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1.
直升机载相控阵雷达波束波形联合自适应调度算法研究   总被引:1,自引:0,他引:1  
孔径分割技术和波形捷变能力让直升机雷达可同时形成多个波束完成不同功能,并根据不同需求选择不同波形,因此对雷达资源管理提出更高的要求;综合考虑时间资源、能量资源、孔径资源的约束下,提出一种适合于多子阵直升机载相控阵雷达的波束波形联合自适应调度算法,对雷达波束和波形进行有效调度,并通过与传统自适应调度算法进行仿真对比,证明了该算法在调度能力、能量节约等方面的先进性。  相似文献   

2.
云计算环境下资源调度系统设计与实现   总被引:1,自引:0,他引:1  
张露  尚艳玲 《应用声学》2017,25(1):131-134
在云计算环境下,对开放的网络大数据库信息系统中的数据进行优化调度,提高数据资源的利用效率和配置优化能力。传统的资源调度算法采用资源信息的自相关匹配方法进行资源调度,当数据传输信道中的干扰较大及资源信息流的先验数据缺乏时,资源调度的均衡性不好,准确配准度不高。提出一种基于云计算资源负载均衡控制和信道自适应均衡的资源调度算法,并进行调度系统的软件开发和设计。首先构建了云计算环境下开放网络大数据库信息资源流的时间序列分析模型,采用自适应级联滤波算法对拟合的资源信息流进行滤波降噪预处理,提取滤波输出的资源信息流的关联维特征,通过资源负载均衡控制和信道自适应均衡算法实现资源调度改进。仿真结果表明,采用资源调度算法进行资源调度系统的软件设计,提高了资源调度的信息配准能力和抗干扰能力,计算开销较小,技术指标具有优越性。  相似文献   

3.
黄聪  孙大军  张殿伦  滕婷婷 《物理学报》2014,63(18):188401-188401
双基地多输入多输出(MIMO)系统需要对目标的波达角和波离角进行二维估计,针对高分辨算法中阵列协方差矩阵处理运算量大以及估计性能对阵列流形失配敏感的缺陷,提出了一种基于二阶锥规划的抗阵列流形失配的双基地MIMO虚拟阵列波束优化算法.该方法利用MIMO的波形分集技术与双基地的目标定位解算,通过波达角和波离角在双基地定位椭圆上的对应关系,将双基地MIMO的二维合成方向矢量转化为一维的虚拟阵列流形,并证明了双基地MIMO虚拟阵列的波束图等效为发射波束图在接收阵角度域上的响应和接收波束图的合成.在优化波束图旁瓣的同时,该算法兼顾了固定方向上的相干干扰抑制,并提高了双基地MIMO虚拟阵列波束优化抗阵列流形失配的能力.通过波束图和方位谱优化的仿真分析和水池试验,验证了算法的有效性.  相似文献   

4.
理论上,自适应波束形成方法要比不依赖于输入数据的常规波束形成方法有更好的目标参数估计能力和干扰抑制能力.但在实际水声环境中,声传播模型、接收阵阵列流形以及信号统计特征等因素往往与实际情况存在一定的差异,导致传统的自适应波束形成方法性能下降.因此,提高自适应波束形成方法对上述因素的鲁棒性变得越来越重要.本文基于最差条件最优化的思想,改进MVDR(最小方差无失真响应)方法的约束条件提出了一种鲁棒性最小方差无失真响应自适应波束形成算法(R-MVDR),并对输入数据协方差矩阵和方向向量存在不确定性的情况进行了性能分析,推导给出了波束形成的加权向量和空间谱估计表达式,最后通过海上实验数据进行了验证.结果证明本文提出的算法在实际环境中有更好的方位分辨能力和干扰抑制能力.  相似文献   

5.
峰值能量检测及其在被动声纳显示中的应用   总被引:1,自引:0,他引:1       下载免费PDF全文
本文介绍子带峰值能量检测方法及其在被动声纳显示和检测中的应用[2-4],同时提出了波束域宽带峰值能量检测算法。新的波束域算法是在已有波束形成的基础上进行处理,不需对原系统进行较大的修改。通过波束域宽带峰值能量检测处理,可以改善声纳显示效果,更加清晰地显示目标方位。相对于高分辨率波束形成算法,两种峰值能量检测算法的运算量都比较低,具有一定的工程应用前景。通过计算机仿真和实测数据处理,验证了所述两种峰值能量算法在提高显示清晰度,减小测向模糊度方面的优点。  相似文献   

6.
罗慧兰 《应用声学》2017,25(12):150-152, 176
为了缩短云计算执行时间,改善云计算性能,在一定程度上加强云计算资源节点完成任务成功率,需要对云计算资源进行调度。当前的云计算资源调度算法在进行调度时,通过选择合适的调度参数并利用CloudSim仿真工具,完成对云计算资源的调度。该算法在运行时有效地进行平衡负载,导致云计算资源调度的均衡性能较差,存在云计算资源调度结果误差大的问题。为此,提出一种基于Wi-Fi与Web的云计算资源调度算法。该算法首先利用自适应级联滤波算法对云计算资源数据流进行滤波降噪,然后以降噪结果为基础,采用本体论对云计算资源进行预处理操作,最后通过人工蜂群算法完成对云计算资源的调度。实验结果证明,所提算法可以良好地应用于云计算资源调度中,有效提高了云计算资源利用率,具有实用性以及可实践性,为该领域的后续研究发展提供了可靠支撑。  相似文献   

7.
协方差矩阵重构的稳健自适应波束形成算法   总被引:1,自引:0,他引:1       下载免费PDF全文
王昊  马启明 《声学学报》2019,44(2):170-176
针对协方差矩阵含有期望信号成分以及波束指向角失配时,传统自适应波束形成器性能严重下降的问题,提出了协方差矩阵重构的稳健自适应波束形成算法。该算法将全空域划分成若干互不重叠的区域,分别对应干扰区域与信号区域,先利用Capon波束形成器对干扰区域积分,由此构造出干扰协方差矩阵。然后,利用标准Capon波束形成器的波束域MUSIC谱估计法对信号区域积分,重构出信号协方差矩阵,以其主特征向量作为期望信号导引向量估计。由于算法重构了干扰加噪声协方差矩阵并对导引向量进行了修正,保证了自适应波束形成器的性能。理论分析和仿真实验结果表明,算法在训练数据含有期望信号成分和波束指向角度失配情况下具有良好的性能。   相似文献   

8.
波束形成在声纳/雷达信号处理中占有重要的地位,而设计出满足要求的波束形状是声纳/雷达信号空间处理的重要内容。自适应波束形成算法理论上可以获得最优的工作性能,但其计算复杂度高、宽容性差等缺点严重地限制了这些算法的实际应用。本文采用基于模式搜索的波束优化算法,获得了与实际接收数据无关的、类似于窗函数的幅度权系数。与加窗波束形成算法相比,这种方法可以在保证主瓣宽度不展宽的情况下,有效降低旁瓣级,并且,这种方法对基阵的几何形状没有任何限制。  相似文献   

9.
杨晴  王良 《应用声学》2017,36(2):168-174
逆波束形成较常规波束形成有较好的方位分辨力,但其旁瓣较高,为抑制旁瓣并进一步提高阵增益和方位分辨力,本文提出一种自适应逆波束形成方法,通过设计自适应滤波器对虚拟阵列进行加权,提高阵增益和方位分辨力。理论分析表明自适应逆波束形成能够抑制旁瓣和噪声,阵增益较常规波束形成和逆波束形成提高约3 d B,数值仿真结果表明,自适应逆波束形成的旁瓣降低,阵增益和方位分辨力提高,实验数据处理结果表明自适应逆波束形成具有良好的方位分辨能力和目标检测能力,从而验证了其抑制旁瓣、提高方位分辨力和阵增益的有效性。  相似文献   

10.
刘兢本  郭良浩  董阁  闫超 《应用声学》2023,42(2):202-216
针对常规波束形成主瓣宽且目标分辨能力低的问题,提出一种基于深度卷积神经网络的波达方向估计方法。算法使用常规波束形成计算二维空间功率谱,将预处理后的空间功率谱图输入深度卷积神经网络。该文利用神经网络学习解卷积映射关系,输出主瓣宽度更窄的空间功率谱图,从而实现高分辨率二维波达方向估计。该算法对阵列结构没有限制,适用于立体阵。仿真结果表明该文方法在不同目标个数、快拍数及信噪比参数下均能准确估计目标方向。该文方法目标分辨能力优于常规波束形成方法。在低快拍情况下,目标方向估计误差低于自适应波束形成方法。  相似文献   

11.
In this paper,a high-efficiency aerothermoelastic analysis method based on unified hypersonic lifting surface theory is established.The method adopts a two-way coupling form that couples the structure,aerodynamic force,and aerodynamic thermo and heat conduction.The aerodynamic force is first calculated based on unified hypersonic lifting surface theory,and then the Eckert reference temperature method is used to solve the temperature field,where the transient heat conduction is solved using Fourier’s law,and the modal method is used for the aeroelastic correction.Finally,flutter is analyzed based on the p-k method.The aerothermoelastic behavior of a typical hypersonic low-aspect ratio wing is then analyzed,and the results indicate the following:(1)the combined effects of the aerodynamic load and thermal load both deform the wing,which would increase if the flexibility,size,and flight time of the hypersonic aircraft increase;(2)the effect of heat accumulation should be noted,and therefore,the trajectory parameters should be considered in the design of hypersonic flight vehicles to avoid hazardous conditions,such as flutter.  相似文献   

12.
遥测实时监控是保障试飞安全、提高试飞效率的重要手段。针对舰上特殊的试飞环境限制,现有遥测系统不能适应其任务需求,为完成某型号飞机舰上试飞任务,需要对现有遥测接收系统进行改进,以应对特殊试飞科目下对遥测信号的需求。采用跟踪接收机模块,并开发相应的解调模块,对系统设备进行远程控制解决了远距离数据传输的信号衰减问题;对遥测系统的自动温度控制大大提高了系统设备的环境适应性;通过接口转换实现模拟图像的网络输出、接收机模块和天线的网络串口转换,简化了信号接口类型,降低了信号传输的难度;从而实现小型化的舰基遥测综合解调控制系统设计。  相似文献   

13.
A theoretical technique for predicting the flutter characteristics of a helicopter rotor is presented. The effect of phase angle on flutter speed of a two-bladed rotor in hovering and axial flight is determined. For this purpose, a uniform and untwisted rotor blade with coupled flapwise bending and torsional degrees of freedom is considered. The transmission matrix method is used to obtain the natural vibration characteristics of the system. An unsteady aerodynamic theory is used to obtain the aerodynamic loading in compressible flow.  相似文献   

14.
A flow field modified local piston theory, which is applied to the integrated analysis on static/dynamic aeroelastic behaviors of curved panels, is proposed in this paper. The local flow field parameters used in the modification are obtained by CFD technique which has the advantage to simulate the steady flow field accurately. This flow field modified local piston theory for aerodynamic loading is applied to the analysis of static aeroelastic deformation and flutter stabilities of curved panels in hypersonic flow. In addition, comparisons are made between results obtained by using the present method and curvature modified method. It shows that when the curvature of the curved panel is relatively small, the static aeroelastic deformations and flutter stability boundaries obtained by these two methods have little difference, while for curved panels with larger curvatures, the static aeroelastic deformation obtained by the present method is larger and the flutter stability boundary is smaller compared with those obtained by the curvature modified method, and the discrepancy increases with the increasing of curvature of panels. Therefore, the existing curvature modified method is non-conservative compared to the proposed flow field modified method based on the consideration of hypersonic flight vehicle safety, and the proposed flow field modified local piston theory for curved panels enlarges the application range of piston theory.  相似文献   

15.
A reliability analysis of suspension bridges against flutter failure is presented using the basic theory of reliability. For the purpose of analysis, uncertainties considered are those arising from the variations in geometric and mechanical properties of bridge, modelling, damping and experimentally obtained flutter derivatives. These uncertainties are incorporated by multiplying the computed flutter wind speed with a number of independent factors, which are considered as random variables. Each factor is assumed to follow log-normal distribution. The wind environment at the site, which may cause flutter failure, is considered as the other uncertainty necessary for computing the reliability against flutter failure. The flutter wind speed for the bridge is determined using a finite element approach and a multimode analysis. The effect of some important parameters such as the mean wind speed at the site, coefficients of variation of the multiplying factors associated with damping, modelling and flutter derivatives on the reliability estimates is investigated. The results of the study show that the reliability against flutter failure is sensitive to the variation of the above parameters.  相似文献   

16.
三维透平叶片扭转颤振问题的流固耦合数值研究   总被引:4,自引:0,他引:4  
颤振,尤其是失速颤振是引起叶轮机械安全事故的重要原因之一。由于叶片颤振的复杂性,过去人们一直采用半经验的方法研究叶片的颤振。本文发展了一套更精确的流固耦合计算方法,并用这种算法研究了三维透平叶片的扭转颤振。在模拟大负攻角下的颤振时发现,传播失速响应频率向固有频率靠近是振动发散的一个重要判据。通过计算得出了压比和攻角对颤振影响的特性曲线,它不但可用于判断流体激振的稳定性,而且可以研究颤振的强度。  相似文献   

17.
This paper explores the use of the proper orthogonal decomposition (POD) method for supersonic nonlinear flutter of a cantilever plate or wing. The aeroelastic equations are constructed using von Karman plate theory and first-order piston theory. The two-dimensional POD modes (POMs) in xy plane are determined from the chaotic results given by the traditional Rayleigh–Ritz (RR) approach. For a specific structure, the POMs need to be calculated once and then can be used for various parameters of interest. The derivatives of the POMs are calculated numerically to avoid the complex projection from the POMs to the Rayleigh–Ritz modes (RRMs). Numerical examples demonstrate that the POD method using 4 POMs can obtain accurate limit cycle oscillation (LCO) results with substantial computational cost savings, compared with 12 RRMs by the Rayleigh–Ritz method. The POD method is employed for the analysis of the chaotic oscillations. It is also demonstrated that the POD modes are robust over a range of flight parameters.  相似文献   

18.
X射线脉冲星导航半物理仿真实验系统研究   总被引:3,自引:0,他引:3       下载免费PDF全文
苏哲  许录平  王婷 《物理学报》2011,60(11):119701-119701
由于费用巨大,X射线脉冲星导航初步研究阶段不可能进行空间搭载实验.为此,文章设计了一种X射线脉冲星导航半物理仿真实验系统.该系统由脉冲星信号模拟部分和导航参数解算部分组成.模拟部分采用非齐次泊松过程对光子到达太阳系质心的时间建模,时间转换后,模拟X射线探测器观测脉冲星时输出的脉冲信号.导航参数解算部分利用Delta-Correction方法解算模拟信号中蕴含的导航信息.该系统可同时模拟4颗脉冲星信号,成本低,精度高,可对脉冲星导航的信号处理和参数解算过程进行光子级仿真研究,并为后续空间搭载实验中原理样机的设计提供一定的参考. 关键词: X射线脉冲星 导航 仿真实验系统 非齐次泊松过程  相似文献   

19.
为了了解采用脉冲CO2激光推进空气呼吸模式时光船参数等对产生等离子体的影响,介绍了利用实验室自行研制的紫外预电离TEA CO2激光器进行的激光等离子体实验。实验采用底面直径为60mm、焦距为5mm和10mm的抛物面光船。介绍了空气呼吸模式激光等离子体的谱和明显的特征谱线,以及等离子体的时间演化过程。结果表明:空气呼吸模式等离子体的持续时间约为20μs,在6μs左右时信号强度达到最大值;激光脉冲作用后,信号迅速衰减;10mm光船产生的等离子体信号峰值和持续时间均略长于5mm光船的。  相似文献   

20.
Research on stress evaluation of laser cladding coating with critically refracted longitudinal wave was introduced in this paper. Two critically refracted longitudinal wave transducers with 5 MHz frequency, spacing between which was constant, were employed as signal emitter and receiver. Based on acoustoelastic equation deduction, relationship between the difference in time of flight and tensile stress is obtained. Combing with cross correlation theory, the difference in time of flight between stressed and unstressed critically refracted longitudinal signals was calculated. Results show that stress evaluation is affected by layer interface and anisotropic microstructure of laser cladding coating, precision of stress evaluation of laser cladding coating increases as step length increases until it attains one cycle. In addition, influence of waveform distortion caused by microstructure of laser cladding coating on stress evaluation is discussed. At last, verification test is carried out and the experimental result is well consistent with theoretical result.  相似文献   

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