共查询到20条相似文献,搜索用时 15 毫秒
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运用建模的技术对导弹平台测试系统进行模型设计过程中,关键是实现测试系统需求描述模型、结构模型和行为模型等的设计;首先对导弹平台测试系统的工作流程进行了分析,然后在此基础上利用UML建模方法进行测试系统的各项模型设计,通过分解用例图说明测试系统的需求描述模型,分析系统的结构体系及关联关系建立了测试系统的结构模型,运用序列图建立了测试系统的行为描述模型;最后,根据上述模型设计提出了系统的结构及布置关系的设计方案,并且在实际导弹平台测试系统开发中得到了应用,实现了测试系统的各项测试功能;结果表明,采用该建模方法不但能够有效提高系统设计的效率,而且系统在实用性的基础上,还具有复用性及拓展性。 相似文献
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三次位相板编码系统的频率信噪比分析 总被引:1,自引:1,他引:0
建立了一个基于新型光学/数字成像系统(三次位相板编码系统—CPP系统)的信噪比模型.该模型主要考虑了读出噪音及散粒噪音两种探测器噪音,同时加入光学系统调制传递函数(Modulation Transfer Function,MTF)的影响,考虑不同空间频率下噪音对信号的影响,推导出频率信噪比模型.利用该模型对一个光学/数字成像系统进行信噪比分析,结果表明,利用该模型进行分析后此光学系统可达到的理论焦深扩展范围为5个波长. 相似文献
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激光雷达系统的数值仿真 总被引:10,自引:9,他引:1
为了对成像激光雷达系统进行性能分析,建立了成像激光雷达系统的数值仿真模型.模型以激光雷达原理为基础,考虑了激光雷达距离方程、噪声模型、接收信噪比、成像模型等模块,寻找不同环境与各模型参数的对应关系,以此预测环境对激光雷达系统性能的影响.根据模型,编制计算机仿真软件进行雷达系统模拟,结果表明,数值仿真有助于实验系统的方案设计和性能改进. 相似文献
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基于红外鱼眼探测系统的运动目标模型 总被引:2,自引:0,他引:2
建立了适用于红外鱼眼系统的目标运动模型,在不影响精度的前提下减少计算量是达到实时稳定地跟踪红外目标的途径之一。分析了目标在该系统成像的运动特性,结合系统帧频采样率较高的特点,提出了一种改进的匀速运动模型,并从理论上与"当前"统计模型的跟踪精度进行了对比分析。结果表明,在红外鱼眼系统采样率较高的情况下,匀速运动模型可以达到与"当前"统计模型相当的跟踪精度;利用卡尔曼滤波对模拟轨迹进行跟踪实验,验证了上述分析结果的正确性。该模型结构简单、运算量少,对于红外鱼眼系统下目标实时跟踪具有重要的意义。 相似文献
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针对传统基于正弦波磁光调制的方位失调角测量系统存在测量精度不高的问题,提出了一种新的系统方位失调角测量模型以提高系统测量精度。通过分析传统的基于正弦波磁光调制的方位失调角测量原理发现,由于采用省略高阶项的贝塞尔函数展开式表示磁光调制后的信号,引入了信号截断误差和方法误差,影响了系统测量精度。在分析基础上推导建立了一种基于纯三角函数表示的无理论误差的方位失调角测量新模型并进行了仿真。仿真结果表明,利用推导建立的失调角测量新模型,系统测量精度明显高于传统方法,这对重新理解基于正弦波磁光调制的方位失调角测量系统原理、提高系统测量精度具有一定的参考意义。 相似文献
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Jiying Huang Shengli Lin Xuewen Ma 《International Journal of Infrared and Millimeter Waves》2000,21(10):1603-1606
While the millimeter radio wave propagates through rainfall, it will be attenuated heavily due to assimilation and scattering of rain. It is imperative to establish a simple and effective model to predict the rain-induced attenuation. In this paper, the rainfall is taken as a random system that can attenuate the radio wave. The transfer function matrix model is selected to be the random system model. Using experiment rain attenuation data at different rain rate, the correlation entropy and residue error of the system is obtained by system identification method. On the basis of correlation entropy and residue error, we can determine the order of the predication system. At last, the predication model that can forecast heavy rain attenuation by small rain attenuation is gotten by applying the least square method. The comparison shows that the discrepancy between the predication result of the obtained model and the experiment rain attenuation data is relatively minor. 相似文献
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A novel simulation theory and model system for multi-field coupling pipe-flow system 总被引:1,自引:0,他引:1
Due to the lack of a theoretical basis for multi-field coupling in many system-level models, a novel set of system-level basic equations for flow/heat transfer/combustion coupling is put forward. Then a finite volume model of quasi-1D transient flow field for multi-species compressible variable-cross-section pipe flow is established by discretising the basic equations on spatially staggered grids. Combining with the 2D axisymmetric model for pipe-wall temperature field and specific chemical reaction mechanisms, a finite volume model system is established; a set of specific calculation methods suitable for multi-field coupling system-level research is structured for various parameters in this model; specific modularisation simulation models can be further derived in accordance with specific structures of various typical components in a liquid propulsion system. This novel system can also be used to derive two sub-systems: a flow/heat transfer two-field coupling pipe-flow model system without chemical reaction and species diffusion; and a chemical equilibrium thermodynamic calculation-based multi-field coupling system. The applicability and accuracy of two sub-systems have been verified through a series of dynamic modelling and simulations in earlier studies. The validity of this system is verified in an air–hydrogen combustion sample system. The basic equations and the model system provide a unified universal theory and numerical system for modelling and simulation and even virtual testing of various pipeline systems. 相似文献
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ZHANG Duan-Ming SUN Fan YU Bo-Ming PAN Gui-Jun SUN Hong-Zhang YIN Yan-Ping LI Rui SU Xiang-Ying 《理论物理通讯》2006,45(2):293-296
A simplified Olami-Feder-Christensen model on a random network has been studied. We propose a new toppling rule — when there is an unstable site toppling, the energy of the site is redistributed to its nearest neighbors randomly not averagely. The simulation results indicate that the model displays self-organized criticality when the system is conservative, and the avalanche size probability distribution of the system
obeys finite size scaling. When the system is nonconservative, the model
does not display scaling behavior. Simulation results of our model with
different nearest neighbors q is also compared, which indicates that the
spatial topology does not alter the critical behavior of the system. 相似文献
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湍流大气光通信系统误码率分析与实验研究 总被引:2,自引:0,他引:2
自由空间光通信(FSO)系统的性能由于受大气湍流影响会产生剧烈波动。根据系统和大气参数评估系统差错性能的研究具有现实意义。以大气湍流信道和光电探测两个模型为基础,建立了FSO系统差错性能的数学仿真模型,提出了湍流条件下系统误码率计算公式。对仿真结果与弱湍流条件下获得的实验数据进行了比较,并依据此模型对光强起伏和背景噪声等因素的影响进行仿真。仿真结果表明,基于该模型的仿真结果与实验数据一致,光强起伏是引起系统性能波动的主要因素,最优判决阈值需根据实际大气条件进行调整。该模型可有效评估湍流条件下FSO系统性能,并为相关理论研究提供参考。 相似文献
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Stochastic resonance (SR) is used widely as a weak signal detection method by using noise in many fields. In order to improve the weak signal processing capability of SR, a novel composite multi-stable model is proposed, which is constructed by the joint of the tristable model and the Gaussian Potential (GP) model. The SR system based on this model is constructed and the signal-to-noise ratio (SNR) is regarded as the index to measure the SR effect. The differential brain storm optimization (DBSO) algorithm is used to optimize the system parameters collaboratively to achieve parameter-induced adaptive SR. The influences of the system parameters V and R and the noise intensity D on the output response of SR system are analyzed under Gaussian white noise and α stable noise environments, and the advantages of the composite multi-stable SR system over the traditional tristable system are verified. For different levels of weak signals, the output performances of SR systems based on composite multi-stable model, traditional tristable model, composite tristable model are compared and analyzed. The results prove that the proposed model has better performance. Meanwhile, the adaptive detection of the multiple high-frequency weak signal is realized using the composite multi-stable SR system. The simulation results show that the proposed system has strong weak signal processing capability and good immunity to noise types, which widens the application range of SR in practical engineering. 相似文献
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针对受多种因素影响的复杂道路交通系统问题,基于颗粒动力学理论,结合传统的Lighthill-WhithamRichards物理模型,建立道路交通系统的流体物理模型,采用无网格粒子与网格相结合的方法进行数值仿真,并应用于典型道路交通问题的求解.在新模型中,将车辆比拟为硬颗粒,车辆的跟车比拟为颗粒间的碰撞相互作用,已知道路情况对驾驶员操作车辆的影响比拟为流-粒两相系统中的外部流体驱动力作用,不同车道间车辆的影响比拟为颗粒间的黏性作用,从而在颗粒动力学理论的基础上,推导建立了道路交通系统拟流体模型;引入光滑离散颗粒流体动力学(SDPH)对车辆系统模型进行离散,建立"SDPH车辆"与真实车辆之间的一一对应关系,再结合有限体积方法,对道路交通构建的双流体模型进行求解,建立求解交通流体物理模型的新型仿真方法.最后,采用所建立的模型和方法对车辆汇入以及机非混合对交通系统的影响过程进行了数值仿真,所得结果与实测值符合较好,表明新的模型和方法有效性好、可靠性高,为道路交通问题的解决提供了一条全新的途径. 相似文献