共查询到20条相似文献,搜索用时 46 毫秒
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在SAR/INS组合导航系统中,所获取的SAR图像可能存在严重的斑点噪声和几何变形,对此,提出一种基于CenSurE特征的SAR/INS组合导航用景象匹配算法.该算法针对惯性组合导航的工作特点进行设计.首先提取CenSurE特征和垂直的SURF描述符,利用夹角余弦相似度量方法进行特征匹配;然后,采用分组一致采样算法和最小二乘精确匹配算法获取高精度的航向和位置偏差信息.景象匹配性能评价实验表明。在匹配适应性、匹配速度、精度和鲁棒性等方面,CenSurE特征都很优越,可以满足SAR/INS景象匹配导航系统匹配修正的高性能要求. 相似文献
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为了保证SINS/GPS组合导航系统具有较高的定位精度和抗干扰能力,需要良好的数据处理方法。论文设计了SINS/GPS组合导航系统的联合自适应卡尔曼滤波器。研究了其在舰船组合导航系统随机数据处理中的应用。针对系统噪声和量测噪声未知的情况,采用联合自适应滤波处理组合导航系统较采用基本联合Kalman滤波方法具有更好地稳定性。理论分析与仿真结果表明,该联合自适应卡尔曼滤波器的设计合理,能够加快计算速度,实现实时滤波计算,提高系统的导航精度和容错能力,取得了很好的估计效果。 相似文献
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天文-惯性组合导航技术在高空飞行器中的应用 总被引:2,自引:0,他引:2
综述了天文-惯性组合导航在高空飞行器中的应用和发展概况,在分析了国内外装载天文导航系统(CNS)/惯性导航系统(INS)的航空飞行器基础上,从工作环境、组合模式、导航解算等方面分析了CNS/INS的技术性能,指出CNS-INS组合导航更适用于执行长航时、高空飞行的航空飞机,能够满足航空飞行器对高精度导航系统的需要.概括了CNS/INS导航的特有优点,提出了发展CNS-INS组合导航的必要性,讨论了今后机载CNS-INS组合导航技术的研究发展方向. 相似文献
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北斗/GPS无人飞行器动态导航中改进自适应算法 总被引:1,自引:0,他引:1
《电子技术应用》2015,(10):58-61
北斗与GPS或其他类型导航设备可构成组合导航系统,为无人飞行器提供高精度、高可靠导航信息。在处理动态导航数据采用"当前"统计模型(CS模型)并利用标准Kalman滤波方法时,系统动态噪声和观测噪声未知且时变,而且加速度上下限值不能自适应于未知运动规律的无人飞行器当前加速度,导致导航精度降低。为此,提出一种适应于飞行器运动状态的改进自适应算法,并应用于北斗/GPS动态导航系统中。实验仿真验证了该算法能有效提高组合导航系统的精度和可靠性,并能更好地自适应于无人飞行器的机动特性。 相似文献
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J. MacGregor 《Performance Evaluation》2003,52(4):237-267
An exact solution for the M/G/c/K model is only possible for special cases, such as exponential service, a single server, or no waiting room at all. Instead of basing the approximation on an infinite capacity queue as is often the case, an approximation based on a closed-form expression derivable from the finite capacity exponential queue is presented. Properties of the closed-form expression along with its use in approximating the blocking probability of M/G/c/K systems are discussed. Extensive experiments are provided to test and verify the efficacy of our approximate results. 相似文献
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Roger W Hockney 《Parallel Computing》1985,2(1):1-14
We report performance measurements made on the 2-CPU CRAY X-MP at ECMWF, Reading. Vector (SIMD) performance on one CPU is interpreted by the two parameters (), and we find for dyadic operations using FORTRAN . All vector triadic operations produce ; and a triadic operation with two vectors and one scalar gives r∞ = 148 Mflop/s and . MIMD performance using both CPUs on one job is interpreted with the two parameters (), where is the amount of arithmetic that could have been done during the time taken to synchronize the two CPUs. We find, for dyadic operations using the TSKSTART and TSKWAIT synchronization primitives, that r∞ = 130 Mflop/s and . This means that a job must contain more than ~ 6000 floating-point operations if it is to run at more than 50% of the maximum performance when split between both CPUs by this method. Less expensive synchronization methods using LOCKS and EVENTS reduces to 4000 flop and 2000 flop respectively. A simplified form of LOCK synchronization written in CAL code further reduces to 220 flop. This is probably the minimum possible value for synchronization overhead on the CRAY X-MP. 相似文献
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Consideration was given to the discrete-time queuing system with inversive servicing without interrupts, second-order geometrical
arrivals, arbitrary (discrete) distribution of the customer length, and finite buffer. Each arriving customer has length and
random volume. The total volume of the customers sojourning in the system is bounded by some value. Formulas of the stationary
state probabilities and stationary distribution of the time of customer sojourn in the system were established. 相似文献
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Kazuko Morizawa Hiroyuki Nagasawa Noriyuki Nishiyama 《Computers & Industrial Engineering》1994,27(1-4):23-26
“Complex Random Sample Scheduling(CRSS)” was proposed in this paper as an efficient heuristic method for solving any permutation scheduling problems. To show the effectiveness of the proposed CRSS, it was applied to an N-job, M-machine, permutation flowshop scheduling problem to minimize makespan, N/M/F/Fmax. Numerical experiments made it clear that the proposed CRSS provides a schedule very close to the near-optimal schedule obtained by the existing promising heuristic methods such as taboo search and simulated annealing, within less computation time than these heuristic methods. 相似文献
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T. C. E. Cheng 《Computers & Industrial Engineering》1992,22(4):495-499
Several efficient algorithms of O(n log n) computational complexity, for the Johnson's rule to schedule a set of simultaneously available jobs on two machines in a flowship to minimize the maximum job flowtime have appeared in the literature. A modified version of one of these algorithms is presented which not only simplifies the programming effort for implementation but is also able to generate all possible optimal sequences obtainable from Johnson's rule. 相似文献
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H.G. Perros 《Performance Evaluation》1983,3(2):83-93
We obtain the exact analytic expression of the probability distribution of the number of units in a single server queue with Poisson arrivals and Coxian service time distribution (notated as M/Ck/1). A recursive procedure for calculating this probability distribution is given. The well-known queues M/Ek/1 and M/D/1 are re-derived as special cases of the M/Ck/1 queue. Finally, the cases of M/C2/1 and M/C3/1 are fully worked out. 相似文献
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Finite buffer, single-server queueing systems and networks are difficult to analyze since the length of time a customer spends in the system does not follow the Markovian property. A two-moment approximation schema is developed for the probability distribution of M/G/1/K systems and extended to the analysis of M/G/1/K queueing networks. The general purpose of this paper is to develop a flexible and practical transform-free approach for computing the probability distribution and performance measures of the system as well as identify the underlying properties of these systems. It is shown that for most performance measures, a sigmoid or S-shaped curve with an inflection point at ρ=1 appears as K→∞. This has direct implications for the analysis and optimization of such systems. The performance modelling of the M/G/1/K queueing networks of general topologies along with extensive numerical results accompany the paper along with the linear concave performance measures for these systems. 相似文献