共查询到20条相似文献,搜索用时 46 毫秒
1.
A Method for the Direction-of-Arrival Estimation of Incoherently Distributed Sources 总被引:3,自引:0,他引:3
《Vehicular Technology, IEEE Transactions on》2008,57(5):2885-2893
2.
Du Jiang Song Ting Zheng Yuzheng Taekon Kim 《电子科学学刊(英文版)》2008,25(1):134-139
In wireless communication environment, the time-varying channel and angular spreads caused by multipath fading and the mobility of Mobile Stations (MS) degrade the performance of the conventional Direction-Of-Arrival (DOA) tracking algorithms. On the other hand, although the DOA estimation methods based on the Maximum Likelihood (ML) principle have higher resolution than the beamforming and the subspace based methods, prohibitively heavy computation limits their practical applications. This letter first proposes a new suboptimal DOA estimation algorithm that combines the advantages of the lower complexity of subspace algorithm and the high accuracy of ML based algorithms, and then proposes a Kalman filtering based tracking algorithm to model the dynamic property of directional changes for mobile terminals in such a way that the association between the estimates made at different time points is maintained. At each stage during tracking process, the current suboptimal estimates of DOA are treated as meas urements, predicted and updated via a Kalman state equation, hence adaptive tracking of moving MS can be carried out without the need to perform unduly heavy computations. Computer simulation results show that this proposed algorithm has better performance of DOA estimation and tracking of MS than the conventional ML or subspace based algorithms in terms of accuracy and robustness. 相似文献
3.
Maximum likelihood direction-of-arrival estimation in unknown noise fields using sparse sensor arrays 总被引:2,自引:0,他引:2
We address the problem of maximum likelihood (ML) direction-of-arrival (DOA) estimation in unknown spatially correlated noise fields using sparse sensor arrays composed of multiple widely separated subarrays. In such arrays, intersubarray spacings are substantially larger than the signal wavelength, and therefore, sensor noises can be assumed to be uncorrelated between different subarrays. This leads to a block-diagonal structure of the noise covariance matrix which enables a substantial reduction of the number of nuisance noise parameters and ensures the identifiability of the underlying DOA estimation problem. A new deterministic ML DOA estimator is derived for this class of sparse sensor arrays. The proposed approach concentrates the ML estimation problem with respect to all nuisance parameters. In contrast to the analytic concentration used in conventional ML techniques, the implementation of the proposed estimator is based on an iterative procedure, which includes a stepwise concentration of the log-likelihood (LL) function. The proposed algorithm is shown to have a straightforward extension to the case of uncalibrated arrays with unknown sensor gains and phases. It is free of any further structural constraints or parametric model restrictions that are usually imposed on the noise covariance matrix and received signals in most existing ML-based approaches to DOA estimation in spatially correlated noise. 相似文献
4.
针对传统光谱搜索方法的搜索复杂度和估计精度严格依赖于搜索过程中所用搜索网格数而导致搜索耗时较多的问题,提出了一种基于改进粒子群优化(PSO)的信号到达方向(DOA)估计方法。首先分析了硬约束PSO最小方差无失真响应(MVDR)估计器(HPSO-MVDR);然后针对HPSO-MVDR估计器的不足,提出了一种粒子搜索位置映射技术;最后提出了基于改进PSO MVDR(MPSO-MVDR)估计器。实验结果表明,在角度搜索中结合改进粒子群算法,提出的方法明显降低了搜索复杂度,相比现有光谱搜索方法的估计更加精确。 相似文献
5.
Application of natural computing algorithms to maximum likelihood estimation of direction of arrival 总被引:1,自引:0,他引:1
This work presents a study of the performance of populational meta-heuristics belonging to the field of natural computing when applied to the problem of direction of arrival (DOA) estimation, as well as an overview of the literature about the use of such techniques in this problem. These heuristics offer a promising alternative to the conventional approaches in DOA estimation, as they search for the global optima of the maximum likelihood (ML) function in a framework characterized by an elegant balance between global exploration and local improvement, which are interesting features in the context of multimodal optimization, to which the ML-DOA estimation problem belongs. Thus, we shall analyze whether these algorithms are capable of implementing the ML estimator, i.e., finding the global optima of the ML function. In this work, we selected three representative natural computing algorithms to perform DOA estimation: differential evolution, clonal selection algorithm, and the particle swarm. Simulation results involving different scenarios confirm that these methods can reach the performance of the ML estimator, regardless of the number of sources and/or their nature. Moreover, the number of points evaluated by such methods is quite inferior to that associated with a grid search, which gives support to their application. 相似文献
6.
针对期望信号波达角(DOA)估计误差较大时相干波束形成性能下降的问题,该文提出一种基于多级阻塞的稳健相干自适应波束形成算法。该算法首先定义阻塞矩阵,推导多级阻塞原理,并利用其滤除阵列接收信号中的期望信号;然后给出空间中只存在期望信号时,子阵与全阵间阵列流型的映射关系,据此推导全阵扩展变换,并证明其在干扰信号存在条件下的有效性;最终利用扩展变换获取全阵最优权矢量,实现相干波束形成。该算法对期望信号波达角估计误差稳健,且无需干扰信号来向的先验信息,同时可以有效避免阵列孔径的损失。仿真分析验证了算法的优越性和理论分析的有效性。 相似文献
7.
基于最大似然估计(ML)的阵列测向方法具有测向精度高、可以分辨相干信号等优点,但是因为计算复杂度过高而工程应用受限。针对该问题,利用交叉熵(CE)方法对最大似然估计快速求解,并对初始样本的产生和平滑参数的设置进行了优化,提出改进型CE—ML二维测向算法,最后进行了算法运算量分析和仿真验证。仿真实验表明,在精度相近条件下,改进型的CE-ML算法的迭代次数大约是粒子群算法(Ps0)的1/3,大大减少了ML测向的计算量。 相似文献
8.
为有效接收多径相干信号,该文提出一种基于波束主瓣幅度约束的鲁棒自适应波束形成算法。该算法充分利用多径相干信号的来波信息,对接收数据协方差矩阵统计量进行优化,并对多径相干信号波束主瓣进行幅度约束,通过一阶泰勒展开将多径相干信号的优化问题转换为迭代二阶锥规划问题,获得最佳波束形成权矢量。该算法不仅能够有效接收多径相干信号,抑制干扰和噪声,而且能够克服较大导向矢量失配误差,自由控制鲁棒响应区的波束宽度和纹波水平。仿真实验验证了算法的正确性和有效性。 相似文献
9.
Fast DOA estimation algorithm using pseudocovariance matrix 总被引:1,自引:0,他引:1
Jung-Tae Kim Sung-Hoon Moon Dong Seog Han Myeong-Je Cho 《Antennas and Propagation, IEEE Transactions on》2005,53(4):1346-1351
This paper proposes a new direction of arrival (DOA) estimation algorithm that can rapidly estimate the DOAs of incidence signals using a pseudocovariance matrix even under coherent interference environments. The conventional multiple signal classification (MUSIC) algorithm, which should estimate a covariance matrix, cannot perform a DOA estimation until it acquires the covariance matrix. In addition, the MUSIC algorithm cannot be used under rapidly changing or correlated interference environments. In contrast, the proposed algorithm can obtain a bearing response after acquiring the pseudocovariance matrix based on a single snapshot. Signal incidence angles can then be accurately estimated by combining the bearing response and the location of pattern s. Accordingly, the proposed algorithm can rapidly estimate the DOAs of signals even when they are correlated. 相似文献
10.
Blind adaptive beamforming for cyclostationary signals 总被引:7,自引:0,他引:7
Qiang Wu Kon Max Wong 《Signal Processing, IEEE Transactions on》1996,44(11):2757-2767
In order to increase the capacity and to suppress co-channel interference in digital communication systems such as mobile cellular and mobile satellite communication systems, the employment of array beamforming techniques has been proposed. However, conventional beamforming methods are not suitable for such cases since these methods were mainly developed for signal detection and direction-of-arrival (DOA) estimation in radar and sonar. In this paper, utilizing the cyclostationary properties of communication signals, we propose three blind cyclic adaptive beamforming (CAB) algorithms and their fast implementation schemes. Several numerical examples are included. These results demonstrate that the CAB algorithms are good candidates for spatial reuse of frequency spectrum in digital mobile communication systems of the next generation 相似文献
11.
提出了在基于来波方向估计和自适应波束成形的相控阵天线系统中,用多重信号分类(MUSIC)算法实现来波方向估计,并使用线性约束最小方差(LCMV)的自适应算法控制天线的主瓣方向,实现对期望信号的跟踪,同时实现对干扰信号的零陷处理。仿真结果表明,MUSIC算法可以有效识别相控阵天线接收端的信号的入射方向,LCMV算法可以实现对有用信号的自适应跟踪和对干扰信号的抑制。 相似文献
12.
13.
Stoica P. Ottersten B. Viberg M. Moses R.L. 《Signal Processing, IEEE Transactions on》1996,44(1):96-105
Maximum likelihood (ML) estimation in array signal processing for the stochastic noncoherent signal case is well documented in the literature. We focus on the equally relevant case of stochastic coherent signals. Explicit large-sample realizations are derived for the ML estimates of the noise power and the (singular) signal covariance matrix. The asymptotic properties of the estimates are examined, and some numerical examples are provided. In addition, we show the surprising fact that the ML estimates of the signal parameters obtained by ignoring the information that the sources are coherent coincide in large samples with the ML estimates obtained by exploiting the coherent source information. Thus, the ML signal parameter estimator derived for the noncoherent case (or its large-sample realizations) asymptotically achieves the lowest possible estimation error variance (corresponding to the coherent Cramer-Rao bound) 相似文献
14.
Wen-Hsien Fang Chia-Chien Tu Yie-Tarng Chen 《Multidimensional Systems and Signal Processing》2018,29(2):783-798
This paper presents two nested algorithms—one based on the Estimation of Signal Parameters via Rotational Invariance Technique (ESPRIT) algorithm and the other one on the maximum likelihood estimation—for joint direction of departure (DOD) and direction of arrival (DOA) estimation in bistatic multiple-input multiple-output radar. Both of the proposed nested algorithms interweaves signal grouping schemes and DOD/DOA estimation. Thereby, in each stage only DODs or DOAs, but not both, need to be estimated, and thus the complexity called for can be reduced. Also, the signals in each group have close DOAs, yet diverse DODs, and vice versa, so both DODs and DOAs can be precisely estimated even some of them are very close. Additionally, the estimated DODs and DOAs are automatically paired together without extra computations. Also, for the proposed nested-ML, a non-iterative importance sampling-based ML estimator is developed which is ensured to attain global optimum. Simulation results show that the proposed nested-ESPRIT can provide competing performance, yet with much lower complexity compared with the main state-of-the-art works; whereas, nested-ML can reach the Cramer–Rao lower bound with slightly higher complexity. 相似文献
15.
提出了一种相干宽带线性调频(LFM)信号的波达方向(DOA)估计新方法。该方法利用LFM信号在分数阶Fourier域上的解线调特性,构造出新的解线调域阵列数据模型,然后结合传统的矩阵重构解相干以及MUSIC算法实现相干LFM信号的DOA估计。若同时存在多组相干LFM信号入射,则首先在不同的能量聚集域上将各信号组分离,然后逐一进行各组内相干信号的DOA估计。该方法充分地挖掘了观测信号所包含的时频信息,增加了可检测的DOA数目,提高了分辨性能和抗噪声性能。此外,该方法无冗余阵元与孔径损失,且适用于任意流型阵列。仿真结果显示,在DOA估计的均方根误差(RMSE)相同时,与传统方法相比,本方法可获得8dB左右的信噪比增益。 相似文献
16.
A new direction-of-arrival (DOA) estimation method for coherent global positioning system (GPS) signals is proposed. It is applicable to the GPS propagation environment with rich multipath, strong interferences and noise. According to the properties of oblique projection, interferences and noise are first suppressed and only the coherent GPS signals are retained by projecting the received signal onto the signal subspace. Then, the coherent GPS signals are resolved by the Toeplitz decorrelation scheme. Using the proposed method, interferences and noise can be suppressed simultaneously, and more accurate DOA estimation for coherent GPS signals can be obtained in GPS propagation environment. Simulation results demonstrate the effectiveness of the proposed method. 相似文献
17.
《IEEE transactions on circuits and systems. I, Regular papers》2008,55(10):3077-3089
18.
Multiple emitter location and signal parameter estimation 总被引:161,自引:0,他引:161
19.
Shiann‐Shiun Jeng Hsin‐Piao Lin Chen‐Wan Tsung 《International Journal of Communication Systems》2003,16(3):211-223
This paper presents some preliminary results from experimental studies on space‐division‐multiple‐access (SDMA) for wireless communications. A smart antenna system utilizing direction‐of‐arrival (DOA)‐based beamforming techniques can enhance signal quality by reducing co‐channel interference from mobiles located at angles spatially distinct from the base station. Adopting both smart uplink and downlink beamforming, a communication system with an antenna array can increase the cell coverage of a base station and significantly boost capacity compared with conventional antenna systems. However, successful implementation of DOA‐based beamforming techniques depends on the DOA characteristics. This paper presented the feasibility of direction finding and DOA variation with respect to frequency. Furthermore, the angle spread was studied for selected environments. The results demonstrate the feasibility of applying proposed smart antenna system utilizing DOA‐based beamforming algorithm for increasing channel capacity and improving system performance in frequency‐division‐duplex (FDD) wireless communication systems. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
20.
《Signal Processing, IEEE Transactions on》2009,57(9):3523-3532