共查询到20条相似文献,搜索用时 328 毫秒
1.
针对强干扰背景下的弱目标被动探测与定位问题,提出了一种基于特征分解的稳健波束形成方法。首先搭建了一个由信号子空间与干扰方向导向矢量组合的特殊矩阵,理论推导了该矩阵特征向量与信号导向矢量间的内在关系,并证明这种数学关系仅与信号间相对方位有关,与信号能量无关;接着利用该关系,构造了能够抑制训练数据中期望信号并保证其余信号功率不变的预处理矩阵;最后对预处理后的训练数据,结合对角加载方法,获得最终波束形成方法的权向量。仿真实验证明,在干扰区间已知时,该算法在保证波束形成的稳健性同时,具有更强的干扰抑制能力。 相似文献
2.
常规的自适应数字波束形成方法仅限于利用信号的二阶统计特性,当其工作在相干干扰环境中时,由于接收信号协方差矩阵的信号子空间的一些向量收敛到噪声空间中,此时二阶统计量方法无法准确提取干扰方位信息,从而导致该波束形成器很难取得较好的抗干扰性能.因为高阶累计量能包含更多的统计信息,运用高阶累计量方法来提取干扰信号方位信息,然后根据最小均方误差准则来形成波束图,试验表明基于高阶累计量的自适应波束形成方法能够较为有效地抑制相干干扰源,并且该方法减少了对阵列流型的依赖,具有较好的容差性。 相似文献
3.
4.
本文在Maximin波束形成方法的基础上,提出了一种正交多干扰子空间矩阵对方法。本方法可有效分离同信道多窄带干扰信号,同时利用期望信号与干扰信号到达方向不同,对自相关矩阵对进行广义特征值分解实现干扰背景下PN码序列的同步和波束形成。在信号同步上,无需导频信道信息和训练序列信息;在同步过程中得到的与主广义特征值相应的特征向量可以直接作为波束形成器的权向量,进行后续的波束形成。仿真比较实验结果证明,所提方法可以抵抗与期望信号不同方向的窄带强干扰,尤其在强多用户干扰和强窄带干扰背景下,与PAPC(pre and post correlation)方法和FP(filter pair)方法相比具有明显的性能优势。 相似文献
5.
雷达辐射源信号模糊函数主脊切面特征提取方法 总被引:11,自引:1,他引:10
提取和补充新的信号参数是解决复杂体制雷达辐射源信号分选难题的有效手段.基于模糊函数在表征信号内在结构上的独特作用,本文提出一种模糊函数主脊切面特征提取的新方法,构建出由主脊方向、切面重心和惯性半径组成的主脊切面特征向量.理论分析和实验结果表明,所提取的特征向量较好地反映了不同信号波形结构上的差异,具有类内聚敛性强和类间分离度大的优点,且具备较好的抗噪性能,证实了所提方法的可行性和有效性. 相似文献
6.
介绍了自适应波束形成技术的基本原理, 对具体算法进行了数学推导。根据波束形成技术的特点, 提出一种将其应用于GNSS抗干扰系统的解决方案。以七阵元均匀圆阵为例, 推导出期望信号的阵列响应公式, 给出接收信号协方差矩阵的求解方法, 从而为将自适应波束形成技术应用于GNSS抗干扰系统铺平了道路。仿真显示利用该方法能够在卫星信号来向保持一定增益的同时, 在干扰来向形成深度零陷, 从而达到较好的GNSS抗干扰效果。 相似文献
7.
8.
本文研究在通用计算机上模拟一个长线阵被动声纳站现场试验的有关问题。模拟研究的实施方法是:计算机首先产生一组能够反映目标信号特性以及目标在水平面内逐点转动的数字信号;然后按照“频率域上合成波束”原理所规定的信号处理顺序,计算机进行各步运算,得到声纳站的各个搜索波束在-90°到 90°目标方位范围内的输出响应,由此可以估计声纳站的实际检测性能及检验声纳站的预定设计方案。本文分析和比较了“FFT-DFT”和“FFT-FFT”两种多波束设计方案的模拟处理结果,从而表明“频率域上合成波束”的信号处理方案能够成功地用于构成长线阵的多波束检测系统;并且也对有关理论分析所预示的结果作了验证。 相似文献
9.
10.
常规的自适应数字波束形成方法仅限于利用信号的二阶统计特性,当其工作在相干干扰环境中时,由于接收信号协方差矩阵的信号子空间的一些向量收敛到噪声空间中,此时二阶统计量方法无法准确提取干扰方位信息,从而导致该波束形成器很难取得较好的抗干扰性能。因为高阶累计量能包含更多的统计信息,运用高阶累计量方法来提取干扰信号方位信息,然后根据最小均方误差准则来形成波束图,试验表明基于高阶累计量的自适应波束形成方法能够较为有效地抑制相干干扰源,并且该方法减少了对阵列流型的依赖,具有较好的容差性。 相似文献
11.
12.
针对传统自适应波束形成算法中目标波达方向(Direction of Arrival,DOA)估计不准确引起的波束形成性能下降问题,提出了一种采用投影对消矩阵的稳健自适应波束形成算法.首先,寻找与估计波达方向有最大相关性的特征矢量作为目标信号特征矢量,然后构建对消矩阵消除协方差矩阵中的信号分量,最后通过增加零点约束实现干扰抑制.与传统对角加载类稳健波束形成算法相比,所提算法不受对角加载因子的影响,且在信干噪比较大时仍然具有良好的抗干扰性能.仿真对比实验验证了所提算法的有效性. 相似文献
13.
A novel adaptive beamforming algorithm for antenna array CDMA systems with strong interferers 总被引:12,自引:0,他引:12
Seungwon Choi Jinho Choi Heung-Jae Im Byungcho Choi 《Vehicular Technology, IEEE Transactions on》2002,51(5):808-816
Blind beamforming based on the maximum signal-to-noise ratio (MSNR) can improve the performance of an array system only when the processing gain of the given code-division multiple-access (CDMA) system is high enough such that the desired signal can become dominant after despreading (see Choi, S. and Shim, D., IEEE Trans. Veh. Technol., vol.49, p.1793-1806, 2000; Choi, S. and Yun, D., IEEE Trans. Antennas Propagat., vol.45, p.1393-1404, 1997). We consider a maximum signal-to-interference-plus-noise ratio (MSINR) beamforming. The MSINR performance criterion is chosen to deal with strong interferers effectively. It is shown that blind MSINR beamforming is possible by directly utilizing the input and output signals of correlators of the CDMA systems. In addition, we propose an adaptive beamforming algorithm at a lower computational complexity - about O(7.5N) - where N is the number of antenna elements of the array system. Simulation results are presented in various signal environments to show the performance of the proposed adaptive algorithm. 相似文献
14.
15.
针对DS-CDMA系统,在基于特征空间(ESB)自适应波束形成算法的基础上提出了一种基于最大特征值的改进算法,该算法利用阵列接收信号协方差矩阵最大特征值所对应的特征向量构成子空间,摈弃了权向量在干扰信号子空间及噪声子空间中的分量.改进算法结构简单、运算量低.计算机仿真和分析证明该算法性能要优于常规ESB算法的性能. 相似文献
16.
This paper deals with the problem of robust adaptive array beamforming using signal cyclostationarity. The constrained cyclic adaptive beamforming (C-CAB) algorithm presented by Wu and Wong (1996) [6] has been shown to be effective in performing adaptive beamforming without requiring the direction vector or the waveform of the desired signal. However, this algorithm suffers from severe performance degradation even if there is a small mismatch in the cycle frequency of the desired signal. In this paper, we first evaluate the performance degradation of the C-CAB algorithm in the presence of cycle frequency error (CFE). A novel compensation method in conjunction with the subspace projection is then proposed to tackle the problem due to CFE. We reconstruct the required cyclic conjugate correlation matrix by using a compensation matrix to cope with the deterioration of its dominant singular value when CFE exists. Finally, several simulation examples are provided to show the effectiveness of the proposed algorithm. 相似文献
17.
One of the main benefits of the cyclostationary beamforming algorithms is their ability to extract signals from co-channel
interference with only a knowledge of the cycle frequency. In this paper, we study the popular cyclostationary beamformers,
and propose five new algorithms, namely, the adaptive cyclic adaptive beamforming (ACAB), adaptive cross-SCORE (ACS), constrained
least-squares (CLS), adaptive phase-SCORE (APS), and maximal constrained autocorrelation (MCA) algorithms. All these algorithms
are adaptive and have a computational complexity of O(n
2) complex multiplications, where n is the number of array elements. A comparative study of these algorithms is made based on numerical simulations. Each of
these algorithms has specific application scenarios. The ACS and the APS algorithms are particularly suited for very adverse
signal environments. The ACAB, MCA and cyclic adaptive beamforming (CAB, from the work of Wu and Wong) algorithms can provide
good performance in the case of medium or weak interference, while the CLS algorithm is especially suitable for weak interference.
The CAB algorithm is shown to be a special case of the least-square self-coherent restoral (LS-SCORE) algorithm. Some insights
as to how one can assign carrier frequency and symbol rate during digital modulation are also suggested. The proposed adaptive
algorithms are easy to implement, and thus are very promising for applications in wireless and mobile communications.
This work was supported by the NSERC of Canada. 相似文献
18.
针对于CDMA系统自适应天线阵列,提出了一种新的盲自适应MSINR(Maximum Signal-to-Interference plus noise ratio)波束形成算法.首先,将MSINR准则转化为一种新的无约束损失函数,并且从理论上分析该损失函数的性质.然后,应用自适应拟牛顿方法得到在线迭代波束形成算法.该算法无需训练序,而是利用CDMA信号自身的结构特点,结合空间处理提高了系统性能.最后,给出了仿真结果,表明算法具有较快的收敛速度和良好的动态跟踪能力. 相似文献
19.
We introduce the new adaptive beamforming algorithm which improves the performance of an adaptive antenna array system through a forward/backward averaging scheme of the post-correlation signal vector and a signal enhancement scheme using Hermitian Toeplitzation of an array covariance matrix in DS/CDMA. A forward/backward averaging scheme decorrelates the received correlated signal after despreading in a matched filter and the Hermitian Toeplitzation scheme enhances the performance of the received signal by removing the undesired effect obtained from an array covariance matrix estimation. It is shown through simulation results that the performance of the proposed algorithm is very superior to that of the conventional Wiener maximal ratio combining (MRC) algorithm 相似文献