基于切比雪夫神经网络的软件定义卫星网络智能路由策略

针对现有的软件定义卫星网络中流表占用的三态内容寻址存储器空间不断增加,复杂的流表项查找、匹配过程导致路由转发效率降低,无法满足多样化应用需求的问题,提出基于神经网络的软件定义卫星网络智能路由架构。控制器通过训练神经网络获取数据流的传输模式,并用训练后的神经网络代替流表,在此基础上提出基于Chebyshev神经网络的智能路由策略,交换机根据数据流的业务类型预测其转发路径,以满足卫星网络应用的服务质量要求。仿真结果表明:所提路由策略显著减少了占用的三态内容寻址存储器存储空间,提高了路由效率。     

The Environment as a Factor in Small Wars*

This research paper analyzes the relationship between small wars, insurgency, and the natural environment. Existing literature and data are organized into four behavioral patterns: the resource-based wars accounts for the fight over natural resources; the warfare ecology paradigm refers to non-premeditated damage in preparation for as well as during and after conflicts; the environment as a target discusses intended attacks on the ecosystem; and the insurgency–climate intersection pattern denotes a deviation in climate change that increases the frequency of intergroup violence. The main premise is that small wars emerge when the ecosystem becomes a political asset.     

融合地面多传感器信息引导无人机着陆

针对无人机自主着陆过程中卫星导航系统易被干扰的问题,提出了一种基于地基多传感器融合的无人机自主着陆引导方法。采用主动式激光照射的方式,获取机载反射棱镜的近红外成像,在红外图像中对无人机目标进行识别;通过坐标转换将识别结果映射到可见光图像中,在可见光图像中选择的感兴趣区域进行可见光目标识别,从而在降低计算量的基础上获得更加精确的无人机相对角度信息;利用距离测量信息和引导系统角度信息可以获得精确的无人机相对位置。无人机着陆引导试验结果表明,该方法能够提供精确的无人机位置信息,能有效适应于复杂背景下的无人机自主着陆引导。     

Statistical Analysis as an Adjunct to Historical Research: Identification of the Likely Manufacturers of British Pattern 1907 Bayonets Supplied by the Birmingham Small Arms Company to the Siamese Government in 1920

In 1920, the Birmingham Small Arms Company supplied 10,000 Pattern 1907 bayonets to the government of Siam to accompany an order for rifles. The original maker of these bayonets was unknown, but historical research indicates that the Wilkinson Sword Co. Ltd. was a primary maker. The weights of some surviving Pattern 1907 bayonets, including twelve bayonets from the 10,000 described above, produced by the six makers in the UK before and during the Great War (1914–1918) period were available. A statistical analysis of the data was performed to compare with the historical research. The results strongly supported that the Wilkinson Sword Co. Ltd. was a primary maker. They were also sufficient to exclude from this batch of twelve bayonets the Royal Small Arms Factory (Enfield) and Vickers Ltd. as manufacturers. The statistical evidence for the presence of bayonets made by J.A. Chapman Ltd., R. Mole & Sons and Sanderson Bros. was weaker than that for the Wilkinson Sword Co. Ltd., but was nevertheless supportive of that hypothesis. Overall, the analysis was consistent with the supply to Siam of commingled bayonets from British government stores. It was noted that the bayonets for the Siam contract fell into a relatively narrow weight range, but the reason for this could not be determined.     

卫星导航系统定位精度估计

系统精度估计是卫星导航系统总体设计的重要环节,是进行大系统指标分配的重要依据.因此.在进行卫星导航系统总体设计时,必须对所有误差源的特性及其对系统精度的影响情况进行仔细的仿真计算分析.采用对定位测量方程进行全微分的方法,导出了卫星导航系统定位精度的协方差估计公式,给出了用于指导工程实际对关键误差源进行严格控制的一整套理论和方法.     

带数据传输的光学卫星成像调度系统关键技术研究

针对光学小卫星成像调度系统设计需求,考虑侧视、存储容量、能量和数据传输等复杂约束,面向小规模问题应用,设计了问题求解流程.建立了顶点和边都带权的成像约束图模型,并提出了基于标记更新最短路算法的复杂约束成像卫星调度算法解决成像方案生成过程;对数传方案生成过程,给出背包模型并采用带回看策略的贪婪启发式方法进行问题求解.实验结果表明,该方法是可行和适用的.     

主星带伴随分布式小卫星雷达系统的波束同步分析

波束同步是主星带伴随分布式小卫星雷达系统的同步问题之一,分析了主星带伴随分布式小卫星雷达系统的波束同步问题。根据主星带伴随分布式小卫星雷达系统的特点,结合小卫星天线俯仰向可扫描、姿态可调节,提出了三种波束指向同步方法;分析了分布式小卫星雷达系统的波束覆盖同步问题,分别建立了主星和伴随分布式小卫星的波束覆盖数学模型;仿真分析“干涉车轮”,结果不仅证明这些模型的正确性,同时发现波束指向同步方法2有较好的优越性。     

低轨移动卫星异步多用户检测算法

介绍了一种适合在低轨(LEO)星载接收机上运行、低复杂度的异步CDMA多用户检测算法,能够有效对抗强多用户干扰和大多普勒频移。基带信号通过码片滤波后以码速率采样信号作为观测信号,然后利用Kalman滤波算法对各个用户信号进行分离。状态方程综合考虑了多普勒频移、定时误差。该算法能够抵抗高达35dB的远近效应,并且对频率和定时误差不敏感。     

适应任务的模块化卫星快速构建优化决策方法

如何根据应急航天任务,在满足各种约束的前提下,从型号众多、能力各异的卫星平台及有效载荷中快速决策效费比最佳的卫星构造方案引起了越来越多的关注,这就是适应任务的模块化卫星快速构建优化决策问题.在深入分析该问题特点的基础上,建立优化决策数学模型,提出基于遗传算法的优化决策方法,为处理遗传算法迭代过程中产生的不可行解引入基于...     

卫星轨道Kalman滤波稳健估计

卫星观测数据中不可避免地存在着粗差 ,一般的Kalman滤波易受观测粗差的影响。首先推导Kalman滤波稳健估计公式 ,并分析了它的稳健性。然后用Kalman滤波稳健估计对Lageos卫星的激光实测资料进行了处理 ,证明它具有明显的抗粗差的能力和稳健性