A comprehensive survey on the methods of angle of attack measurement and estimation in UAVs

Angle of Attack (AOA) is a crucial parameter which directly affects the aerodynamic forces of an aircraft. The measurement of AOA is required to ensure a safe flight within its designed flight envelop. This paper intends to summarise a comprehensive survey on the measurement techniques and estimation methods for AOA, specifically in Unmanned Aerial Vehicle (UAV) applications. In the case of UAVs, weight constraint plays a major role as far as sensor suites are concerned. This results in selecting a suitable estimation method to extract AOA using the available data from the autopilot. The most feasible and widely employed AOA measurement technique is by using the Multi-Hole Probes (MHPs). The MHP measures the AOA regarding the pressure variations between the ports. Due to the importance of MHP in AOA measurement, the calibration methods for the MHP are also included in this paper. This paper discusses the AOA measurement using virtual AOA sensors, their importance and the operation.     

Topology optimization in lightweight design of a 3D-printed flapping-wing micro aerial vehicle

Topology optimization is an effective method to obtain a lightweight structure that meets the requirements of structural strength. Whether the optimization results meet the actual needs mainly depends on the accuracy of the material properties and the boundary conditions, especially for a tiny Flapping-wing Micro Aerial Vehicle (FMAV) transmission system manufactured by 3D printing. In this paper, experimental and numerical computation efforts were undertaken to gain a reliable topology optimization method for the bottom of the transmission system. First, the constitutive behavior of the ultraviolet (UV) curable resin used in fabrication was evaluated. Second, a numerical computation model describing further verified via experiments. Topology optimization modeling considering nonlinear factors, e.g. contact, friction and collision, was presented, and the optimization results were verified by both dynamic simulation and experiments. Finally, detailed discussions on different load cases and constraints were presented to clarify their effect on the optimization. Our methods and results presented in this paper may shed light on the lightweight design of a FMAV.     

自适应控制方法的直接命中目标本体的平行接近制导律

本文在最少量测条件下采用视线角速度ｑ趋于零的指标函数和低阶等效辨识模型与快速自适应控制方法实现了战术导弹的平行接近制导律。这种最优制导律可以实现直接命中目标本体，实现一弹多用，可以用于反导弹的控制。能使制导装置简化并使其尺寸和重量减小，算法简单易于工程使用。经过大量数学和半实物仿真试验表明，上述成果可应用于实际工程当中。     

ILD智能交通流量测试仪

介绍一种交通流量测试仪，它具有高灵敏度、高信噪比、传输距离远，可以准确地测量机动车、自行车流量，且成本低。由于该仪器设置了驱动变送器，采用了一种新的传输结构，引入了微机技术，模式识别等技术，从而研制出性能稳定、操作方便、实用性强且具有国际先进水平的道路交通流量测试装置。     

最少燃料消耗的固定推力共面轨道变轨研究

本文研究了推力固定条件下，从圆轨道进入共面圆轨道一次入轨最节省燃料的推力方向控制策略。这类问题都可归结为两点边值问题，对自由初值的选取作了讨论，并采用打靶法迭代求解。计算了从停泊轨道到同步转移道以及两个过地圆轨道之间的最优转移，获得满意的结果。     

FY—1C卫星高分辨率云图传输技术

介绍了FY－1C星传输系统的任务、方案、主要技术指标和组成。系统采用极化隔离加带外频谱抑制的方法，达到了信道隔离的技术指标。概述了星载记录器由磁带记录器向固态记录器转变的技术因素以及磁带记录器、FLASH和DRAM固态记录器的研制过程。简述了传输系统在轨测试和运行状况。     

激光靶斑阵列数据遥测系统传输特性分析

介绍了一种用于激光靶场试验中测量激光靶斑阵列数据的ＷＹＫ２１遥测系统，对该系统的传输特性，包括数据传输误码率，遥测接收灵敏度和系统功率传输裕量进行了分析研究。     

用计算机求最小外接圆和最大内切圆的快速,精确方法

文中分别介绍了用计算机求最小外接圆和最大内切圆的新算法。该算法中每一步都能确定圆心的最佳移动方向,沿该方向的圆心移动量可由公式确定,从而只需少数几步迭代就可求得实际轮廓的最小外接圆和最大内切圆的精确位置。     

附加准直器的带顶盖静电分析器的数值模拟

对准直器限定视场的带顶盖的1／4球分析器的物理特性分析了数值模拟，相应的模拟程序是在修改裸分析器模拟程序后发展起来的。新程序了准直器引起的分析器结构配置的变化，且被应用于一个带准直器的分析器样本，产生了传输函数和几何因子的模拟结果。     

无人机高速DS/FH混合扩频通信系统关键模块设计

针对UAV(Unmanned Aerial Vehicle,无人机)测控链路高抗干扰需求,给出了实现跳频速率20 000次/s的扩跳混合无人机测控数据链系统实现方案.系统采用跳频频率并行捕获模式.跳频源设计采用直接频率合成、DDS(Direct Digital Synthesis,直接数字频率合成)和PLL (Phase-Locked Loop,锁相环)相结合的混合频率合成技术.利用相位响应滤波器,通过正交调制技术完成MSK(Minimum Shift Keying,最小频移键控)、GMSK (GaussianMinimum Shift Keying,高斯最小频移键控)调制.通过推导得出2 bit差分解调输出与载波频率选择有关,且为四分之数据率的整数倍关系.然后通过实例分析给出了跳频频率间隔选取方法,即跳频间隔应当将临近跳频的主瓣分开,同时跳频载波频率应当设在其他跳频频谱的零点处.最后总结了高速扩跳频系统参数设计一般步骤.