查询词典 DOA

The main job and contribution of this paper are as follows:Based on narrowband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, compute the cross-correlation function of FH signals from multichannels, then we get the cross power spectral density matrixCSDM Secondly, select the hops of FH signals from the CSDM via processing and analyzing the CSDM, meanwhile reduce the influence coming from noise, fixed frequency signal and other interferences; Lastly, estimating the DOA of every hop and according to the DOA, we can separate the hops, get the number of FH signals and their parameters. Propose a new method for designing the threshold in FH signal detection. This method makes it easy to get the threshold by theoretic computing and it can extremely reduce the interference of non-FH signals.Based on broadband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, get the DOA of the signals by wideband spatial spectrum estimation; secondly, separate the signals by spatial filtering using wideband beamformer; Lastly, we propose two methods for FH signal blind detection and blind parameter estimation, one is for several constant hop-rate FH signals whose dwell-time are different and another is for a single FH signal whose hop-rate is alterable.By employing spatial interpolation in broadband signal beamforming, it can reduce the number of antenna elements and corresponding RF modules, A/D converters, etc. It can also eliminate the mutual coupling between antenna elements while getting the narrower main beamwidth and lower sidelobe level.

本文的主要研究工作和贡献如下：●提出了一种基于窄带处理的FH信号盲检测和参数盲估计的实现方法，即首先求出多路信号之间的互相关，进而得到互功率谱密度矩阵，然后通过对CSDM进行对折处理来抑制噪声、定频信号及其他干扰的影响，并将所有属于FH信号的hop(每一跳的驻留时间在时频图上持续的线段)从CSDM中筛选出来，最后用阵列信号处理中的到达方向估计理论在频域中估计出各个hop的方向参数，利用方位信息完成FH信号分离并得到FH信号的数目及其各自的参数集；●提出了一种确定FH信号检测门限的策略，该策略不仅使得检测门限能够通过理论计算得到，而且还显著地抑制了非跳频信号的干扰，从而能有效地检测出FH信号；●提出了一种基于宽带处理的短波FH信号盲检测和参数盲估计的实现方法，即首先利用宽带空间谱测向技术得到接收信号的DOA，然后采用宽带波束形成技术对特定方向进行空间滤波，实现多个信号的分离，最后分别提出了两种FH信号的盲检测和参数盲估计方法，第一种方法适用于空间某个特定方向上存在着几个驻留时间不同的恒跳速FH信号和其他干扰信号的混合信号，第二种方法适用于空间某个特定方向上仅含一个可变跳速的FH信号和噪声的混合信号；●将空间插值的概念和宽带波束形成技术结合起来，提出了一种基于频域处理的宽带恒定束宽的波束形成方法。

The ambiguity of DOA estimation due to ignorance of the function form of angular signal distribution is analyzed and the DOA estimation without ambiguity is given. 4. A method of DOA estimation of distributed sources is proposed by using the knowledge of the unimodal property of angular signal distribution and independence between different distributed sources.

利用角信号分布函数的共轭对称性，提出了基于噪声子空间的极小最小特征值一维搜索分布式目标DOA估计方法，和基于信号子空间的极大最大特征值一维搜索分布式目标DOA估计方法。

In this paper, the DOA-matrix subspace method is extended for DOA estimation with an array of electromagnetic vector sensors.

DOA矩阵法是一种二维波达方向估计方法，该方法具有分辩率较高、计算量较少的特点。

Capon method for DOA estimation, the program is irrelevant to the three incoming signals DOA estimation.

详细说明： Capon法进行波达方向估计，该程序对3个不相干入射信号进行波达方向估计。

In this paper, we analysis signal model of multi-path environment, and use high order cumulant method, together with some general DOA estimating method, to estimate DOA of multi-path accurately.

本文针对多径的影响，分析了多径情况下的信号模型，并采用基于高阶累积量的方法来解决多径情况下的DOA估计。

The using of the technologies of DOA in the orientation estimating of interference is discussed, then an evolutive ESPRIT algorithm is put forward which avoids the eigendecomposition and is easily achieved. To the MUSIC algorithm, an easy eigendecomposition algorithm for Hermitian matrix is presented. It breaks away form the complex matrix decomposition such as QR algorithm. Basing on the whole matrix, the algorithm makes use of the multiplication operation of matrix and vector, which attains simpleness and is fit for DSP. In the field of DOA estimating of correlation interferences, spatial smoothing algorithm consumes too many array units.

讨论了DOA技术在干扰源方位估计中的应用，提出了一种ESPRIT演变算法，该算法避开了特征值分解，实现简便；在MUSIC算法的实现中提出了一个Hermitian矩阵特征值分解算法，该算法摆脱了复杂矩阵分解，从矩阵整体出发，主要的运算是矩阵与矢量的乘运算，算法简单，非常适合DSP芯片实现；在相关源的DOA估计中，空间平滑技术使阵元的损失非常大，本文提出了一种进一步降低阵元消耗的平滑技术—随机空间增益法，其在运算量上的增加很小，但对于相干源的去相关确是有效的。

To overcome the local optimal problem existing in some maximum likelihood DOA estimation algorithms, improve the estimation accuracy, a global optimal solution of nonlinear maximum likelihood DOA estimation is obtained by real-valued genetic algorithm proposed in this paper.

所提出的实数遗传算法由含实数域结构和目标函数信息的实数交叉和变异算子构成，是较理想的获取非线性实变量函数全局最优解的方法。

Based on the decomposition of the space time eigenstructure of signals,a novel wideband spectral correlation space time DOA matrix method is proposed in this paper to estimate the 2 D DOA of wideband signals .

该方法利用信号的循环平稳特性实现了对宽带信号的有效处理，同时通过空时变换将传统的一维空域处理拓展到了二维空时处理，更充分地利用了信号的时域特征，从而大大简化了阵列结构，提高了算法的性能。

Correlation and signal-to-noise ratio of the space sources can affect the resolution of DOA estimation of subspace algorithms. Using this relation, the algorithm changes the correlation and SNR of the equivalent sources by processing the Toeplitz matrix based on the Toep-MUSIC algorithm, so that the resolution of DOA estimation can be improved.

改进算法利用信源间相关性和信噪比对子空间类DOA估计算法分辨力的影响，在Toep-MUSIC算法基础上，通过对Toeplitz重构矩阵的处理，改变了等效信源的相关系数和信噪比，从而使DOA估计分辨力得到提高。

Simulation results show that the proposed algorithm estimates the DOA of multipath signals effectively and acceptably.

仿真结果显示，该算法对于多径信号的DOA估计是有效和可靠的，具有低复杂度、简便、易实现的优点，适合于实际系统的应用。

In the days of sailing vessels the crew were afraid they would be becalmed on the ocean.

在使用帆船的时代，船员们担心他们会因为无风而无法在海洋上航行。

As long as foreign donors pay the PA's salary bill, few expect a new intifada.

只要外国继续为巴权力机构的薪水买单，希望发动新暴动的人便寥寥无几。