北斗导航系统移动基准站差分定位算法

针对复杂测量环境无法建立固定基准站及进行精密定位的问题,提出一种基于北斗导航系统的移动基准站差分定位算法,即基准站与流动站同时运动并实现高精度差分定位的算法。基于载波相位测量值,在动态短基线条件下,对数据进行站间和星间双差处理,消除接收机钟差以及其他公共误差。对多频观测值进行线性组合,构造双差载波相位超宽巷、宽巷、中巷及窄巷观测量。对上述观测量进行窗口滑动均值滤波并采用逐级模糊度确定法固定整周模糊度,即沿着从超宽巷到窄巷的顺序依次求解整周模糊度。为验证算法有效性,设计基于北斗导航系统的轨道外部几何参数检测仪进行实验,实现毫米级静态相对定位精度和厘米级RTK相对定位精度。     

非线性干扰观测器的高超声速飞行器鲁棒反演控制

针对高超声速飞行器控制系统设计,提出一种基于干扰观测器的鲁棒反演控制器设计方法。采用反演控制方法分别设计速度和高度控制器。引入滑模微分器设计虚拟控制量的导数求解器,避免了传统反演控制"微分项膨胀"问题。为增强控制器的鲁棒性,设计一种非线性干扰观测器对模型不确定项进行自适应估计和补偿。通过数值仿真表明,该控制器能够保证对速度和高度参考输入的稳定跟踪。     

多帧高斯混合概率假设密度的多目标跟踪算法

针对低检测概率下多目标跟踪时,概率假设密度滤波器难以正确估计当前目标个数以及目标状态问题,提出一种基于多帧融合的高斯混合概率假设密度滤波算法。根据不同时刻目标权值构造目标多帧权值记录集及目标状态抽取标志。当某些时刻目标被漏检时,依据目标状态抽取标志,并结合目标多帧权值记录集中权值信息估计丢失目标的状态。仿真实验表明,算法有效地提高了低检测概率下现有相关算法的目标状态和数目估计精度。     

针对自适应滤波的组网雷达欺骗干扰优化策略

针对组网雷达系统在跟踪目标发生机动时采用自适应滤波来估计目标状态的特点,在点迹融合数据处理结构的组网雷达基础上提出了一种欺骗干扰优化策略.根据状态和量测方程描述了组网雷达跟踪目标的模型,同时建立了跟踪机动目标的自适应滤波模型.在此基础上,建立了欺骗干扰模型,并在目标机动检测约束下,推导了虚假目标欺骗干扰对于组网雷达融合...     

Why did Sudan Lose a small war in Southern Sudan?

ABSTRACT

When on the wrong end of an asymmetry in the projection of hard power, weaker sides countenance the grim arithmetic of avoiding direct and massed confrontations. Invariably, insurgents have over the ages tended to employ indirect tactical methods to render their stronger opponents ineffective. Ultimately – interest asymmetry, regime type, asymmetries of strategy, and external intervention – combine in a complex interplay and pattern, to militate against a strong side. In Sudan, these factors interacted throughout the civil wars to produce regional autonomy and finally an independent South Sudan in 2011. Similar strategic logic had confronted many large African states battling insurgencies in Ethiopia, Angola, Nigeria, Zaire, and apartheid-era South Africa. Oftentimes, weakening public resolve has caused these governments to accommodate, capitulate or withdraw even if they try not to blink. Notwithstanding the regime type, it can be concluded that the majority of strong actors are prone to fail in a protracted, asymmetric conflict. Hence, the notion of linking victory in counterinsurgency to the degree of openness (democratic polyarchies); or closeness (totalitarianism) – is still valid but highly contestable in the case of Africa’s large dysfunctional states.     

Maintaining peace in a neighbourhood torn by separatism: the case of Satun province in southern Thailand

While separatist-related conflict has re-emerged in southern Thailand, there is one predominantly Muslim border province that has remained outside of the conflict. Satun province has been conspicuously unaffected by the Malay-Muslim separatist movement, despite its shared history and ethnic origins with the conflict-affected provinces. In contrast to Pattani, Yala, and Narathiwat, the process of state penetration in Satun was gradual and comparatively less coercive, leading to relative stability and encouraging political and economic integration. This comparative study analyzes the history of cooperative state–minority relations and political stability in Satun province, and draws important lessons directly applicable to the unrest in neighbouring provinces.     

基于三粒子纠缠态的量子安全直接通信协议

提出了一种新的三粒子量子安全直接通信协议。通信过程利用decoy光子来检测窃听,保证信道安全。发送方将秘密消息编码在不同幺正操作上,通信双方通过Bell基和Z基测量可直接传递秘密消息。由于所有粒子都用于传输秘密消息,且传输一次可获得两比特信息,该协议具有较高的量子比特及量子密码协议效率;三粒子纠缠态的制备是已实现技术,该协议具有实际操作的意义。此外,该协议在量子信道中也是安全的。     

一种基于零控脱靶量的滑模末制导律设计

基于零控脱靶量的思想,提出一种能够有效针对大气层再入目标的滑模末制导律.首先,建立纵向平面内的弹目相对运动方程;然后利用扩张状态观测器对目标机动加速度信息进行估计,并对零控脱靶量算法进行分析,提出了制导律的设计思路;接着利用滑模变结构控制理论进行制导律的推导;最后进行仿真分析,仿真结果证明,所设计的制导律能够很好地对目标弹进行拦截,并且指令的跟踪效果也很好,从而验证了算法的有效性.     

基于变结构方法的空空导弹鲁棒逆控制律设计

为克服动态逆控制严重依赖被控对象精确数学模型且鲁棒性较差的缺点,将动态逆与变结构方法相结合采用双环结构设计了空空导弹鲁棒动态逆控制律.将导弹飞行状态划分成快慢2个回路,慢回路(外环)采用变结构控制,并设计扩张状态观测器,对外环中的不确定性进行估计;快回路(内环)采用动态逆控制.仿真结果表明,所设计的控制律具有较好的动态特性和鲁棒性能.     

基于GDOP的多基地雷达布站优化研究

以BLUE算法和GDOP为基本定位算法和精度分析工具,评估多基地雷达的定位性能,建立以GDOP最小值最小和有效监控区最大为目标的多基地雷达布站优化模型.仿真结果表明,通过以下措施可提高定位性能:①增加收发站总数;②采取扇形方式布站;③优先增加部署接收站;④交替部署收发站;⑤通过优化模型优化扇形布站分布角总和.