共查询到18条相似文献,搜索用时 62 毫秒
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为了有效地解决在低信噪比下宽带目标的被动声纳检测问题,本文将传统的用于声源定位的双水听器互相关方法扩展为多水听器互相关方法,通过多个水听器的输出信号的相干累加实现了在接收端的信噪比的提升。首先使用宽带滤波,计算得到各个水听器关于假定声源位置的信道解调信号,其次计算两组水听器的输出累加信号的时域互相关,最后对时域互相关进行阈值检测。仿真结果表明,相比于双水听器,多水听器互相关方法能够在更低信噪比下实现宽带目标检测。此外,考虑到求解滤波器系数需要很大的计算量,本文提出了运用互易性原理的加速方案。仿真结果表明互易性原理可以有效地降低求解滤波器系数的计算量。 相似文献
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被动声纳信号检测技术研究 总被引:1,自引:0,他引:1
论文介绍了被动声纳工作原理及被动声纳信号的检测原理,分析了采用Chirp—z变换进行频谱细化的方法,并使用Matlab进行仿真。仿真结果表明,Chirp-z变换可使频谱细化,提高局部频段内的分辨能力。采用该算法对被动声纳检测线谱进行处理,使系统的整体检测性能有较大的提高。 相似文献
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宽带数字阵列雷达(DAR)中跨距离单元走动(ARU)、匹配滤波器失配以及孔径渡越问题降低了高速微弱目标的检测性能。为此,该文给出一种宽带时空Radon-Fourier变换(WST-RFT)相参积累方法。该方法基于DAR 3维回波模型给出了宽带匹配滤波器系统响应函数,并通过联合搜索目标3维参数空间,同时解决ARU、匹配滤波器失配和孔径渡越问题。给出了基于WST-RFT检测器的最优性证明。针对WST-RFT 3维参数空间遍历搜索运算量大的问题,该文进一步给出了基于Chirp-Z变换(CZT)的WST-RFT快速算法。最后,数值实验结果验证了该文所提方法的有效性。 相似文献
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智能宽带声纳发射机的研制 总被引:1,自引:0,他引:1
在主动式声纳系统中,信号产生器、功率放大器和发射换能器等组成的发射机是不可或缺的.传统的水下声纳发射机存在效率低,功率小,带宽窄,功能简单及易损坏等缺点.该文提出了一种大功率、小体积且包含信号产生、监控与通信等功能的智能宽带声纳发射机的设计方案.该方案以现场可编程门阵列(FPGA)为核心,采用移相脉宽调制(PWM)的D类功率放大器结构.湖试和海试表明,以此方案设计的声纳发射机达到了1.03 kw的平均输出功率、84%的效率及50%的带宽.从制成至今2年时间,发射机工作一直稳定可靠. 相似文献
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提出一种基于匹配场和长项积分混合处理的被动检测跟踪一体化算法.将贝叶斯准则下的概率数据关联技术引入匹配场和长项积分混合处理,构造检验统计量,计算后验关联概率,建立起从跟踪器到检测器的信息反馈;在跟踪进程中分别采用单一模式和多模式组合对目标的运动状态进行近似.给出了一体化算法的仿真实例,并利用一组海试数据对算法的有效性进行了验证. 相似文献
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A. S. Makarenko 《Radioelectronics and Communications Systems》2010,53(10):566-568
A device has been proposed for enhancing the signal-to-noise ratio at the output of optimal filter during the detection of
weak video pulses. This effect was achieved at the expense of cutting off the negative surges of noise by the instantaneous
nonlinear circuit having the characteristic of “linear detector” (diode with resistive load) connected before the optimal
filter. The computational relationships were presented and the calculation results were corroborated by experimental data 相似文献
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Moran PR 《IEEE transactions on medical imaging》1982,1(3):197-204
To filter an image by an aperture function A(r), or in Fourier space by its transform A(f), requires that A(r) and A(f) are physically realizable and mathematically exist as transform pairs. This constrains both functions to being square-integrable to guarantee their uniform convergence both in spatial and frequency domains. This paper presents a general method for deriving filter forms which maximize image SNR and also satisfy the existence constraints. We show that asymptotic limiting forms of the constrained filters reduce to the "ideal observer" result, but demonstrate that the "ideal" filter form has a divergent square integral in some simple cases important in medical imaging. We apply these properly constrained filter forms to radiographic image and CT image models, and derive the range of arguable signal-to-noise advantage, which "more" optimum filters may exhibit with respect to the simple "matched" filter limit. 相似文献
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LiangChao Li JianYu Yang GuoLong Cui ZhengMao Jiang Xin Zheng 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(1):102-115
This paper mainly deals with the problem of detecting and identifying target in close range, the performance of which will
be effected by the radiometer’s parameters and target’s characteristics. According to the relationship between the range equation
of the Passive Millimeter Wave (PMMW) and these parameters, we present a convenient statistical method based on PMMW image
detection to solve the inherent problem by statistical radiometer parameters, which can be achieved by the W band radiometer
experimental data. Finally, we validate the method by simulation and experiment. The results show that the method is convenient
for detecting and identifying target in close range. 相似文献
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常规宽带能量检测在多目标、强干扰环境下输出信噪比(SNR)降低,检测性能大幅度下降.针对此问题,该文提出一种将子阵导向最小方差(STMV)宽带空域自适应波束形成与频域Eckart滤波结合的空-频联合最优滤波宽带检测方法.该方法首先通过子阵导向最小方差波束形成进行空间自适应处理,利用自适应波束形成的干扰抑制能力在空域实现最优滤波;然后通过最大似然估计实时估计信号和噪声的功率谱,构造Eckart滤波对自适应波束形成的输出分配不同权重进行加权滤波,从而实现频域信噪比最大化.所提方法通过空-频联合最优滤波,降低空域旁瓣干扰和频带内噪声的影响,使得输出信噪比最大,从而有效地改善目标宽带检测能力,提高被动声呐的宽带检测性能.仿真和试验数据处理结果验证了该方法的有效性. 相似文献