36results about How to "Improve azimuth resolution" patented technology

The invention relates to a re-focusing and imaging method for an on-board radar without any hi-precision motion compensation system, which comprises two procedures: (1) SAR initial compound image creation based on de-gradient processing; (2) Doppler signal phase error is measured based on improved PGA arithmetic, and compound image re-focusing for phase compensation is carried out. The second procedure comprises the following steps: the compound images are input; the center of the target with the most intensive point goes through cyclic movement; a window is added; Fourier transformation is done for orientation; estimation is made on the phase error; the phase is corrected; inverse Fourier transformation is done to return the compound image area. The invention allows to get on-board L-SAR re-focused images with resolution of orientation obviously improved only by original signal data without any hi-accuracy on-board platform movement compensation system to provide the info on movement state of an airplane; and the higher the contrast in the images, the better the focusing effect will be. As the SAR wavelength of L wave section is longer and penetrating, the invention can play high role in military reconnaissance and monitoring any disaster in civil application.

The invention discloses a time division ground-based MIMO landslide radar imaging method based on IFFT and mix-match pursuit, and aims to solve the problems that an existing mountain landslide monitoring field imaging method is high in data processing complexity and uses too many antennas; aiming at a multi-target imaging pseudo shadow point problem, the method introduces the mix-match pursuit algorithm, thus greatly improving the imaging quality; the method comprises the following steps: building an equivalent random sparse transmit-receive array; building an echo signal acquisition model; range direction compression treatment; azimuth compression treatment; finishing two dimension object high resolution imaging. The advantages are that the method can reduce the array quantity, can reducehardware cost, can reduce the data processing complexity, and can improve the range and azimuth resolutions.

The invention discloses an imaging method. The imaging method comprises the following steps: S1, acquiring a vortex electromagnetic wave echo signal of a radar detection target; S2, preprocessing thevortex electromagnetic wave echo signal; S3, obtaining the position information of the radar detection target according to the preprocessed vortex electromagnetic wave echo signal; S4, obtaining azimuth angle information of a plurality of scattering points of the radar detection target according to the preprocessed vortex electromagnetic wave echo signals; S5, obtaining scattering point pitch angle information corresponding to each scattering point according to the position information and the azimuth angle information of the plurality of scattering points; and S6, mapping the pitch angle information of all the scattering points into a three-dimensional coordinate to reconstruct the three-dimensional image of the radar detection target. The invention provides a vortex electromagnetic wavethree-dimensional imaging method suitable for different distance detection.

The invention belongs to the field of a radar imaging technology, and discloses a compression perception multilayer ISAR imaging method based on BP optimization, for mainly solving the problems of noise sensitivity, high single-layer compression perception optimization time complexity and difficult sparse control parameters by use of conventional ISAR imaging. The specific realization process is as follows: preprocessing original echo data; determining an orientation resolution step factor sigma; initializing an encoding matrix M1 and a decoding matrix W2; performing training by use of a BP algorithm to optimize an encoding process and a decoding process; reconstructing an ISAR image by use of a compression perception theory; performing reverse Fourier transformation on orientation, and inputting obtained echoes into a next layer, and carrying out the training by use of the same principle; and outputting a high-resolution ISAR image at a final layer. According to the invention, the convergence speed is fast, high-resolution imaging can be realized under the conditions of a low signal-to-noise ratio and a small echo quantity, and the method can be applied to classification and identification of ISAR image objects.

The invention provides an underwater target azimuth estimation method based on a bat binaural positioning model. According to the frequency band of a transmitting signal, a binaural positioning model parameter suitable for processing a hyperbolic frequency modulation signal is calculated, combined with the theoretical positions of interference peak and valley points in an echo signal, an external ear valley value frequency interval and the frequency response of an acoustic transducer are determined, and finally the azimuth of a target is calculated according to the external ear valley value frequency calculated by the model. According to the underwater target azimuth estimation method, the azimuth discrimination of the binaural positioning model is improved, thus an active sonar can achieve good azimuth discrimination in the condition of double array elements, and the performance is much better than that of a conventional beamforming method.

An onboard ultra-wideband radar front-view imaging system comprises a radar radiofrequency front end including an antenna, a frequency synthesizer, and a switching circuit, wherein the antenna is usedfor transmitting and receiving an ultra-wideband continuous wave signal, the frequency synthesizer includes a transmitter and a receiver, and the switching circuit is used for achieving the multi-transmitting multi-receiving time-sharing operation; an information processing unit including a signal processor and a data processor, wherein the signal processor is used for generating system timing control and a large-bandwidth step-frequency signal, sampling a radar step-frequency echo signal, and finally performing a near-field front-view imaging process and transmitting a result to the data processor, and the data processor processes the signal and detects the signal by a detection algorithm in the image domain, and finally detects and identifies positive and negative obstacles and obstacles behind hidden objects such as leaf leafages. The onboard ultra-wideband radar front-view imaging system is easy to achieve, good in environmental sensing effect and high in resolution.

The invention relates to a multi-layer co-sparseness-based inverse synthetic aperture radar high-resolution imaging method. The imaging process of the imaging method includes the following steps that: motion compensated and distance compressed echo data are inputted; the analytical operator of each distance unit of the echo signals is learned, and the echo data are de-noised; and after an optimal resolution operator and de-noised echo signals are obtained, a modified OMP algorithm is adopted to restore an ISAR (inverse synthetic aperture radar) image. During the whole imaging process, the imaging process of the method of the invention is divided into a plurality of stages; and a low-resolution ISAR image obtained at the previous stage is converted to an image in the data domain through inverse Fourier transformation, and the image is adopted as the input as the next stage. With the method of the invention adopted, the azimuth resolution of each stage is improved compared with the previous stage. The method of the invention can be used for the ISAR target imaging of sparse conditions and has strong robustness to noises.

The invention provides a synthetic aperture laser radar imaging method, instrument and system. The method comprises the following steps of transmitting a laser signal through an optical telescope arranged on a synthetic aperture laser radar, and simultaneously receiving echo signals by adopting at least two optical telescopes arranged on the synthetic aperture laser radar along an azimuth direction; carrying out along track interferometry processing on the echo signals to obtain an along track differential interferometry phase; acquiring a slope distance direction speed error through the alongtrack differential interferometry phase, and acquiring a motion error caused by vibration by utilizing the slope distance direction speed error; respectively carrying out motion error compensation processing on the echo signals received by the at least two optical telescopes by utilizing the motion error in order to obtain at least two pieces of azimuth direction to-be-compressed data; and carrying out Doppler signal coherent combination on the azimuth direction to-be-compressed data to complete azimuth compression processing of imaging.

The invention discloses a THz clock synchronization frequency modification continuous wave lossless thickness measurement detection system, and aims at providing a terahertz thickness measurement imaging system that is simple in structure, stable, reliable, excellent in performance and capable of widely applied to multiple occasions, and can be used for performing lossless detection on special coating and structures in situ. The system is implemented via the technical scheme as follows: a clock module (1) generates two microwave drive signals synchronously inputting into a terahertz frequencymodification continuous wave transmission source (2) and a terahertz detector (3), to achieve synchronization of receiving and transmission clocks; and a polarized light path (4) performs polarizationon the terahertz signal, controls local oscillator modulation waveforms of the terahertz frequency modification continuous wave transmission source (2) and the terahertz detector (3), and thus the imaging radar with consistent terahertz frequency modification continuous wave receiving and transmission modulation waveforms and the ellipsometry frequency modulation continuous wave lossless detection thickness measurement system with inconsistent terahertz clock synchronization receiving and transmission modulation waveforms are achieved.

The invention discloses a scanning radar forward-looking imaging method based on spatial embedded mapping, which includes the following steps: converting an azimuth resolution improving problem into amatrix solving problem on the basis of echo range pulse compression and range walk correction; analyzing the singular value distribution of an antenna measurement matrix using the theory of singularvalue decomposition, determining the order of a spatial embedded matrix under the premise of retaining the information of the antenna measurement matrix to be maximum, and generating a spatial embedded matrix; using the spatial embedded matrix to extract the information of the antenna measurement matrix, reconstructing the antenna measurement matrix and an echo signal, reducing the order of the matrix, increasing the matrix-irrelevant characteristic, and improving the pathological property of the antenna measurement matrix; reducing the order of the antenna measurement matrix according to a data model of spatial embedded mapping, so as to reduce the computational complexity; and based on the least squares principle, calculating the scattering coefficient of a target, and quickly imaging the target in azimuth at high resolution.

The invention discloses a synthetic aperture radar imaging method and device. The method comprises the steps that the first angular velocity and the imaging time of the SAR are determined, wherein the first angular velocity is the angular velocity of azimuth beam scanning when the SAR carries out sliding beaming imaging; the second angular velocity is determined according to the maximum mechanical rotation angular velocity of the SAR, wherein the second angular velocity is the angular velocity of mechanical scanning of the SAR; the third angular velocity is determined according to the first angular velocity and the second angular velocity, wherein the third angular velocity is the angular velocity of electrical scanning of the SAR; and the SAR is controlled to carry out mechanical scanning and electrical scanning according to the second angular velocity, the third angular velocity and the imaging time, so as to acquire echo data; and sliding beaming imaging is carried out based on the echo data.

The invention relates to a maneuvering array orientation estimation method based on sparse Bayesian learning. The invention relates to the technical field of sonar detection, and the method comprises the steps of constructing a maneuvering array sparse signal model according to a sonar array shape and an array directional angle provided by a platform navigation system; based on Gaussian distribution hypothesis of received noise, establishing a maneuvering array sparse Bayesian learning framework, and determining a posterior distribution form of array received signals; and performing logarithm maximization operation according to the posterior distribution form of the array receiving signals to obtain a far-field target orientation. According to the invention, the maneuvering array orientation estimation problem is solved by using the thought of sparse Bayesian learning, the orientation estimation precision and the orientation resolution capability are effectively improved, and meanwhile, the ambiguity of the port and the starboard can be more effectively inhibited.

Described herein is an automotive radar system and related processing techniques utilizing a three channel switched antenna to improve the angular resolution of an azimuth tracking radar.

The invention discloses a Chirp Scaling-based multi-angle ultra-long bunching SAR super-resolution imaging algorithm. According to the algorithm, Doppler spectrum offset of an ultra-long bunching multi-angle SAR echo signal in direction is deduced and analyzed, multi-angle echo fusion is realized by using the offset, then multi-angle imaging of the fused signal is completed by using the Chirp Scaling algorithm, and finally, super-resolution imaging is performed on the multi-angle ultra-long bunching SAR by using an MUSIC spectrum estimation method, and an imaging result of the Chirp Scaling algorithm is verified. The processing process of the method is not approximated, aims at processing the ultra-long bunching multi-angle SAR, and evaluates quality of an imaged image, so as to prove effectiveness of the method effectively and intuitively.

The invention relates to a re-focusing and imaging method for an on-board radar without any hi-precision motion compensation system, which comprises two procedures: (1) SAR initial compound image creation based on de-gradient processing; (2) Doppler signal phase error is measured based on improved PGA arithmetic, and compound image re-focusing for phase compensation is carried out. The second procedure comprises the following steps: the compound images are input; the center of the target with the most intensive point goes through cyclic movement; a window is added; Fourier transformation is done for orientation; estimation is made on the phase error; the phase is corrected; inverse Fourier transformation is done to return the compound image area. The invention allows to get on-board L-SARre-focused images with resolution of orientation obviously improved only by original signal data without any hi-accuracy on-board platform movement compensation system to provide the info on movementstate of an airplane; and the higher the contrast in the images, the better the focusing effect will be. As the SAR wavelength of L wave section is longer and penetrating, the invention can play highrole in military reconnaissance and monitoring any disaster in civil application.

The invention discloses a forward-looking sea surface target angle super-resolution method based on sparse constraint. The method comprises the following steps: S1, establishing a forward-looking imaging azimuth echo signal model; S2, based on the maximum posterior probability of the sea surface target, establishing a target function; and S3, solving the target function by using a Newton-Raphson method. According to the method, Weibull distribution more suitable for sea surface clutter characteristics is adopted to represent the sea clutter characteristics; the sea surface target sparse super-resolution imaging method comprises the steps of obtaining a sea surface target scattering coefficient, representing prior information of the sea surface target scattering coefficient by adopting Laplace distribution, deriving a target function based on a maximum posteriori criterion, solving the target function through a Newton-Raphson iterative method, obtaining a target scattering coefficient iterative solution, and realizing sea surface target sparse super-resolution imaging. According to the invention, the azimuth angle resolution of the forward-looking sea surface target imaging of the real aperture scanning radar can be significantly improved, and an idea is provided for an airborne radar sea surface target super-resolution imaging method.

The invention belongs to the technical field of underwater acoustic equipment design and manufacturing and relates to a method for designing a strong interference suppression beamformer under a multi-target condition. The method comprises the following steps that: S1, a filtering matrix G belonging to CM*M is designed, the output y (t) of a filter is equal to Gx (t) has a spatial filtering characteristic, wherein t is equal to 1,..., N, and a matrix spatial filtering principle should satisfy one of conditions described in the descriptions of the invention; S2, a sparse super-resolution azimuth estimation algorithm is adopted; S3, spatial matrix filtering-based sparse super-resolution azimuth estimation is performed, namely, super-resolution azimuth estimation of a weak target in a strong interference environment can be realized by using spatial matrix filtering and a 1- type sparse approximate minimum variance algorithm; and S4, computer simulation and actual measurement test data verification of the algorithm are performed. The matrix filter with spatial filtering characteristics of the passband and the stop band is designed; a high-resolution sparse azimuth estimation algorithm is adopted, so that interference is effectively suppressed to the greatest extent in a signal processing process, the detection capability of a sonar on the weak target is improved, the output signal-to-noise ratio of the matrix is improved, and the remote detection capability of the sonar is enhanced.

The invention provides an adaptive wave beam stable Ku wave band phased array water surface target detection system. A radar array antenna array surface of the system is connected with a T / R assembly through a traveling wave coupling feeder line, the T / R assembly is connected with a wave control extension set and a correction front end, the wave control extension set is connected with a servo extension set and a display control extension set, the correction front end is connected with the T / R assembly and the traveling wave coupling feeder line, the correction front end is connected with a transmitting channel and a receiving channel, the transmitting channel is connected with the receiving channel, the receiving channel is connected with the signal processing extension set, the signal processing extension set is connected with the wave control extension set, the servo extension set and the display control extension set, the display control extension set is connected with the wave control extension set, and a modular power supply supplies power to the detection system. The detection system is small in size, can sense carrier attitude information in real time, and is stable in adaptive wave beam.

The invention discloses a mixed regularization azimuth super-resolution imaging method, which is applied in the field of radar imaging and aims at traditional L 2 Regularized imaging method has low resolution, traditional L 1 For the problem of poor anti-noise performance of the regularized imaging method, the present invention first establishes a convolution-like model of scanning radar azimuth echo; then, through L 2 The regularization method preprocesses the echo signal; finally, based on the preprocessing result, L 1 The norm characterizes the target sparse prior information to reconstruct the target function, and the method of iteratively reweighting the norm is used to solve the target function. The innovation of the present invention lies in: combining L 1 Regular term and L 2 The advantages of the regular term, use L 2 The norm weakens the influence of noise and avoids the noise being amplified in the iterative process, and then uses L 1 The sparse nature of the norm improves the azimuth resolution of imaging. This method is different from the conventional L 2 Compared with the regularization method, the azimuth resolution is improved, and compared with the traditional L 1 Compared with the regularization method, the noise is well suppressed.

The invention relates to a rectangular aperture telescope antenna for a synthetic aperture laser imaging radar, which comprises an objective lens pupil, an objective lens, an eye lens and an eye lens pupil. The objective lens pupil is positioned on the front focal plane of the objective lens; the eye lens pupil is positioned on the back focal plane of the eye lens; the objective lens pupil, the objective lens, the eye lens and the eye lens pupil have rectangular apertures; the focus of the objective lens is f1; the focus of the eye lens is f2; and the distance between the objective lens and the eye lens is f1 plus f2. The invention can generate a rectangular optical toe according with the scanning mode of the synthetic aperture laser imaging radar, eliminate the phenomenon of uneven imaging resolution and reduced resolution of the optical toe in the azimuth direction and the vertical motion direction, and design optimal scale of the rectangular apertures to respectively control the scale of the laser radar optical toe in the azimuth direction and the vertical direction motion, so as to obtain large scanning width and high azimuth direction resolution.

The invention discloses a time-division ground-based MIMO landslide radar imaging method based on IFFT and mixed-matching tracking, which is used to solve the problems of large number of antennas and high data processing complexity in the existing imaging methods in the field of landslide monitoring, and aims at the false detection of multi-target imaging. The shadow point problem introduces a mixed-matching tracking algorithm, which greatly improves the imaging quality. The realization steps are: constructing an equivalent random sparse transceiver array; establishing an echo signal acquisition model; compressing processing in the range direction; compressing processing in the azimuth direction; completing two-dimensional target high-resolution imaging. The invention has the following advantages: the number of arrays is reduced, the cost of hardware is reduced; the complexity of data processing is reduced; and the resolution of distance direction and azimuth direction is improved.

The invention discloses a multipurpose radar antenna system which comprises a plurality of antenna units, and part of the antenna units are transmitting multiplexing antenna units and are used as transmitting antenna units in radar antenna systems in different states. Part of the antenna units are transceiving multiplexing antenna units and are used as transmitting antenna units or receiving antenna units in radar antenna systems in different states. When the radar antenna system is in an unfolded state, a plurality of antenna units form a single transmitting array element or a single receiving array element, and a plurality of transmitting array elements and a plurality of receiving array elements form a transmitting-receiving antenna array element of an area array structure so as to carry out long-distance high-resolution reconnaissance; when the radar antenna system is in a folded state, one antenna unit forms a single transmitting array element or a single receiving array element, and a plurality of transmitting array elements and a plurality of receiving array elements form a transmitting and receiving antenna array element to perform close-range high-precision imaging reconnaissance. The system has the advantages of being simple in structure, easy and convenient to operate, adjustable in framework and suitable for long-distance and short-distance reconnaissance and the like.

The present invention provides a Ku-band phased array water surface target detection system with adaptive beam stabilization. The radar array antenna array included in the present invention is connected with the T / R component through the traveling wave coupling feeder line, and the T / R component is connected with a wave control The extension is connected to the calibration front end, the wave control extension is connected to the servo extension and the display control extension, the calibration front is connected to the T / R component and the traveling wave coupling feeder, the calibration front is connected to the transmission channel and the reception channel, the transmission channel is connected to the reception channel, and the reception channel It is connected with the signal processing extension, the signal processing extension is respectively connected with the wave control extension, the servo extension and the display control extension, the display control extension is connected with the wave control extension, and the modular power supply provides power for the detection system. The detection system of the present invention is small in size, can perceive the attitude information of the carrier in real time, and has stable self-adaptive beams.

The invention provides a synthetic aperture laser radar imaging method, instrument and system. The method includes: transmitting laser signals through an optical telescope arranged on the synthetic aperture lidar, and simultaneously receiving echo signals by using at least two optical telescopes arranged on the synthetic aperture lidar along the azimuth direction; The echo signal is subjected to along-track interference processing to obtain the along-track differential interferometric phase; the slant-range velocity error is obtained through the along-track differential interferometric phase, and the motion error caused by vibration is obtained by using the slant-range velocity error; The above motion error performs motion error compensation processing on the echo signals received by the at least two optical telescopes to obtain at least two azimuth image data to be compressed; perform Doppler signal coherent synthesis on the azimuth image data to be compressed , to complete the azimuth compression processing of the imaging.

A synthetic aperture interference near-field active source imaging method and device, the method includes irradiating a scattering target and receiving scattered echo signals; performing cross-correlation processing on the echo signals received by different receiving units to obtain a cross-correlation function; The curvature of the phase surface in the near field is corrected to obtain the corrected cross-correlation function; Fourier transform is performed on the corrected cross-correlation function to obtain the target brightness function; the target brightness function is transformed into the space Cartesian coordinate system to obtain the position of the target. The invention utilizes the symmetry of the baseline vector in the spatial wavenumber domain to expand the comprehensive aperture to ensure higher azimuth resolution, and utilizes the fast Fourier transform relationship to ensure the calculation efficiency of the method, thereby realizing the imaging method with high resolution and high timeliness.

The invention discloses a multi-purpose radar antenna system, which comprises a plurality of antenna units, some antenna units are transmitting multiplexing antenna units, which are used as transmitting antenna units in radar antenna systems in different states; some antenna units are transmitting and receiving multiplexing The antenna unit is used as a transmitting antenna unit or a receiving antenna unit in the radar antenna system in different states; when the radar antenna system is in the unfolded state, multiple antenna units form a single transmitting array element or a single receiving array element, and multiple transmitting arrays The antenna unit and multiple receiving array elements constitute the receiving and transmitting antenna array element of the area array structure for long-distance high-resolution reconnaissance; when the radar antenna system is in the folded state, one antenna unit constitutes a single transmitting The array element and multiple receiving array elements constitute the transceiver antenna array element for close-range high-precision imaging reconnaissance. The invention has the advantages of simple structure, easy operation, adjustable structure and suitable for long- and short-distance reconnaissance.

The invention discloses a direction finding method based on time sequence packet filtering and amplitude difference gradual approximation, which comprises four steps of grouping of long and short pulses, selection of filter coefficients, determination of a pulse group of the current target and determination of a target direction. According to the direction finding method based on the time sequence packet filtering and amplitude difference gradual approximation strategy, on the basis of the prior art, a single pulse group inside a CPI is subjected to regrouping filtering processing to reduce width restrictions on the CPI, the target detection direction resolution can be improved, and the detection target direction precision can be improved.

The invention discloses a direction finding method based on time sequence packet filtering and amplitude difference gradual approximation, which comprises four steps of grouping of long and short pulses, selection of filter coefficients, determination of a pulse group of the current target and determination of a target direction. According to the direction finding method based on the time sequence packet filtering and amplitude difference gradual approximation strategy, on the basis of the prior art, a single pulse group inside a CPI is subjected to regrouping filtering processing to reduce width restrictions on the CPI, the target detection direction resolution can be improved, and the detection target direction precision can be improved.

The invention relates to a regularization least square subspace crossing target direction finding method. According to the method, the Tikhonov regularization method and the least square subspace crossing algorithm are combined to process received signals of a shallow-sea sonar apparatus. On a basis of constructing a least square problem through the utilization of the subspace crossing principle, and then through the regularization method, optimal regularization factors are determined, so that detection and accurate positioning of shallow-sea targets are finally realized. According to the regularization least square subspace crossing target direction finding method of the invention, the Tikhonov regularization method and the least square subspace crossing algorithm are combined for form a new direction finding algorithm. Compared with routine wave beam formation algorithms, the method is better in direction resolution performance and higher in accuracy degree, and the value calculating is stable.