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针对单站无源定位可观测性弱、观测噪声大而导致的定位精度低、稳定性差和收敛速度慢等问题,在结合平方根无迹卡尔曼滤波(Square-Root Unscented Kalman Filter,SRUKF)以及后向平滑思想的基础上,提出了一种改进SRUKF的双向滤波算法。该算法采用Q-R分解的形式,使用误差协方差的平方根代替协方差参与递推运算,提高了算法的稳定性与运算效率。同时,该算法对状态向量进行扩维,将过程噪声与观测噪声通过非线性系统传播,降低了噪声对滤波精度的影响,并利用当前时刻滤波结果通过Rauch-Tung-Striebel(RTS)后向平滑得到再次前向滤波更高精度的起始值,提高了算法的定位精度与收敛速度。仿真结果表明,新算法在保证实时性的基础上改善了单站无源定位的性能。 相似文献
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Chen and Bhattacharyya [Exact confidence bounds for an exponential parameter under hybrid censoring, Commun Statist Theory Methods 17 (1988), 1857–1870] considered a hybrid censoring scheme and obtained the exact distribution of the maximum likelihood estimator of the mean of an exponential distribution along with an exact lower confidence bound. Childs et al. [Exact likelihood inference based on Type‐I and Type‐II hybrid censored samples from the exponential distribution, Ann Inst Statist Math 55 (2003), 319–330] recently derived an alternative simpler expression for the distribution of the MLE. These authors also proposed a new hybrid censoring scheme and derived similar results for the exponential model. In this paper, we propose two generalized hybrid censoring schemes which have some advantages over the hybrid censoring schemes already discussed in the literature. We then derive the exact distribution of the maximum likelihood estimator as well as exact confidence intervals for the mean of the exponential distribution under these generalized hybrid censoring schemes. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004 相似文献
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MUSIC算法能对独立信号的波达方向(DOA)进行有效估计,但该算法对相干信号或强相关信号进行DOA估计时,算法性能会随着相关系数的增加而急剧恶化甚至失效.针对该问题,利用前后向空间平滑技术与修正MU—SIC算法进行去相关,研究了它们去相关的基本原理及优缺点;利用MUSIC算法通过实验仿真对相关信号的波达方向估计性能进行了研究,分析了信号间相关系数对前后向空间平滑算法与修正MUSIC算法的测向性能的影响,并验证了算法去相关的有效性. 相似文献
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曹喜望 《国防科技大学学报》2012,34(2):39-41
置换多项式一直是一个热门的研究课题,事实上,研究有限域上的置换多项式相当于研究有限域上的一一映射.所以它在编码密码、组合设计、代数曲线等许多领域有重要的应用.Carlitz曾经对一些置换多项式有一个刻画,证明了如果f(x)是一个系数在F0的多项式满足f(0)=0,f(1)=l,并且对任意a,b ∈Fq有η(f(a)-f(b))=η(a-b),这里η是Fq的乘法群Fq*的二次特征,则存在某个非负整数j使得对任意χ ∈F0,有f(x)=xpj.本文给出了这个结果的推广. 相似文献
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一种自适应指数加权衰减记忆滤波算法 总被引:4,自引:0,他引:4
根据衰减记忆因子为一个常数的不尽合理性的假设,深入研究了指数加权衰减记忆滤波因子,根据滤波收敛条件和滤波模型准确时的新息(残差)特点,提出了具有自适应性、抑制滤波发散的指数加权衰减记忆滤波算法,并通过仿真试验验证了自适应抑制滤波发散的有效性。 相似文献
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This paper analyses the financial and war‐spending policies of a state that faces a conflict in which defeat would result in the loss of sovereign power and in which the material consequences, conditional on avoiding defeat, are stochastic. The analysis takes explicit account of the historical experiences of lenders, who face debt repudiation if the state to whom they have lent is defeated and who also face partial default if the material consequences of the war are unfavorable for the debtor state, even if it avoids defeat. In this analysis, the state uses war debt to smooth expected consumption intertemporally in response to temporary war spending, and the state also uses contingent debt servicing to insure realized consumption against the risk associated with the material consequences of the war. An important innovation in the analysis is to treat the equilibrium amount of war spending, the state's resulting probability of avoiding defeat, as well as the equilibrium amount of borrowing as a set of endogenous variables to be determined simultaneously. 相似文献