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本文在Andrisani等人近年来工作的基础下,进一步发展了线性离散随机系统的多级分解估计方法,提出了比较完善的多级分解预测与滤波公式,并将本文的工作与Andrisani等人的工作作了比较。本文给出的预测与滤波算法计算量较小,便于实时处理,且估算精度与集中估计方法基本一致。文中给出了应用算例,分析了模型误差对预测和滤波结果的影响。 相似文献
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基于惯性/卫星(全球卫星定位系统(GPS)/北斗双星)/多普勒/星光组合导航系统,提出了一种用于组合导航系统的多传感器分层多级变结构部分优化故障检测、隔离与系统重构(FDIR)的信息融合模型和算法。给出了模型的构成,并讨论了分层多级融合顺序与部分融合对全局估计的影响及其优化。理论分析和仿真试验结果表明,分层多级部分优化融合模型融合后的综合性能优于联邦滤波基本融合模型。 相似文献
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针对超常规叶轮机械——对转压气机采用5种定常叶排交界面方法,结合实验值对比分析了对转压气机整机性能、近设计工况以及近失速工况流场,以定量研究不同交界面方法应用于叶排交界面的参数传递效果.结果表明:①不同交界面方法计算的整机效率性能差异明显,而压比性能与实验值吻合较好.②近设计工况下,周向守恒法在不同交界面的参数传递连续性相对较好,当地守恒法和完全非匹配混合界面法对下游界面参数的控制作用逐渐增强,一维无反射边界条件和完全非匹配冻结转子法则正好相反.③近失速工况下,一维无反射边界条件和完全非匹配冻结转子法对应的叶片前缘高熵损失区范围明显增大,叶顶主流和间隙溢流交界面扭曲成更靠近上游叶排交界面的弧形. 相似文献
将乘波体作为以吸气式超燃冲压发动机为动力的高超声速飞行器的前体,不仅可以发挥乘波体优异的气动力性能,而且起到了高超声速飞行器前体对来流的预压缩作用.为了进一步提升乘波前体的预压缩作用,基于Sobieczky提出的吻切锥原理,发展了一种新的多级压缩乘波体外形的设计方法.将该设计方法应用到锥导和吻切锥乘波体的设计中,生成了具有多个压缩面的多级压缩锥导和吻切锥乘波体,同时对相同设计条件和具有相同投影曲线的前缘条件下获得的三级压缩锥导和吻切锥乘波体的性能进行了对比分析.研究结果表明数值模拟计算结果与设计预期完全吻合,该多级压缩乘波体设计方法可以应用于锥导和吻切锥乘波体. 相似文献
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Xingzhi Hu Xiaoqian Chen Yong Zhao Wen Yao 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
The separation systems are crucial for the launch of satellites. With respect to the existing design issues of satellite separation systems, an optimization design approach based on Multi-Island Genetic Algorithm is proposed, and a hierarchical optimization of system mass and separation angular velocity is designed. Multi-Island Genetic Algorithm is studied for the problem and the optimization parameters are discussed. Dynamic analysis of ADAMS used to validate the designs is integrated with iSIGHT. Then the optimization method is employed for a typical problem using the helical compression spring mechanism, and the corresponding objective functions are derived. It turns out that the mass of compression spring catapult is decreased by 30.7% after optimization and the angular velocity can be minimized considering spring stiffness errors. Moreover, ground tests and on-orbit flight indicate that the error of separation speed is controlled within 1% and the angular velocity is reduced by nearly 90%, which proves the design result and the optimization approach. 相似文献
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针对在某些通信系统中对译码速度较高的需求,基于分组编码调制(BCM,Block Coding Modulation)的多级结构,给出了一种多级BCM的多阶段译码算法:从BCM中第一级分量码开始,根据BCM的级数逐阶段进行译码,针对每级分量码,采用软判决最大似然译码,直到最后一级分量码,从而降低了译码复杂度.仿真结果表明,与传统Viterbi译码算法相比,提出的多阶段译码算法的误码性能与其相当,信噪比较小时甚至更好,但译码复杂度远低于传统Viterbi译码方法. 相似文献
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Abdu Mohammed Seid Tesfahun Berhane Lassi Roininen Melessew Nigussie 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(5):1193-1205
We model regular and irregular variation of ionospheric total electron content as stationary and non-stationary processes, respectively. We apply the method developed to SCINDA GPS data set observed at Bahir Dar, Ethiopia . We use hierarchical Bayesian inversion with Gaussian Markov random process priors, and we model the prior parameters in the hyperprior. We use Matérn priors via stochastic partial differential equations, and use scaled hyperpriors for the hyperparameters. For drawing posterior estimates, we use Markov Chain Monte Carlo methods: Gibbs sampling and Metropolis-within-Gibbs for parameter and hyperparameter estimations, respectively. This allows us to quantify model parameter estimation uncertainties as well. We demonstrate the applicability of the method proposed using a synthetic test case. Finally, we apply the method to real GPS data set, which we decompose to regular and irregular variation components. The result shows that the approach can be used as an accurate ionospheric disturbance characterization technique that quantifies the total electron content variability with corresponding error uncertainties. 相似文献