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

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 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 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 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 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 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.