共查询到19条相似文献,搜索用时 140 毫秒
1.
两种声学阵列的定向精度分析与仿真 总被引:8,自引:2,他引:6
声学阵列设计在直升机被动声定位中具有十分重要的意义。本文给出了四阵元十字阵和五阵元十字阵的目标定位方程,分析了其定向精度,并就直升机被动声定向进行了计算机仿真。结果表明,五元十字阵的性能要优于四元十字阵。 相似文献
2.
3.
4.
5.
为更好地应用麦克风阵列识别噪声源位置,本文针对多种不同基阵结构的噪声源识别性能展开研究.基于"延时-累加"波束形成原理建立了平面任意麦克风基阵结构的数学计算模型,并给出了麦克风基阵声源定位的通用计算方程组;分别推导分析了二元、三元及四元基阵的定位算法公式,并对三元基阵给出了其矩阵解.分析比较不同类型的麦克风基阵结构对噪声源的识别性能影响.通过建立由不同形式基阵构成的同等规模小型麦克风阵列,进行噪声源识别对比测试,最终的测试结果验证了本文所提出模型及算法的可靠性,并得出由正三元基阵构成的麦克风阵列结构具有较好的噪声源识别性能的结论. 相似文献
6.
1.引言 在空气声阵列定位技术中,有多种阵型,西方国家广泛采用的对运动目标的定位的小基阵多采用平面正三角型阵(美国HORNET)、平面正四方形阵(美国ADAS)、正四面体阵(瑞典)、五元圆阵、及不规则平面阵等.各种传声器阵列均可以看成是线阵的组合.为此,人们可以从线阵的定位原理出发分析复杂阵型的定位算法,从而建立精确的定位模型.对于固定线阵列来说,阵只能对阵列所在直线为界的半个平面进行定位,否则没有唯一解.对线阵进行组合,构成面阵,就可以对空间目标进行定位.对于低空、超低空飞行的直升机或地面行驶的坦克目标,用平面阵可定位. 相似文献
7.
8.
矢量水听器由声压和振速水听器复合而成,可以共点同步测量声场中的声压与振速。相对于声压阵,使用矢量阵能在大部分观测区域实现无模糊定向,突破半波阵限制,扩展阵列孔径。当导向矢量精确已知和观测数据充分时,MVDR(Minimum Variance Distortionless Response)的分辨率和抑制干扰能力都优于常规波束形成(CBF)。在实际应用中,导向矢量存在误差或者时变,MVDR的性能严重恶化。RCB(Robust Capon Beamforming)是最近出现的一种宽容自适应波束形成算法,该算法直接对导向矢量进行估计作波束形成,从而有效避免了因导向矢量失配性能下降。推导了秩亏情况下的RCB,将其应用到矢量阵,海试结果表明了该方法的有效性。 相似文献
9.
10.
混凝土结构健康检测的声发射圆阵波束形成仿真分析 总被引:1,自引:1,他引:0
采用了声发射(Acoustic Emission,AE)均匀圆阵并分析其波束形成特性,通过仿真分析了阵元数目及声发射模拟信号频率的变化对波束模式的影响.结果表明,当频率不变,阵元数目为4~32时,随着阵元数目的增加,角分辨率保持不变,最高旁瓣降低,可达-8 dB左右.混凝土结构内部缺陷声发射信号的超声频段一般在25~200 kHz,当阵元数目不变时,随着频率的升高,角分辨率随之升高,最高旁瓣也随之增大.另外,文中提出如何设计一个性能相对稳定的阵列,并通过从噪声信号中提取有用信号的实例说明声发射均匀圆阵空间匹配滤波性能. 相似文献
11.
12.
13.
14.
利用角谱理论得到了圆形活塞换能器阵元组阵后作用在平面悬浮物体上的声辐射力分布公式。通过数值仿真,分析了换能器频率、阵元间距以及阵元数目对声辐射力分布的影响。计算结果表明,换能器组阵使得声辐射力分布的指向性变窄,强度增强;随着换能器频率的提高、阵元间距的增大以及阵元数目的增多,声辐射力分布的主瓣更尖锐,但阵元间距的增大会使声辐射力分布的旁瓣增高。为了改善声辐射力的空间分布,采用伪逆矩阵算法,以能量增益为目标函数,通过调节换能器阵元表面振动速度的幅值和相位来形成多焦点的声辐射力分布,为阵列换能器声辐射力分布的调控和声悬浮稳定性的研究提供帮助。 相似文献
15.
16.
Shizeng Lu Qingmei Sui Huijun Dong Yaozhang Sai Lei Jia 《Journal of Modern Optics》2013,60(8):742-749
Acoustic emission location is important for finding the structural crack and ensuring the structural safety. In this paper, an acoustic emission location method by using fiber Bragg grating (FBG) sensors and particle swarm optimization (PSO) algorithm were investigated. Four FBG sensors were used to form a sensing network to detect the acoustic emission signals. According to the signals, the quadrilateral array location equations were established. By analyzing the acoustic emission signal propagation characteristics, the solution of location equations was converted to an optimization problem. Thus, acoustic emission location can be achieved by using an improved PSO algorithm, which was realized by using the information fusion of multiple standards PSO, to solve the optimization problem. Finally, acoustic emission location system was established and verified on an aluminum alloy plate. The experimental results showed that the average location error was 0.010 m. This paper provided a reliable method for aluminum alloy structural acoustic emission location. 相似文献
17.
18.
Application of the concept of acoustic influence coefficients for the optimization of a vehicle roof 总被引:1,自引:0,他引:1
St. Marburg H.-J. Hardtke R. Schmidt D. Pawandenat 《Engineering Analysis with Boundary Elements》1997,20(4):305-310
To improve the acoustic behaviour of vehicles is an increasing challenge for every car manufacturer. The sound pressure at the drivers ear due to an arbitrary excitation of the structure can be calculated by a harmonic analysis first of the structure and then of the fluid. Using the concept of influence coefficients one has to carry out the harmonic analysis of the fluid only once to determine the sound pressure at the drivers ear. If the influence coefficients are available one has to solve an easy algebraic relation instead of a full harmonic analysis. This requires that geometry modifications are small compared with the acoustic wave lengths. So, the computational expenditure is mainly confined to the harmonic analysis of the structure. In this paper, the principal way of carrying out an optimization of a vehicle body is presented for the example of a vehicle roof. The parametric geometry based model of the roof is time harmonically excited. All other parts of the body are considered to remain rigid. Admittance boundary conditions are included. Results are presented for different loads and frequency domains, for limited and for unlimited permissible variations of the geometry and for different modal dampings. 相似文献
19.
为了解决座底式长基线水声跟踪系统的高效校阵问题,结合工程项目实际提出一种智能化分组并行校阵方法。该方法利用水下基阵布阵施工时获得的水声及差分全球定位系统(Differential Global Positioning System,DGPS)测量数据为基准,在校阵试验中采用多个水下基阵分组并行校阵的快捷方式,根据自动反馈的测量数据进行校阵误差收敛测量,当满足事先设定的校准误差后,获得水下基阵的精确位置信息,同时完成多个水下基阵的阵型校准。最后,在某水域采用跑船试验的方式进行验证。长基线系统测量的船只航行轨迹与DGPS轨迹重合性好,证明该方法具有智能化程度高、测量精度高、测阵效率及经济性好等优点,具有较高的军事及民用价值。 相似文献