共查询到20条相似文献,搜索用时 10 毫秒
1.
Chen Sun Hirata A. Ohira T. Karmakar N.C. 《Antennas and Propagation, IEEE Transactions on》2004,52(7):1819-1832
A low-power consumption, small-size smart antenna, named electronically steerable parasitic array radiator (ESPAR), has been designed. Beamforming is achieved by tuning the load reactances at parasitic elements surrounding the active central element. A fast beamforming algorithm based on simultaneous perturbation stochastic approximation with a maximum cross correlation coefficient criterion is proposed. The simulation and experimental results validate the algorithm. In an environment where the signal-to-interference-ratio is 0 dB, the algorithm converges within 50 iterations and achieves an output signal-to-interference-plus-noise-ratio of 10 dB. With the fast beamforming ability and its low-power consumption attribute, the ESPAR antenna makes the mass deployment of smart antenna technologies practical. 相似文献
2.
Electronically steerable passive array radiator (ESPAR) antennas are considered to have the capability to form a beam spatially toward the desired signal with the lowest cost. We propose a method to realize space-time adaptive filtering (STAF) by employing ESPAR antennas for TDMA or CDMA signal waveforms. According to the method, the cochannel interference signals are spatially suppressed by the adaptive beamforming, and the intersymbol interference signals are suppressed by the temporal waveform-based adaptive equalization. Simulation results show the effectiveness of the proposed method in the signal environment of a local network communication system. 相似文献
3.
A novel ground-plane shape to improve the horizontal gain for electrically steerable passive array radiator (ESPAR) antennas is investigated. The peak directivity of a monopole antenna with a finite ground plane, such as a circular or rectangular ground plane is at a higher angle from the horizon. Thus, the horizontal gain is lower than that of a dipole antenna. Using a circular ground plane of a half-wavelength radius with a skirt of a quarter wavelength wound around it, the angle of the peak directivity and the horizontal gain for the ground-based communication system were improved. For an ESPAR antenna - one of the monopole arrays - the horizontal gain was also improved. It was confirmed that it was possible to form the main-beam radiation and a beam in the horizontal plane, each in an arbitrary direction, by changing the control voltage to the passive element. This was shown by an experiment with an ESPAR antenna with a finite reflector, a feed element, and seven passive elements. 相似文献
4.
5.
6.
7.
Sparse linear arrays provide better performance than the filled linear arrays in terms of direction estimation and resolution with reduced size and low cost. However, they are subject to manifold ambiguity. A method based on the Multiple Signal Classification (MUSIC) algorithm to solve the manifold ambiguity of uncorrelated sources for sparse array is proposed in this paper. The method consists of two steps. The first step is to obtain all the directions of arrivals (DOAs), including true and spurious DOAs, using traditional MUSIC. The second step is to estimate the power values of the all DOAs by substituting all the DOAs to a cost function. The well-known Davidson Fletcher Powell (DFP) and Broyden Fletcher Goldfarb Shanno (BFGS) algorithms are used to estimate the power values. The power values of spurious DOAs are very small or tend to zero compared with the values of the true DOAs. The true DOAs are then discriminated easily from the spurious DOAs with the power values. Simulation results demonstrate the effectiveness and the feasibility of the method. 相似文献
8.
《Electronics letters》2005,41(16):47-48
9.
The multiple signal classification (MUSIC) algorithm has been considered to be the most effective for direction-of-arrival estimation. However, MUSIC requires considerable computation. To reduce this computational load to the extent that the sensor array system may follow rapid changes in the radio environment. The author proposes the smart MUSIC (SMUSIC) algorithm. In SMUSIC, the only requirements are the calculation of a few basis vectors and calculation of just one vector orthogonal to basis vectors. The superior characteristics of SMUSIC's reduced processing time and high resolution are simulated numerically 相似文献
10.
The authors believe that special-purpose architectures for digital signal processing (DSP) real-time applications will use closely coupled processing elements as array processor modules to implement the various portions of the new algorithms, and several such modules will cooperate in a pipelined manner to implement complete algorithms. Such an architecture, based upon systolic modules, for the MUSIC algorithm is presented. The architecture is suitable for VLSI implementation. The throughput of the pipelined approach is O (N ), whereas the sequential approach is O (N 3) 相似文献
11.
针对目前多信号环境中信号的测频测向问题,利用非均匀时延,解开频率和信号到达角之间存在的耦合,在此基础上实现了解耦合的二维MUSIC算法。可同时测量信号频率和到达角,计算量小,并保持了MUSIC算法测量精度高的特点。仿真结果证明了该方法的有效性。 相似文献
12.
Zhang Xiaofei Zhou Ming Chen Han Li Jianfeng 《Multidimensional Systems and Signal Processing》2014,25(3):583-600
This paper discusses the problem of two-dimensional (2D) direction of arrival (DOA) estimation for acoustic vector-sensor array, and derives a successive multiple signal classification (MUSIC) algorithm therein. The proposed algorithm obtains initial estimations of the azimuth and elevation angles obtained from the signal subspace, and uses successively one-dimensional local searches to achieve the joint estimation of 2D-DOA. The proposed algorithm, which requires the one-dimension local searches, can avoid the high computational cost within 2D-MUSIC algorithm. The proposed algorithm can obtain automatically-paired 2D-DOA estimation for acoustic vector-sensor array, and it has better DOA estimation performance than propagator method, estimation of signal parameters via rotational invariance technique algorithm and trilinear decomposition algorithm. Meanwhile, it has very close angle estimation to 2D-MUSIC algorithm. Furthermore, it is suitable for non-uniform linear arrays, works well for the sources with the same azimuth angle, and imposes less constraint on the sensor spacing, which does not have to be restricted within half-wavelength. We have also derived the mean-square error of DOA estimation of the proposed algorithm and the Cramer-Rao bound of DOA estimation. Simulation results verify the usefulness of the proposed algorithm. 相似文献
13.
Xiaofei Zhang Chen Chen Jianfeng Li Dazhuan Xu 《Multidimensional Systems and Signal Processing》2014,25(1):67-82
A novel blind direction-of-arrival (DOA) and polarization estimation algorithm for polarization-sensitive uniform linear array using dimension reduction multiple signal classification (MUSIC) is proposed in this paper. The proposed algorithm utilizes the signal subspace to obtain an initial estimation of DOA, then estimates more accurate DOA through a one-dimensional (1-D) local searching according to the initial estimation of DOA, and finally obtains polarization parameter estimation via the estimated polarization steering vectors. The proposed algorithm, which only requires a one-dimension local searching, can avoid the high computational cost within multi-dimensional MUSIC algorithm. The simulation results reveal that the proposed algorithm has better DOA and polarization estimation performance than both estimation of signal parameters via rotational invariance technique algorithm and trilinear decomposition algorithm. Furthermore, the proposed algorithm can be suitable for irregular array geometry, obtain automatically paired multi-dimensional parameter estimation, and avoid multi-dimensional searching. Simulation results verify the effectiveness of the proposed algorithm. 相似文献
14.
Simulation results for a dual-band switched parasitic smart antenna array designed for cellular communications systems are presented. The array consists of six loaded monopole elements on an infinite ground plane and offers five switched directions equally spaced through 360°. At 900 and 1900 MHz, the 10 dB bandwidths are 15 and 13%, respectively. The antenna covers the azimuth plane with a maximum gain of 4 dBi and a minimum gain of 2 dBi. The front-to-back ratios of the radiation patterns are better than -15 dB. The design is robust in terms of manufacturing and environmental tolerances 相似文献
15.
This paper proposes low-cost yet high-accuracy direction of arrival (DOA) estimation for the automotive frequency-modulated continuous-wave (FMCW) radar. The existing subspace-based DOA estimation algorithms suffer from either high computational costs or low accuracy. We aim to solve such contradictory relation between complexity and accuracy by using randomized matrix approximation. Specifically, we apply an easily-interpretable randomized low-rank approximation to the covariance matrix (CM) and approximately compute its subspaces. That is, we first approximate CM \begin{document}${\bf{R} }\in {\mathbb{C}}^{M\times M} $\end{document} ![]()
![]()
through three sketch matrices, in the form of \begin{document}$\mathbf{R}\approx \mathbf{Q}\mathbf{B}{\mathbf{Q}}^{\mathrm{H}} $\end{document} ![]()
![]()
. Here the matrix \begin{document}$\mathbf{Q}\in {\mathbb{C}}^{M\times z} $\end{document} ![]()
![]()
contains the orthonormal basis for the range of the sketch matrix \begin{document}$\mathbf{C}\in {\mathbb{C}}^{M\times z} $\end{document} ![]()
![]()
which is extracted from \begin{document}$ \mathbf{R} $\end{document} ![]()
![]()
using randomized uniform column sampling and \begin{document}$ \mathbf{B}\in {\mathbb{C}}^{z\times z} $\end{document} ![]()
![]()
is a weight-matrix reducing the approximation error. Relying on such approximation, we are able to accelerate the subspace computation by the orders of the magnitude without compromising estimation accuracy. Furthermore, we drive a theoretical error bound for the suggested scheme to ensure the accuracy of the approximation. As validated by the simulation results, the DOA estimation accuracy of the proposed algorithm, efficient multiple signal classification (E-MUSIC), is high, closely tracks standard MUSIC, and outperforms the well-known algorithms with tremendously reduced time complexity. Thus, the devised method can realize high-resolution real-time target detection in the emerging multiple input and multiple output (MIMO) automotive radar systems. 相似文献
16.
A mathematical summary of the joint complex least squares lattice (JCLSL) adaptive algorithm is presented. The algorithm has as inputs two scalar discrete time series (primary. and reference channels). Output consists of the filtered reference channel subtracted from the primary channel. The convergence characteristics of the algorithm are illustrated experimentally for a problem where the reference channel time series consists of dual constant frequency sinusoids which undergo an instantaneous step in frequency. The primary channel time series consists of dual constant frequency sinusoids whose frequencies coincide with those of the reference channel after the step. Lastly, an application of the JCLSL algorithm to the rejection of ocean acoustic boundary reverberation is described. 相似文献
17.
A ten-element array of log-periodic monopole antennas with a power gain of about 20 dB is described. The individual elements are designed for input continuous wave (or peak) powers of 200 kW and differ somewhat from previous monopole configurations. The array element spacing is adjusted so that when it is electronically scanned in synchronism with the associated receiving array all side and grating lobes of the two-way pattern are down at least 20 dB. Element, array, and ground screen designs are discussed, as well as the model array mutual coupling measurements, electronic scanning systems and the associated coaxial transmission lines. 相似文献
18.
R. Ghayoula A. Smida A. Gharsallah D. Grenier 《International Journal of Communication Systems》2014,27(12):3706-3719
This paper presents practical design of a smart antenna system based on direction‐of‐arrival estimation and Dolph–Chebyshev beam forming. Direction‐of‐arrival estimation is based on the multiple signal classification algorithm for identifying the directions of the source signals incident on the sensor array comprising the smart antenna system. The smart antenna system design involves a hardware part, which provides real data measurements of the incident signals received by the sensor array. This paper presents the Dolph–Chebyshev method for the synthesis and design of antenna arrays with periodic element spacing. A Field‐Programmable Gate Array implementation is presented for an antenna array application employing digital beamforming. The array comprises 10 elements, equal in number receiving radio frequency and intermediate frequency components, as well as a Spartan‐3E Field‐Programmable Gate Array‐based unit, which is responsible for the control of the array. Low‐cost and switched‐beam, and fully adaptive antenna array suitable for 2‐GHz applications are proposed in this paper. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
19.
20.
MUSIC算法是一种空间谱估计算法,在对宽带信号进行空间谱估计时,该算法需要较长的观测时间来估计协方差矩阵,不利于高速运动目标的定位。提出了基于驾驶协方差矩阵(STCM)的MUSIC算法,该算法首先对每个频带的CSDM进行特征分解,然后利用各频带的噪声子空间求得噪声空间的STCM,进而利用噪声空间的STCM直接得到整个宽带信号的空间谱估计结果。仿真表明该算法在保证高分辨率的同时,需要较短观测时间,适用于较低信噪比、具有较小观测方差。 相似文献