带内拟合宽带阵列通道误差校正方法

在整个第一Nyquist域进行宽带自适应阵列天线的幅相误差校正时,由于带宽宽,需要的横向滤波器阶数非常高。为了减少滤波器阶数,新方法仅仅对信号带宽内的幅相误差进行校正,采用最小二乘拟合的最优化准则,获得校正滤波器的实系数。同时,通过增加一个前置带通滤波器,保证带外噪声控制在可接受范围内。相对传统方法,该设计在相同滤波器阶数情况下,可以提高带内校正精度。通过对实际MSK信号下的阵列校正实验,证明了新方法的有效性。     

基于阵列扩展的宽带DOA估计算法

导向矢量的频率不一致性不利于宽带信号的DOA估计。为此,首先提出宽带直接空间谱估计算法,但是其限制条件过于苛刻;然后利用宽带信号的时延性质对阵列进行扩展,提出一种新的宽带DOA估计算法,新算法不需要DOA预估计;最后分析了梳妆谱和连续谱两种情形下如何使用新算法的问题。仿真实验结果表明,在信噪比较高的条件下,与传统算法相比,新算法的估计成功率更高,估计误差更小。     

宽带信号阵列测向中的子空间方法

按具体实现途径的不同,将宽带信号阵列测向中的子空间方法划分为非相干信号子空间方法、基于角度预估的宽带相干信号子空间方法、无需角度预估的宽带相干信号子空间方法、投影子空间正交性综合测试方法以及基于频率不变波束形成的宽带相干信号子空间方法等五大类,以各类方法的发展脉络为主线,结合已经提出的各种典型算法,对宽带信号阵列测向中的子空间方法进行了系统、全面的介绍,并对各种方法的优缺点进行了深入分析,提供了详实的参考文献,最后以此为基础,对该研究领域的下一步研究工作进行了展望。     

基于分布式任意阵列的宽带信源定位方法研究

为提高宽带信源的定位精度,在已知信源个数情况下,提出一种新的基于任意阵列的宽带信源定位方法。首先,针对宽带信号的非平稳特性,可将宽带信号利用短时傅里叶变换在频域表示,利用群延迟函数(Group Delay)实现宽带信号的高精度波达方向(DOA)估计;最后根据质心收缩算法和互功率谱相位法以收缩区域的方式进行信源定位。对提出的算法进行了仿真分析,仿真结果表明本文算法DOA估计精度较高,且误差较小,信源定位精度较高。相对于现有的定位方法,本文算法计算量小,精度更高,更具实用性。     

短波宽带阵列信号源的设计与实现

为了在实验室给宽带阵列信号处理设备的研制、维护提供一个较好的仿真环境,介绍了一种基于多片DSP芯片ADSP-TS201S和数字上变频器AD9857构成的宽带阵列信号源,模拟实现了最大带宽为4MHz的短波宽带阵列信号。主要包括系统设计方案、系统硬件设计和DSP软件设计等。     

一种基于GPU的主动声纳宽带阵列信号处理实时系统

该系统采用基于CUDA(Compute Unified Device Architecture,统一计算设备架构)并行编程模型的GPU(Graphic Processing Unit,图形处理器),完成了宽带LFM及CW信号的几种经典波束形成和匹配滤波过程,并实现了系统的实时性处理。实验结果表明：该系统与CPU平台相比,处理速度提高了近一个数量级;与具有同等处理速度的DSP阵列信号处理平台相比,克服了开发周期长、成本高和移植性差等缺点。随着声纳信号处理数据量的日益增大,将GPU强大的通用计算能力应用到声纳领域的各个环节,是一个值得继续深入研究的课题。     

基于改进粒子群算法的宽带测向阵列结构优化

通过对测向模糊性进行分析,提出了针对宽带信号无模糊测向的阵列结构设计方法。该方法基于改进粒子群优化算法,以测向无模糊及各阵元最小间距为条件,对各阵元位置进行优化设计,得到合适的阵列结构以提高阵列的测向性能。仿真实验证明,改进粒子群算法提高了搜索效率,通过本方法设计的测向阵列在测向带宽内能够得到较高的测向性能,而且最小阵元间距不受均匀线阵中阵元间距不大于半波长的约束。     

矢量阵一种简单的相位误差校正方法

分析了矢量水听器阵的阵列流型和误差模型,针对矢量水听器阵列声压和振速通道存在相位误差问题,应用常规波束形成方法和MUSIC方法进行方位估计误差大。并对通道存在估计性能下降的问题,提出了一种简单的相位误差校正方法。利用阵列流型向量在信号子空间的投影,得出存在相位误差的阵列流型向量就是信号子空间的特征值为＂一＂的特征向量,通过与精确的阵列流型向量比较求出矢量阵的相位误差。最后,修正矢量阵的相位误差,得到准确的方位估计能力。通过计算机仿真,验证了算法的可行性和准确性。     

基于凸优化的宽带阵列方向图综合算法

针对宽带任意阵列天线的方向图综合问题,提出了基于凸优化及其求解软件的方向图综合方法.其中针对宽带最低旁瓣方向图综合问题的特殊性,利用了凸优化的优良数值求解特性,以及最新的凸优化求解软件cvx时任意阵列天线的宽带最低旁瓣方向图综合算法进行了有效的建模和求解,获得了满足给定要求的宽带综合方向图.并通过详细的仿真分析验证了所提方法的正确性和有效性,而且优于当前提出的迭代算法.     

Single layer CPSSA array with change polarization diversity in broadband application

The present study proposes a novel broadband circularly polarized (CP) multiple‐input multiple‐output antenna array designed for C‐band applications. The first step was the introduction of a reconfigurable circularly polarized square slot antenna (CPSSA) capable of changing polarization diversity, which could cover impedance bandwidth (BW) from 4.48 to 8.21 GHz with 1.9 GHz of ?3 dB axial ratio (AR) BW. Then, a feed network composed of 90° and 180° couplers, a crossover, and delay lines was presented. The CPSSA with two metalized via‐holes adopted with two ports polarization diversity fed the networks. A number of reconfigurable CP array antennas using the polarization diversity technique have been presented so far. However, given that the proposed layout designed in a single layer had advantages of reduced antenna size and increased antenna gain and ARBW, this approach has received due attention over recent years. Another promising feature of this approach is its capability to change the polarization diversity by rotation of phases in the array feed network using PIN diodes.     

A broadband quasi‐Yagi array of rectangular loops on LTCC

In this article, a broadband quasi‐Yagi array of rectangular loops using low‐temperature co‐fired ceramic technology is proposed. The antenna is fed by a simple and compact microstrip‐to‐coplanar strip transition, which serves as balun and impedance transformer simultaneously. Four rectangular loops are used to direct the antenna propagation toward the end‐fire direction. Compared with the planar directors in traditional quasi‐Yagi antenna, they can provide better director effect to improve the radiation performance. Furthermore, they act as good impedance matching elements to broaden the bandwidth. The measured results show that the proposed antenna achieves a wide bandwidth of 42% for S₁₁ < ?10 dB (from 26.1 to 40 GHz), better than 12 dB front‐to‐back ratio, smaller than 14 dB cross polarization and an average gain over 6.5 dBi across the operating bandwidth. The antenna occupies a compact size of 8 × 8 × 1 mm³. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:196–203, 2014.     

利用麦克风阵列的管道主动噪声控制方法

空调通风管道在运行时, 内部出现的低频噪声很难通过包裹消音材料等被动式降噪方法消除. 而在部署主动噪声控制时, 会出现声反馈现象, 影响降噪性能甚至造成控制系统的响应发散. 针对这种声反馈现象, 本文在分析其产生原因的基础上, 将麦克风阵列作为前馈, 对Duvall-Frost结构的线性约束最小方差波束成形算法加入预调向,提出了利用麦克风阵列的管道主动噪声控制方法, 实现单方向拾取来自管道上游的噪声信号, 避免声反馈带来的影响. 并利用滤波器x最小均方误差(FxLMS) 算法作为自适应控制算法, 针对4种典型低频噪声, 在真实管道环境下进行主动降噪实验. 实验结果表明, 相比不使用麦克风阵列的情况, 本文提出的主动噪声控制方法能达到明显的降噪性能, 且在稳定性方面取得较好结果.     

Antipodal tapered slot antenna array using broadband decoupling structure for mutual coupling reduction

In this article, an effective method to reduce the mutual coupling between the antipodal tapered slot antenna (ATSA) array is proposed. This method is mainly implemented by loading a set of decoupling structures (DS) perpendicular to the dielectric substrate between two antenna elements. The proposed DS can provide transmission forbidden band which can effectively prevent leaked electromagnetic waves. DS can operate in most frequency bands within 4 to 17.5 GHz. It can enhance about 23 dB isolation between the ATSA array without affecting bandwidth and radiation characteristics. The proposed ATSA arrays are fabricated and tested. The measured results can verify its excellent properties. The proposed broadband decoupling method is a suitable candidate for restrain mutual coupling of ultra‐wideband planar end‐fire antennas. This design sheds new light on broadband decoupling.     

Posture estimation of hose-shaped robot by using active microphone array

Hose-shaped rescue robots have been developed for searching narrow spaces such as under collapsed buildings. The posture estimation independent of the past history is critical, because conventional inertial-sensor-based posture estimation has two main problems; a cumulative error problem peculiar to inertial sensors, and a sudden posture change problem caused by external forces. For coping with the two problems, we developed a novel posture estimation method by putting an active microphone array, a set of microphones and loudspeakers, on the robot. The method calculates the time difference of arrival (TDOA) of the reference signal emitted from one loudspeaker, and estimates the posture from the distance obtained by TDOA. This concise method still has three problems: (1) external noise, (2) reverberation and reflection, and (3) obstacles. These problems are tackled by (1) TSP signal, (2) GCC-PHAT and a threshold-based onset detection, and (3) rejecting incorrect onset times, respectively. Experiments with simulated sounds and actual recordings demonstrate that the method attains the performance of estimation comparable to that of conventional methods, that is, less than 20 cm of the tip position error. Even without historical data, the method attains the similar performance while conventional methods fail.     

一种近场麦克风阵列后滤波语音增强方法

介绍了一种用于近场麦克风阵列后滤波语音增强的方法,避免了现有的利用自功率谱密度和互功率谱密度的Zelinski和McCowan后滤波器中噪声功率谱过估计的问题,并加入了近场传播的幅度衰减补偿和相位延迟补偿。使用卡内基梅隆大学提供的多麦克风语音数据以及使用Habets E A P提出的生成阵列散射噪声的方法进行的仿真实验,证明了改进的方法在语音质量客观评估量方面优于Zelinski后滤波法和McCowan后滤波法。     

基于麦克风阵列的声源定位系统设计

从系统的角度对真实声场环境下基于到达时间差的声源定位算法进行了研究,搭建了基于麦克风阵列的声源定位系统,将LabVIEW应用于声源定位软件的开发,方便地完成信号的采集与处理,运用广义互相关函数法进行时延估计,结合平面四元十字阵模型建立方程组实现定位。该系统人机界面友好,具有较强的数据分析和处理能力,能及时跟踪声源的位置变化。     

混响环境下的宽带波束形成语音增强方法

结合小波滤波器组理论和自适应波束形成技术,提出了一种基于宽带波束形成的麦克风阵列语音增强方法。该方法利用小波分析滤波器组将含噪语音信号变换到小波域;进行小波域阵列自适应波束形成;通过小波综合滤波器组重构增强后的语音信号。计算机仿真实验验证了该方法的有效性。     

麦克风阵列声源定位与跟踪性能改进

针对将线形全向麦克风阵列应用于室内声源定位与跟踪时出现的对称双主瓣、空间角分辨率下降、选择性频率衰落等问题,提出了相应的解决方法。联合使用所提出的三个方法,将大幅度提高室内线形全向麦克风阵列声源定位与跟踪的性能,而不必改变阵列拓扑结构、不增加硬件成本。