共查询到20条相似文献,搜索用时 140 毫秒
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完好性是民航基于性能的导航(PBN)运行的关键性能要求,是导航安全性的重要支撑。北斗导航系统(BDS)/惯性导航系统(SINS)紧组合导航系统将SINS信息加入到完好性监视中,增加了冗余信息,通过多假设解分离算法进行故障卫星的检测与隔离,满足民航特定飞行阶段高完好性要求。论文利用BDS接收机接收到的BDS卫星数据,通过设置飞行轨迹,模拟卫星故障,对BDS/SINS组合导航系统的完好性算法进行测试验证。实验结果表明,基于多假设解分离方法的BDS/SINS紧组合导航系统可以较好地实现故障卫星的检测与隔离,保护限计算符合预期。 相似文献
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为了研究卫星信号失效对SINS/GPS松组合导航系统和紧组合导航系统导航性能的影响,在分析惯导系统误差方程的基础上,给出了基于卡尔曼滤波的松组合和紧组合数学模型,构建了两种组合方式的仿真平台。仿真结果显示,SINS/GPS紧组合导航系统的精度要明显优于松组合导航系统,且在卫星信号失效导致可见星数目少于4颗甚至仅有1颗时,SINS/GPS紧组合依然能够保持组合模式,并可提供高于单一惯性导航系统的导航精度,说明了SINS/GPS紧组合方式具有较高的精度和可靠性。 相似文献
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基于MEMS-SINS/GPS的组合导航系统设计 总被引:1,自引:1,他引:0
针对小型无人机导航系统低成本、微小型、高效性的特点,提出了基于捷联惯导(SINS)\卫星定位(GPS)的组合导航系统设计方案,深入研究了组合导航系统的关键技术;分析了MEMS传感器误差对导航系统的影响,建立了系统误差模型;采用利于工程实现的基于位置、速度误差作为状态向量,以松耦合方式进行集中式Kalman滤波,对SINS/GPS信息进行融合,避免了传统SINS系统状态模型非线性,滤波器设计困难的问题;最后对系统进行了仿真;仿真结果表明,该组合导航系统成功抑制了SINS系统的积累误差,提高了导航精度与可靠性,具有广阔的应用前景。 相似文献
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针对MINS/GPS组合导航系统的松耦合、紧耦合组合方案进行了讨论,借鉴国内外对紧耦合MINS/GPS组合模式的研究,分析了松耦合、紧耦合和超紧耦合MINS/GPS组合模式的构成和工作原理,通过理论分析建立了基于伪距差分的组合卡尔曼滤波模型.通过半实物仿真试验研究紧耦合MINS/GPS系统数据融合处理的特性. 相似文献
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为提高捷联惯导系统SINS和全球定位系统GPS的精度和可靠性,研究了SINS和GPS的原理,建立了SINS/GPS系统的状态方程和位置速度误差量测方程;并采用卡尔曼滤波算法实现了SINS/GPS的组合导航.Matlab仿真结果证明,采用Kalman滤波实现SINS/GPS组合导航,其精度得到大大提高;且采用SINS/GPS组合导航系统,克服了SINS惯性导航难以长时间独立工作的缺点,解决了GPS易失锁、难以实时控制的不足,保证了导航系统的实时性及较高的精度和可靠性. 相似文献
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针对静止与匀速运动状态下低成本SINS/GPS组合导航系统航向角可观性差的问题,采用磁强计与低成本SINS/GPS构成新的组合导航系统,以提高系统的航向精度.给出了完整的组合导航系统卡尔曼滤波模型,利用Simulink进行了仿真实验.仿真结果表明:在静止与匀速运动状态下,SINS/GPS组合导航系统航向角误差发散,而SINS/GPS/磁强计组合导航系统的航向角有效收敛.利用某型系统进行了静态实验,实验表明:在传感器精度较差的条件下,SINS/GPS/磁强计组合系统航向角仍可以有效收敛,收敛后姿态角误差标准差小于0.2.静态实验验证了该方法在实际应用中的有效性. 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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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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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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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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