部分极化干扰条件下极化阵列性能分析

研究部分极化干扰条件下极化阵列的滤波抗干扰性能,期望信号为完全极化波,干扰信号为部分极化波.利用最大信噪比准则得到阵列最大输出信号干扰噪声比(SINR)的解析表达式,分析干扰极化度,到达角等因素对阵列抗干扰性能的影响,仿真实验验证理论分析的正确性.     

通道失配对极化敏感阵列滤波性能的影响

在极化敏感阵列通道失配条件下,建立了极化敏感阵列接收信号误差模型。把通道失配误差分解为阵元极化信息误差和阵列孔径信息误差,给出误差量明确物理解释。在单干扰源情况下,分析了通道失配对极化敏感阵列滤波性能的影响,并给出通道失配条件下,期望信号和干扰信号间的空间匹配系数、极化匹配系数和最大SINR表达式,最后,通过计算机仿真验证了文中结果,并给出有意义的结论。     

阵列互耦对极化敏感阵列滤波性能的影响

在阵列互耦条件下,给出了极化敏感阵列接收信号模型;并在形式上把互耦误差分解为正交阵元接收因子误差和阵列接收因子误差,分别代表了阵列接收信号极化信息误差和空间信息误差.给出互耦条件下,信号、干扰空间匹配系数、极化匹配系数和最大SINR的数学表达式.在单干扰源情况下,分析了阵列互耦对极化敏感阵列滤波性能的影响.     

极化敏感阵列斜投影滤波性能分析

该文研究了极化敏感阵列采用斜投影滤波和正交投影滤波的输出信干噪比(SINR)特性。推导获得了斜投影滤波与正交投影滤波在理想情况和存在阵列误差时的输出SINR 计算式:理想情况下输出SINR 是信噪比(SNR)、目标与干扰的空域和极化域匹配系数的函数;存在阵列误差情况时输出SINR 受信噪比,干噪比(INR)、目标与干扰的空域-极化域匹配系数及误差扰动量共同影响。分析表明,相比正交投影滤波而言,斜投影滤波的输出SINR没有改善,也不能提高误差稳健性,它们均低于最优输出SINR;正交投影与斜投影输出SINR 相同的成因并不一样,正交投影滤波改变了目标的幅相特性,滤波后目标有损失;斜投影滤波改变了输出噪声的空域-极化域特性,放大了输出噪声的功率。最后通过仿真实验验证了理论分析的正确性。      

极化阵列抗主瓣干扰性能研究

为改善极化敏感阵列主瓣抗干扰性能,分析了基于特征空间投影算法的交替极化敏感阵列的主瓣干扰抑制性能,并与常规极化敏感阵列进行了比较.讨论了期望信号和干扰信号的空域和极化域匹配系数对阵列输出信干噪比的影响;分析了在期望信号导向矢量失配情况下,采用特征空间投影算法改善两种极化敏感阵列的主瓣抗干扰性能.理论分析和仿真结果表明:在期望信号导向矢量存在误差情况下,基于特征空问投影算法的交替极化敏感阵列具有良好的稳健性.交替极化敏感阵列系统复杂度低、更易于工程实现.     

强干扰环境中SINR极化滤波器的性能分析

研究了最优极化滤波问题,针对已有工作对信号干扰噪声比(SINR)极化滤波器性能分析的不完备性,对强干扰环境中SINR极化滤波器的性能进行了全面分析.推导出强干扰环境中SINR极化滤波器最优解的解析表达式,构建电磁环境参数空间来综合考虑不同电磁环境参数对滤波性能的影响,详细讨论了滤波性能对信号极化度、干扰极化度及极化匹配系数等参数的复杂依赖关系,最后给出性能分析的相关结论.     

极化敏感阵列抗干扰仿真分析

通过建立极化敏感单元模型,对极化敏感阵列在极化域-空域进行联合抗干扰仿真分析。仿真结果表明,利用极化敏感阵列实现抗干扰的方式,可以拓展抗干扰处理的自由度。同时, 当有用信号与干扰信号同向时,利用有用信号与干扰信号在极化域的差异性可以实现极化域抗干扰。     

极化敏感阵列滤波性能分析:相关干扰情形

研究了相关干扰条件下的极化敏感阵列滤波性能。建立了干扰条件下信号接收模型；利用最小均方误差(MMSE)准则求得相关干扰条件下阵列最优加权矢量和输出最小均方误差；特别考虑了单个相关干扰情况，得出阵列最优加权矢量和输出最小均方误差的具体表达式；通过具体算例分析了相关条件下复相关系数、干扰到达角以及干扰极化状态对滤波性能的影响，并得出了有意义的结论。     

极化轨道约束下的最优极化（一）

本文针对极化测量过程中干扰和噪声对接收效果的影响，提出一种极化轨道约束下的变极化接收方法，以改卷接收系统的SINR（信号干扰噪声比）。在极化轨道约束下的SINR最大化问题是一个寻求局部最优的问题，本文在任意的信号与干扰极化条件下，解决了任意给定的极化轨道上SINR的最大化问题，并对极化轨迈上最优极化与其他两种最优极化得到的SINR进行了比较。     

单脉冲雷达的干扰对消和极化抑制技术

建立了单脉冲跟踪雷达的和、差波束接收通道对目标和干扰信号的接收信号模型,考虑到旁瓣对消目标效应对测角误差的影响,指出利用和、差波束方向图特性的差异可以抑制目标效应,讨论了抑制和通道干扰的方法.基于和、差波束极化方向图的差异,提出了一种空域虚拟极化估计和极化滤波算法,给出了完整的解析表达式,结果表明该技术可对差通道干扰信号具有显著的极化抑制效果,提高信干比,可进一步提高干扰背景下的测角性能.     

On the performance of a polarization sensitive adaptive array

The ability of a least mean square (LMS) adaptive array to adapt to the electromagnetic polarization of incoming signals is considered. An array of two pairs of crossed dipoles is studied. A desired signal and an interference signal are assumed to arrive from arbitrary directions with arbitrary elliptical polarizations. The output signal-to-interference-plus-noise ratio (SINR) from the array is computed as a function of the signal angles of arrival and polarizations. It is shown that as long as certain special desired signal polarizations are avoided, the array is difficult to jam with a single interference signal. To produce a poor SINR, an interference signal must both arrive from the same direction and have the same polarization as the desired signal.     

The tripole antenna: An adaptive array with full polarization flexibility

The performance of an adaptive array using three mutually perpendicular dipoles (a "tripole") is studied. A desired signal and an interference signal, each with arbitrary angle of arrival and polarization, are assumed incident on the array. Uncorrelated thermal noise is also assumed present on each element signal. The output desired signal-to-interference-plus-noise ratio (SINR) is computed as a function of the signal arrival angles and polarizations. It is shown that for most angles of arrival and polarizations, the array has an excellent ability to protect a desired signal from interference. Certain special cases where the performance is not good are discussed in detail.     

Performance analysis of the minimum variance beamformer

We present an analysis of the signal-to-interference-plus-noise ratio (SINR) at the output of the minimum variance beamformer. The analysis is based on the assumption that the signals and noise are Gaussian and that the number of samples is large compared to the array size, and it yields an explicit expression for the SINR in terms of the different parameters affecting the performance, including signal-to-noise ratio (SNR), interference-to-noise ratio (INR), signal-to-interference ratio (SIR), angular separation between the desired signal and the interference, array size and shape, correlation between the desired signal and the interference, and finite sample size     

Array processing for nonstationary interference suppression inDS/SS communications using subspace projection techniques

Combined spatial and time-frequency signatures of signal arrivals at a multisensor array are used for nonstationary interference suppression in direct-sequence spread-spectrum (DS/SS) communications. With random PN spreading code and deterministic nonstationary interferers, the use of antenna arrays offers increased DS/SS signal dimensionality relative to the interferers. Interference mitigation through a spatio-temporal subspace projection technique leads to reduced DS/SS signal distortion and improved performance over the case of a single antenna receiver. The angular separation between the interference and desired signals is shown to play a fundamental role in trading off the contribution of the spatial and time-frequency signatures to the interference mitigation process. The expressions of the receiver signal-to-interference-noise ratio (SINR) implementing subspace projections are derived, and numerical results are provided     

基于粒子群优化的数字波束形成算法

波束形成的加权系数求解是一个优化过程,现有算法大多经过多次迭代,计算量大,实现复杂。为降低波束形成算法复杂度,将粒子群优化原理应用于数字波束形成中,提出了基于粒子群优化的自适应数字波束形成算法。该算法将每一组权值作为一个粒子,将阵列加权和的输出信号与干扰噪声比(SINR)作为适应度函数,通过比较各个粒子的适应度值,进行迭代搜索得到最优解。该算法可使天线阵在主波束对准有用信号,同时能有效抑制两个以上的干扰,且对阵列通道误差有较好的稳健性。计算机仿真验证了算法的有效性。     

水平或垂直极化雷达抗干扰能力的提高

在极化域内分析了极化滤波器的抗干扰能力,指出了其抗干扰能力的有限性,在雷达目标信号为水平或垂直极化情况下,提出了一种极化变换技术,有效地提高了极化滤波器输出的ＳＩＮＲ及增大了在极化域内的干扰抑制范围     

Finite data performance analysis of a sidelobe canceller

The performance of the generalized sidelobe canceller (GSC) is affected by the desired signal (DS) even if all signals are uncorrelated with each other when the DS exists in the received array data with finite snapshot number. Under the condition that the DS is blocked totally in the auxiliary array, a novel expression of the weight vector of the GSC, where the auxiliary array is separated from the main array, is derived for the finite data. Based on the new weight vector, the corresponding expressions of the output signal-to-interference-plus-noise ratio (SINR) can be developed for the case that all signals, including the DS and interference signals, are independent with each other. Then, effects on the SINR for some parameters, including the signal-to-noise ratio, the array antenna number, the direction-of-arrival of the interference signal and the interference-to-noise ratio, are studied, respectively. Some guidelines can thus be obtained for the practical application.