共查询到18条相似文献,搜索用时 156 毫秒
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针对信道编码参数的盲估计问题,提出了一种k/n卷积码参数盲估计的鲁棒性方法.首先,将卷积码的参数估计问题转换为求解二元域上线性方程组的问题,然后,应用Walsh-Hadamard变换对该问题求解,设计了卷积码编码参数的估计算法,并对算法中的门限选取进行了分析.仿真实验表明,相较于现有的算法,本文提出的方法具有更好的抗噪性能,在信道传输的错误率小于等于0.07时,本文方法对不同编码器参数的识别正确率均达到了95%以上. 相似文献
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用广义radon变换可以从运动目标产生的干涉条纹中估计出目标的运动参数和波导不变量。但是当干涉条纹中没有出现临近点时,用此方法估计不出真实值。为了解决此问题,提出了一种新的估计方法。主要过程是先从时频图中提取出干涉条纹轨迹,再去搜索与此轨迹误差最小的最优曲线,此曲线的参数值代表目标的运动参数和波导不变量。仿真和海试结果表明,在干涉条纹无临近点信息情况下,用广义radon变换估计的参数值与真实值偏差很大,但是文中提出的方法仍能估计出较准确的结果。 相似文献
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文章针对MIMO-OFDM系统中的信道估计关键技术提出了一种信道估算方法—基于线性非冗余预编码和二阶统计量的信道盲估计算法,该算法利用预编码信号的二阶统计特性消除了调制信号的信息,然后又利用STBC(Space-Time Block Coding空时分组编码)特殊的复正交特性对参考子载波信道矩阵进行变换,将求逆过程转换成简单的线性处理过程,从而实现了低复杂度的信道估计。另外,该算法通过选取合适长度的统计数据,能够较快收敛。 相似文献
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提出了一种基于单比特量化的单频信号自适应时延估计算法,采用该算法在保持信号频谱特性不发生变化的基础上,极大地去除信号冗余量,对简化后的信号框架采用包络检测,估计时延.对接收信号进行单比特量化能够最大限度地降低数据量,同时量化结果又进一步简化了单频信号滤波器的输入响应函数结构,自适应算法则保证了时延估计的高分辨率.通过仿真实验表明,该算法在不造成频偏和频率衰减的同时,又很好保证了时延估计精度.最后利用湖上实验验证了算法的有效性和可靠性. 相似文献
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单静止站纯方位被动声纳系统是不完全可观测系统,关于该类系统的既往研究表明,对于匀速直线运动的目标,利用目标方位角信息可以估计出目标的航向,这具有重要的实际应用意义.通过对目标运动几何模型分析,推导得到目标方位角与目标航向的关系公式,并提出依据几何关系的目标航向估计算法.通过进行坐标变换引入最小二乘估计思想,提高了估计方法的有效性.使用Monte-Carlo计算机仿真测试了算法在不同目标方位角和不同数据长度下的性能,并与拟线性递推法和递推最小二乘法进行了比较,结果表明该算法具有更高的估计精度和更好的适应性. 相似文献
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基于边界强度的Hausdorff距离及其在目标定位中的应用 总被引:1,自引:0,他引:1
目标定位是机器视觉领域的重要问题.针对传统方法受背景干扰点影响较为严重的问题,提出一种基于边界强度的改进型Hausdorff距离用于目标定位.该方法在边界提取算法的基础上,利用边界长度、边界梯度和边界闭合度计算目标图像所提取边界的权值,并结合加权Hausdorff距离建立定位匹配函数.为避免定位寻优过程陷入局部极小点,采用多变量相关的分布估计算法,利用概率模型描述匹配参数之间的相互关系,并以此模型产生优势样本,实现多维目标的准确定位.实验表明,该方法在目标定位的精确性和快速性方面都要优于传统算法. 相似文献
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基于提高声场水平纵向相关的频移补偿方法,提出了一种声场波导不变量的计算方法。该方法简单易行,只需处理具有一定纵向间隔的两个水听器接收的信号。该方法通过将波导不变量设定在一定范围内进行搜索,最终选取波导不变量的值为使两个水听器所接收声信号的经频移补偿后的空间相关系数取最大值时对应的数值。浅海声学实验结果表明,利用该方法能实现声场波导不变量的准确估算。实验结果中所得出的波导不变量值随频率的变化特性及相应的理论分析都表明,在频率较低时频率对浅海声场波导不变量的取值有一定影响,因此波导不变量并不是不变的。 相似文献
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Modeling and state of charge(SOC) estimation of lithium-ion(Li-ion) battery are the key techniques of battery pack management system(BMS) and critical to its reliability and safety operation.An auto-regressive with exogenous input(ARX) model is derived from RC equivalent circuit model(ECM) due to the discrete-time characteristics of BMS.For the time-varying environmental factors and the actual battery operating conditions,a variable forgetting factor recursive least square(VFFRLS)algorithm is adopted as an adaptive parameter identification method.Based on the designed model,an SOC estimator using cubature Kalman filter(CKF) algorithm is then employed to improve estimation performance and guarantee numerical stability in the computational procedure.In the battery tests,experimental results show that CKF SOC estimator has a more accuracy estimation than extended Kalman filter(EKF) algorithm,which is widely used for Li-ion battery SOC estimation,and the maximum estimation error is about 2.3%. 相似文献
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Quantitative analyses of biological networks such as key biological parameter estimation necessarily call for the use of graphical models. While biological networks with feedback loops are common in reality, the development of graphical model methods and tools that are capable of dealing with feedback loops is still in its infancy. Particularly, inadequate attention has been paid to the parameter identifiability problem for biological networks with feedback loops such that unreliable or even misleading parameter estimates may be obtained. In this study, the structural identifiability analysis problem of time‐invariant linear structural equation models (SEMs) with feedback loops is addressed, resulting in a general and efficient solution. The key idea is to combine Mason''s gain with Wright''s path coefficient method to generate identifiability equations, from which identifiability matrices are then derived to examine the structural identifiability of every single unknown parameter. The proposed method does not involve symbolic or expensive numerical computations, and is applicable to a broad range of time‐invariant linear SEMs with or without explicit latent variables, presenting a remarkable breakthrough in terms of generality. Finally, a subnetwork structure of the C. elegans neural network is used to illustrate the application of the authors’ method in practice.Inspec keywords: matrix algebra, least squares approximations, statistical analysis, parameter estimation, biologyOther keywords: structural identifiability analysis problem, time‐invariant linear structural equation models, feedback loops, identifiability equations, time‐invariant linear SEMs, time‐invariant biological networks, graphical model methods, parameter identifiability problem, biological parameter estimation, subnetwork structure, C. elegans neural network 相似文献
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基于周期统计平均的结构动力复合反演研究 总被引:3,自引:0,他引:3
研究了输入未确知条件下的参数识别、荷载反演问题。根据激励的周期特性,运用统计平均的思想,构造出一类时域识别反演算法。数值算例表明,该算法的参数识别精度高,且具有很强的噪声适应能力和初参数选择鲁捧性。将本算法与全量补偿算法有机会结合,可更好地解决在旋转动力设备周期激振力作用下的结构参数识别及荷载反演问题。 相似文献
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ESPRIT (estimation of signal parameters via rotational invariance techniques) is a recently introduced algorithm for narrowband
direction-of-arrival (DOA) estimation. Its principal advantage is that the DOA parameter estimates are obtained directly,
without knowledge (and hence storage) of the array manifold and without computation or search of some spectral measure. This
advantage is achieved by constraining the sensor array to be composed of two identical, translationally invariant subarrays.
In this paper, we analyse the sensitivity of ESPRIT to the assumption that the subarrays are identical. The analysis is applicable
to a wide variety of array errors, including non-identical angle-dependent and angle-independent gain and phase perturbations, errors in the locations of the subarray elements, and mutual coupling effects. A representative
simulation example will be presented to validate the analysis and compare the performance degradation of ESPRIT with that
of the MUSIC algorithm. 相似文献
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一种抗几何攻击的小波域水印算法 总被引:6,自引:6,他引:0
目的针对小波变换域数字水印算法抗几何攻击能力差的问题,提出一种基于SIFT特征点匹配的DWT数字水印算法。方法将SIFT算法提取匹配特征点所具有的旋转、缩放和平移不变性的特性与DWT水印算法相结合,根据SIFT特征点的尺度特征和坐标关系,实现带水印图像的几何攻击参数估计和校正。结果仿真结果表明:提出的水印算法在受到系列旋转、缩放和平移攻击及组合攻击后,提取水印的NC值均大于0.8394,说明了算法的可行性。尤其是对于抗旋转攻击,优于其他同类或相关算法。结论提出的算法对旋转、缩放、平移等3种几何攻击都具有较好的鲁棒性。 相似文献
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An optimal design method for a low broadband silica-on-silicon Y branc is considered. A multimode waveguide section, which was used earlier to reduce the excess loss, is designed optimally when the light distribution at the end of the multimode waveguide section is matched to the profile of the symmetric supermode for the structure of the two branching waveguides. An optimization method that combines the genetic algorithm and a gradient-based search method is used to obtain the optimal geometrical parameters for the multimode waveguide section as well as the widths for the input and branching waveguides. 相似文献