with the array aperture extension characteristics of fourth-order cumulants; carrying out normalization processing on the beam space and carrying out estimation on a Bartlett spatial spectrum. By adopting the array aperture extension characteristics of the fourth-order cumulants, the invention realizes that the optimized element layout form is employed to obtain high resolution and overcomes the defects of high requirements of the original fourth-order cumulant-based methods on snapshots and great computational complexity to enable the computation process to be simple and easy to operate. When the signal to noise ratio is higher than the supercritical signal to noise ratio, the method of the invention has higher array gain than that of conventional beamforming. The normalization processing of the beam space realizes effective inhibition to background interference. The beamforming method of the invention is simple and easy to operate and is especially suitable for project application.

The invention relates to an L1/2-norm-based sparse linear array optimization method. The method is characterized by comprising the basic steps of determining an initial array and a weighting matrix, determining array weight vectors, judging whether the stimulus of head and tail array elements in the array weight vector is greater than a set stimulus minimum delta or not, judging whether an L1 norm for optimizing a difference between the previous and latter array weight vectors is smaller than a set error minimum xi or not, and determining the array element positions and stimulus of the sparse linear array. According to the method, the non-convex optimization problem of solution to an L1/2 norm is converted into a series of convex optimization problems of the L1 norm, so that a sparse array with lower sparsity can be obtained to reduce the number of actually required array elements on the premise of substantially keeping calculation unchanged; meanwhile, the head and tail array elements of the array are constrained and adaptively regulated under the condition of given array aperture, so that the problem of deficiency of the head and tail array elements of the sparse array in an iterative convex optimization process is well solved, and the method is particularly applied to the place of optimization of a large-sized antenna array.

An optical telescope system, method of actively, adaptively providing optical control to an array of articulated mirrors in a sparse aperture in the optical telescope system and a computer program product therefor. Array apertures are selected sequentially for imaging. Each aperture is temporally modulating at a unique/different frequency and, simultaneously, focal plane images are detected for each array aperture with known and separable temporal dependencies. The images are processed for the current set of said focal plane images to detect an image wavefront. The feeding back wavefront errors are fed back to aperture actuators for controlling the array.

A high-intensity ultrasonic transducer array which phase-conrol fucusing is composed of a big-aperture rigid spherical crown body with a geometric radium close to maximal scan depth, a centrol hole for installing the probe of ultrasonography B and several small holes distributed in the mode of multi-layer regular ring array with unequal spacings, and several array cells inlaid in said holes. Its advantages are correct location, flexible focusing, small array aperture, and high grating lobe suppressing power and sonic intensity gain.

The invention discloses TDM-MIMO radar system based on an optimized sparse array and a signal processing method thereof. The system is based on a sparse array, and optimizes array distribution by using a genetic algorithm; and optimized array distribution lowers sidelobe level and improves energy use ratio. The system transmits an LFMCW signal by using a TDM technology without sending an orthogonal signal and matching filtering at a receiving end, thereby making radar system structure less complex. When the number of array elements is specific, DOA performance of the system is superior to thatof a traditional uniform linear array MIMO radar system; under the condition of identical array aperture, the system has the same DOA performance as the uniform linear array MIMO radar system, and has higher angular resolution and more concise structure. Further, the signal calibration processing method provided in the invention can improve accuracy and resolution of DOA estimation of a mobile target by the system effectively under a condition of low signal to noise ratio.

The invention discloses a differential evolution algorithm-based uniform area array sparse optimization method. At present, a phased array radar sparse array optimization technology lacks differentialevolution algorithm optimization under a uniform area array model. The method comprises the following steps of 1, converting a real number code in a differential evolution algorithm into a binary code; 2, constructing a fitness function by using the sum of the planar peak value side lobe levels; and 3, drawing a sparse array element distribution map through the binary codes obtained after optimization, and further obtaining a three-dimensional directional diagram of the sparse array. According to the method, based on a differential evolution algorithm, an array aperture, the number of array elements and an array element interval are taken as constraint conditions, and the minimum plane peak sidelobe level is taken as an objective function, so that a sparse array element position distribution map and a sparse array three-dimensional directional diagram are obtained. Simulation results show that the method has the advantages that constraint conditions are met, the directional diagram does not have obvious grating lobes and obvious mutual coupling influence in a visual area, the performance is good, and the algorithm convergence speed is high.

The invention discloses a harmony search algorithm-based linear sparse array grating lobe inhibition method. The method comprises the steps of firstly, giving out a linear sparse array model comprising multiple constraints such as an array element number, an array aperture, an array element spacing and the like, and building an optimization model by taking the reduction of a PSLL of an array as anobjective function; and secondly, converting the array element spacing, namely an optimization independent variable into a new independent variable through a vector mapping method, building a linearsparse array grating lobe inhibition model with a higher optimization freedom degree on the premise of ensuring a feasible solution space to be unchanged, and performing optimization on the inhibitionmodel through an HS algorithm. Through iterative calculation, an optimal array layout for minimizing the sidelobe level of the array under the condition of meeting the multiple constraints is selected as an optimal solution, and an optimal direction graph is obtained according to the optimal array layout. The conversion of the optimization problem is performed by adopting the vector mapping method, so that the freedom degree of the problem is increased and the optimization efficiency is higher; the optimization is performed on the problem by adopting the HS algorithm, and through the iterative calculation, a better PSLL is obtained; and the method is high in convergence speed and good in robustness.

The invention discloses a stochastic radiation radar coincidence imaging method applied to the field of radar imaging technology. The invention aims to solve a problem of comparatively high matrix relevance of a radiation field under an array aperture with limited bandwidth since that the radiation field formed by a prior stochastic radiation field construction method has comparatively large redundant information. According to the invention, a space stochastic field is obtained through stochastic signals of a transmission space of a transmission antenna array and the radiation field changes stochastically over time on the basis of configured transmission signal parameters; distribution of a space-time two-dimensional stochastic radiation field is obtained according to the configuration ofan antenna array, parameters of transmission signals and target distance history and echo signals are obtained according to the distribution of the stochastic radiation field by a receiving antenna; and finally, a coincidence imaging result of a target scene is obtained according to the relation between the distribution of the stochastic radiation field and the echo signals. The method provided bythe invention ensures the orthogonality of stochastic amplitude and phase of transmission signals and enhances incoherence of an echo stochastic scattered field.

The invention discloses a P-norm noise source positioning identification method based on a weight correction parameter, relating to the technical field of noise source positioning. The positioning identification method includes step 1 eigenvalue decomposition sound source positioning recognition method; step 2 P-norm noise source signal reconstruction method; and step 3 selection of algorithm for weight correction parameter Epsilon. The characteristic subspace of each order and the subspace response function are obtained by characteristic decomposition, a subspace sound source vector reconstruction model is established for the characteristic subspace of each order, the reconstruction model is solved by the P-norm sparsity constraint of the weight correction parameter, the subspace sound source vector is forced to converge faster and more efficiently to the location of the real sparse source, and the more concentrated sparse solution of energy can be obtained; the effects of signal-to-noise ratio, measurement distance, array aperture and analysis frequency on the algorithm positioning performance are analyzed, the simulation result shows that the method can achieve the accurate estimation of the position and amplitude of different types of sound sources, and the stability is good.

The invention discloses a self-adaption anti-coherent interference technology based on characteristic component rejection. Firstly, characteristic decomposition is carried out on an antenna multichannel receiving data covariance matrix to judge the number of a big characteristic value; then, the characteristic vector corresponding to signals and coherent interference is searched in a characteristic vector group corresponding to the big characteristic value so as to subtract the characteristic vector from the covariance matrix; finally, diagonal loading is carried out on the covariance matrix removing signals and coherent interference components, and the loaded matrix is used for calculating a self-adaption weight, data is weighed, and specific steps are disclosed in the drawing. The method of the invention avoids cancellation of desired signals while inhibiting incoherent interference, does not have array aperture loss and does not need to master the direction priori information of coherent interference. The method only relates to characteristic decomposition and inversion operation but does not relate to high-order cumulant operation, so that the method has simple steps and small calculation amount; the device is simple and has low cost. In addition, the method of the invention receives and utilizes the coherent interference as a wanted signal so as to improve the receiving gain of a target signal, thus owning better receiving performance. The method of the invention can be realized only by downloading a program to a general signal processing board, is easy to popularize and only needs to programme on a programmable signal processing board; thus, the system is convenient to upgrade while the system structure is not changed. The method of the invention can be widely applied to a system with various kinds of receiving channel structures and has popularization and application value.

The invention discloses a high-resolution sonar location method based on a sparsity of an objective space and mainly solves the problems that a limited array aperture causes insufficient spatial resolution and a signal source coherence causes an inaccurate estimation of an objective location and calculating work of subspace decomposition and data volume are considerable in the prior art. According to the method, a projection matrix which is from a spatial spectrum vector quantity to a ranks synthesis data vector is constructed. By taking advantage of the apriori information of the sparsity of the space target and obtaining data of large signal to noise ratio through a matched filtering, the spatial spectrum vector quantity is carried out with peak detection through an iterative computation to obtain the high-resolution spatial spectrum vector quantity. The objective location can be achieved by taking advantage of the received index value of a peak element through the calculation to gain an objective azimuth angle and an objective pitch angle. The location method has the advantages of being low in the needed data size and calculated amount in the iterative process, suitable for a hardware implementation, high in angular accuracy and improving markedly the spatial resolution.

The invention is applicable to the technical field of signal processing, and provides a sparse-based space-time adaptive processing method. The sparse-based space-time adaptive processing method comprises the steps: constructing a virtual space-time snapshot according to a space-time snapshot covariance matrix of a co-prime array - co-prime pulse; constructing a sparse-based space-time adaptive processing filter according to the virtual space-time snapshot; and according to the space-time adaptive processing filter, performing estimation of clutter signals to obtain a detection signal. One embodiment of the present invention provides a sparse-based space-time adaptive processing method with repetition interval of a co-prime array and a co-prime pulse. As the co-prime array can provide thecapability of a greater array aperture, and the O(MN) freedom degree can be realized by means of only M+N*1 physical sensors. Therefore, by means of the above advantages, the sparse-based space-time adaptive processing method can significantly improve the estimation accuracy of a direction of arrival (DOA), and applies the co-prime array to the space-time adaptive processor (STAP) field, thus greatly reducing the number of snapshots, and reducing the system cost.

The method belongs to the technique areas of digital medical ultrasonic image processing. The characters are as follows. Based on non uniform sampling and delta-sigma transformation, the data storageunit is introduced to realize the dynamic receiving apodization by using the addressing method of multiple storage pages so as to restrain diffraction lobes caused by the array aperture and improve the quality of the ultrasonic image. The delta-sigma sampled data as the address of the apodization storage units are inputted. The apodization data of the focus P are stored into the related storage unit. Based on the page selection signal, the apodization data with different focus P are selected from the related storage units to form the output data stream, which form the composite wave after thelow pass filter and decimation.