检索结果-南通市图书馆

Direction synthesis in DOA estimation for monostatic multiple input multiple output (MIMO) radar based on synthetic impulse and aperture radar (SIAR) and its performance analysis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2008年第6期51卷 656-673页

作者： ZHAO GuangHui CHEN BaiXiao ZHU ShouPing national Key Lab for radar signal processing Xidian UniversityXi’an 710071China

A new direction synthetic method for monostatic multiple input multiple output (MIMO) radar is presented based on synthetic impulse and aperture radar (SIAR) system. Concerned with the monostatic MIMO radar which simultaneously emits orthogonal signals with multi-carrier-frequency and possesses sparsely distributed transmitting and receiving arrays with respective location, as well as the situation for the presence of multipath propagation in the low flying target’s echo, the method integrates the aperture of the transmitting arrays with the receiving arrays to form the digital beam-forming (DBF) in azimuth and elevation dimensions. And a study has been made of planar general MUSIC algorithm based on decorrelating the multipath signals of multi-carrier-frequency MIMO radar. Through compensat-ing the phase delay of both the transmitting and the receiving arrays and synthe-sizing the transmitting beam in two dimensions at the receiver, the angular resolu-tion and measurement accuracy are improved and the computational complexity is reduced after transforming the three-dimensional (3D) parameter estimation prob-lem into a two-dimensional (2D) one. Finally, the Cramer-Rao Bounds (CRBs) of DOA estimation for azimuth and elevation is put forward with the exsiting multipath propagation. Results of computer simulation demonstrate the validity of the new method.

关键词： SIAR monostatic MIMO radar multipath propagation super resolution general MUSIC algorithm Cramer-Rao Bounds

Interval interpolating wavelets with robust boundary filters

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2000年第3期43卷 287-296页

作者：水鹏朗保铮 State Key laboratory for radar signal processing Xidian University Xi'an 710071 China

This paper studies the mathematical mechanism of the generalized interpolating filters and gives the corresponding parametric representations. On the basis of the parametric representations, a novel criterion and algorithm are proposed to design interval interpolating wavelets with robust boundary filters. Furthermore, some examples are designed and their performances in data compression are investigated. Both the theoretical analysis and the experimental results show that such an interval interpolating wavelet can effectively suppress the boundary effect.

关键词： generalized interpolating filter interval interpolating wavelet boundary effect robustness.

Time-frequency characteristics based motion estimation and imaging for high speed spinning targets via narrowband waveforms

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2010年第8期53卷 1628-1640页

作者： ZHANG Lei , LI YaChao, LIU Yan, XING MengDao & BAO Zheng national Lab for radar signal processing, xidian university, Xi’an 710071, China national Lab for radar signal processing Xidian University Xi’an China

This paper focuses on the motion parameters estimation and inversed synthetic aperture radar (ISAR) imaging for the high-speed spinning targets via the time-frequency characteristics. Assuming that the translational motion is compensated with the available motion compensation techniques, then the residual part of translational motion and the spinning motion are estimated with high precision based on the timefrequency characteristics. Combining with the procedure of the motion estimation, a novel coherent timefrequency spectrum intensity redistribution method, coherent single range Doppler interferometry (CSRDI), is proposed, which provides higher resolution and sustain lower signal to noise rate (SNR) than the current approach. Numerical simulation confirms the validity and high precision of the proposed approaches.

关键词： ISAR time-frequency characteristics CSRDI motion estimation high speed spinning targets

Narrow-band radar imaging of spinning targets

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2011年第4期54卷 873-883页

作者： BAI XueRu,SUN GuangCai,WU QiSong,XING MengDao & BAO Zheng Key laboratory for radar signal processing,xidian university,Xi’an 710071,China Key laboratory for radar signal processing Xidian University Xi’an China

According to the characteristics of narrow-band radar echoes from spinning targets,this paper applies the complex-valued back-projection method to image *** it accumulates the sinusoidal phase of spinning scatterers effectively,this method can obtain high resolution *** resolution and required radar pulse repetition frequency (PRF) of this method are *** imaging of fast spinning targets,however,spurious peaks appear due to azimuth down sampling with a low ***,a signal model of azimuth down-sampled echoes is created according to the compressed sensing (CS) *** an imaging method based on orthogonal matching pursuit (OMP) is proposed according to the sparsity nature of ISAR ***,the effectiveness of the proposed methods is demonstrated using simulated data.

关键词： radar imaging spinning targets complex-valued back-projection compressed sensing orthogonal matching pursuit

Modified Omega-K algorithm for processing helicopter-borne frequency modulated continuous waveform rotating synthetic aperture radar data

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2015年第3期26卷 476-485页

作者： Dong Li Guisheng Liao Yong Liao Lisheng Yang Key laboratory of Aerocraft Tracking Telemetering & Command and Communication Ministry of EducationChongqing University national Lab of radar signal processing Xidian University

With appropriate geometry configuration, helicopter- borne rotating synthetic aperture radar （ROSAR） can break through the limitations of monostatic synthetic aperture radar （SAR） on forward-looking imaging. With this capability, ROSAR has extensive potential applications, such as self-navigation and self-landing. Moreover, it has many advantages if combined with the frequency modulated continuous wave （FMCW） technology. A novel geometric configuration and an imaging algorithm for helicopter-borne FMCW-ROSAR are proposed. Firstly, by per- forming the equivalent phase center principle, the separated trans- mitting and receiving antenna system is equalized to the case of system configuration with antenna for both transmitting and receiving signals. Based on this, the accurate two-dimensional spectrum is obtained and the Doppler frequency shift effect in- duced by the continuous motion of the platform during the long pulse duration is compensated. Next, the impacts of the velocity approximation error on the imaging algorithm are analyzed in de- tail, and the system parameters selection and resolution analysis are presented. The well-focused SAR image is then obtained by using the improved Omega-K algorithm incorporating the accurate compensation method for the velocity approximation error. FJnally, correctness of the analysis and effectiveness of the proposed al- gorithm are demonstrated through simulation results.

关键词： helicopter-borne rotating synthetic aperture radar(ROSAR) frequency modulated continuous wave (FMCW) improved Omega-K algorithm two-dimensional spectrum.

High-resolution algorithm based on temporal-spatial extrapolation

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2010年第1期21卷 9-15页

作者： Xueya Yang Baixiao Chen Feilin Qi national Key Lab for radar signal processing Xidian University Xi' an 710071 E R. China

To enhance the resolution of parameter estimation with limited samples received by a short passive array, an iterative nonparametric algorithm for estimating the frequencies and direction-of-arrivals （DOAs） of signals is proposed. The cost function is constructed using 12-norm Gaussian entropy combined with an additional constraint, 12-norm constraint or linear constraint. By minimizing the cost functions in the temporal and the spatial dimensions using corresponding iteration algorithms respectively, the sparse discrete Fourier transforms （DFTs） of temporal and spatial samples are obtained to represent the extrapolated sequences with much larger sizes than the original samples. Then frequency and angle estimates are obtained by performing the traditional simple methods on the extrapolated sequences. It is shown that the proposed algorithm offers increased resolution and significantly reduced sidelobes compared with the periodogram and beamforming based methods. And it achieves high precision compared with the high-resolution method with lower computational burden. Some numerical simulations and real data processing results are presented to verify the effectiveness of the method.

关键词： temporal-spatial extrapolation frequency estimation direction-of-arrival discrete Fourier transform.

radar group target recognition based on HRRPs and weighted mean shift clustering

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2020年第6期31卷 1152-1159页

作者： GUO Pengcheng LIU Zheng WANG Jingjing national laboratory of radar signal processing Xidian UniversityXi’an 710071China Xi'an Electronic Engineering Research Institute Xi’an 710100China

When range high-resolution radar is applied to target recognition,it is quite possible for the high-resolution range profiles(HRRPs)of group targets in a beam to overlap,which reduces the target recognition performance of the *** this paper,we propose a group target recognition method based on a weighted mean shift(weighted-MS)clustering *** the training phase,subtarget features are extracted based on the template database,which is established through simulation or data acquisition,and the features are fed to the support vector machine(SVM)classifier to obtain the classifier *** the test phase,the weighted-MS algorithm is exploited to extract the HRRP of each ***,the features of the subtarget HRRP are extracted and used as input in the SVM classifier to be *** to the traditional group target recognition method,the proposed method has the advantages of requiring only a small amount of computation,setting parameters automatically,and having no requirement for target *** experimental results based on the measured data show that the method proposed in this paper has better recognition performance and is more robust against noise than other recognition methods.

关键词： clustering group target recognition high resolution range profile(HRRP) mean shift(MS)

Estimation of DOA and Polarization Parameters with 2-Level Nested Vector-Sensor Array Based on Quaternion Model

在线全文

学校读者我要写书评

暂无评论

Transactions of Tianjin university 2016年第6期22卷 583-589页

作者：赵继超陶海红 national laboratory of radar signal processing School of Electronic EngineeringXidian University Xi’an 710071 China

The quaternion coherence problem exists in the data model of the conventional dimensional reduced quaternion estimation of signal parameters via rotational invariance techniques(DRQ-ESPRIT), and DRQ-ESPRIT would lose degrees of freedom(DOFs)when it is used to implement the spatial smooth operation. An improved DRQ-ESPRIT algorithm based on 2-level nested vector-sensor array is proposed in this paper. The quaternion coherence problem is solved by switching the multiplication sequence of spatial direction vector and electric field. Meanwhile, nested array and Khatri-Rao subspace approach are used to increase the number of DOFs, thus the proposed algorithm can estimate more incident sources than DRQ-ESPRIT, and the estimations of direction of arrival(DOA)and polarization parameters are more accurate. Simulation results demonstrate the effectiveness of the proposed algorithm.

关键词：天津大学学报英文版

Unparallel trajectory bistatic spotlight SAR imaging

在线全文

学校读者我要写书评

暂无评论

Science in China(Series F) 2009年第1期52卷 91-99页

作者： ZHANG Lei JING Wei XING MengDao BAO Zheng Key laboratory for radar signal processing Xidian University Xi'an 710071 China

A new approach for unparallel trajectory bistatic spotlight SAR imaging is proposed. The approach utilizes the concept of instantaneous Doppler wavenumber and introduces two variants, the sum-range and subtraction-range, to develop the 2D frequency analytical formula. Based on the assumption of plane wavefront, the transmitting and receiving Doppler are separated and formulated via series reversion. And frequency scaling is applied to focus image. The algorithm is with high computational efficiency, and provides well focus for limited scene imaging. Simulation result confirms the validity of the approach.

关键词： unparallel trajectory bistatic SAR instantaneous Doppler wavenumber series reversion frequency scaling algorithm unparallel trajectory bistatic SAR instantaneous Doppler wavenumber series reversion frequency scaling algorithm