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广义复合杂波分布(Generalized Compound Probability Density Function,GC-PDF)模型是一种适用范围广泛的杂波分布模型,参数估计是研究该杂波模型的关键技术.本文首先建立了广义复合杂波模型,推导了其统计特性.在此基础上,研究了最小二乘参数估计方法.进而,以参数解耦和充分利用杂波序列信息为突破点,提出了一种新的杂波模型参数估计算法.该算法将一个四维非线性最优化问题转化为一个一维线性最优化问题,从而降低了计算量和所需样本数,提高了估计性能.最后,进行了仿真实验,验证了本文的结论.该算法对于高分辨雷达杂波分类和识别以及基于杂波背景的目标检测具有重要意义. 相似文献
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高分辨率雷达杂波建模与仿真是评估雷达性能的重要手段。广义复合概率密度通常用来描述高分辨率雷达杂波。在广义复合分布中,将散斑分量和调制分量均采用广义伽马(GΓ)分布来表示。采用球不变随机矢量(SIRV)进行杂波建模的优点在于能够独立控制其相关性和一维边缘概率密度。对广义复合分布和SIRV建模方法进行了讨论,在此基础上,给出了相干相关的广义复合分布的SIRV模型,利用计算机进行了广义复合分布的杂波仿真,并对杂波仿真的统计特性与理论值进行了比较。仿真结果与理论分析相吻合,说明了该模型的有效性和普适性。 相似文献
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广义K分布(GK-pdf)模型,是一种适用于宽带雷达杂波仿真的分布模型。文中首先研究了广义K分布模型及其统计特性,得到了相关系数之间的非线性关系。从而利用零记忆非线性变换(ZMNL)方法仿真了相关广义K分布杂波,给出了基于ZMNL法的相关广义K分布杂波序列仿真原理和算法流程图,并仿真了几种经典的特殊广义K分布。仿真结果表明了该方法的有效性、准确性。 相似文献
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先验信息的使用可以提高知识辅助检测器的探测性能,若先验信息与当前探测环境不匹配,检测器性能可能会受到影响。该文考虑一种复合高斯杂波下的知识辅助检测器,其采用逆伽马分布作为纹理分量先验分布,分析该检测器在不同杂波纹理分量模型参数条件下的检测性能。首先给出了先验模型参数失配条件下,虚警概率和Swerling I型目标检测概率的计算方法。然后在给定先验模型参数条件下,分析了杂波纹理分量分布参数对检测器性能的影响。理论分析表明,若杂波纹理分量分布参数位于某个区域以内时,检测器可以获得比模型匹配时更好的检测性能,计算机仿真验证了上述结论。 相似文献
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为了获取较高的宽带信号的DOA(direction-of-arrival)估计精度,提出了基于改进的广义回归神经网络(IGRNN,improved generalized regression neural network)和主成分分析(PCA,principalcomponent analysis)的宽带DOA估计算法。选用PCA方法对训练样本进行降维,以降低神经网络的复杂度;利用粒子群算法优化GRNN的参数;根据选取不同的聚焦角度确定粗估计、精估计的训练模型,通过粗估计得出目标的大致方位后,利用精估计模型得出最终的估计结果,避免了聚焦角度对估计精度的影响。仿真结果表明,本文提出的算法具有较好的估计精度和较高的工作效率。 相似文献
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Automatic Estimation of Multiple Target Positions and Velocities Using Passive TDOA Measurements of Transients 总被引:3,自引:0,他引:3
Dragana Carevic 《Signal Processing, IEEE Transactions on》2007,55(2):424-436
This paper considers the problem of the estimation of the motion parameters of multiple targets moving linearly in a three-dimensional (3-D) observation area contaminated by clutter. The measurements are limited to time differences of arrival (TDOAs) of short-duration acoustic emissions, or transients, generated by the targets. This problem can arise in situations where the level of continuous broadband target-related noise is very low. Owing to the fact that transient emissions are nonstationary and can have low signal-to-noise ratio (SNR), the corresponding TDOA measurement errors are usually non-Gaussian. Therefore, Gaussian mixture distributions are used to appropriately model these errors. An iterative maximum-likelihood optimization technique based on a modified deterministic annealing expectation-maximization (MDAEM) algorithm is applied to this problem. In each iteration, the algorithm uses a nonlinear least-squares (LS) technique in computing the motion parameters for each target. It generalizes the variance deflation method previously used for the initialization of target tracking algorithms and increases the possibility of attaining a globally optimal solution for random initial conditions. Simulation results are presented for several different numbers of targets, clutter densities, and probabilities of gross error of the target related measurements and are found to be comparable to the estimates obtained when the measurement-to-target assignments are exactly known 相似文献
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Parametric modeling and estimation of complex valued homogeneous random fields with mixed spectral distributions is a fundamental problem in two-dimensional (2-D) signal processing. The parametric model under consideration results from the 2-D Wold-type decomposition of the random field. The same model naturally arises as the physical model in problems of space-time adaptive processing of airborne radar. A computationally efficient algorithm for estimating the parameters of the field components is presented. The algorithm is based on a nonlinear operator that uniquely maps each evanescent component to a single exponential. The exponential's spatial frequency is a function of the spectral support parameters of the evanescent component. Hence, employing this operator, the problem of estimating the spectral support parameters of an evanescent field is replaced by the simpler problem of estimating the spatial frequency of a 2-D exponential. The properties of the operator are analyzed. The algorithm performance is illustrated and investigated using Monte Carlo simulations 相似文献
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研究了非高斯K分布杂波条件下雷达目标散射中心参数估计问题,提出一种基于协同粒子群优化(CPSO Coop- erative-Particle Swarm Optimization)算法的M估计方法。针对K分布杂波的非高斯尖峰特性,首先利用M估计中的损失函数构造出散射中心参数估计的目标优化函数,然后利用协同粒子群算法,通过迭代优化得到目标的散射中心参数。该方法能够同时得到散射中心幅度和位置的稳健估计,通过与基于子空间的估计方法进行仿真实验对比,结果表明,在K分布杂波条件下该方法能够的得到更好的估计结果。 相似文献
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认知雷达波形设计往往依赖于精准的杂波先验信息,当先验信息数据存在缺失时,所构建的杂波模型会严重失配,进而影响雷达对杂波的抑制能力。该文针对杂波先验数据缺失条件下的雷达波形优化问题,建立完全随机缺失机制下的点状与块状缺失场景,设计恒模与相似性约束的波形优化模型,提出基于优先级填充-强化学习级联优化的雷达波形训练算法:即采用强化学习智能体与填充算法修复后的杂波环境相交互的级联方法,以最大化信杂噪比为优化目标,通过迭代训练得到雷达最佳波形参数配置策略。最后,仿真验证不同缺失概率条件下所提算法的优越性。结果表明:相比于传统非级联优化算法,该文所提算法均可获得更优的杂波抑制性能,有效提升雷达的探测能力。 相似文献