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.     

电工电子线路虚拟实验室的建设与应用

虚拟技术的发展使电子线路的分析设计过程得以在计算机上轻松、准确、快捷地完成。这样,一方面克服了实验室在元器件和规格上的限制,避免了损坏仪器等不利因素,另一方面使得实验不受时间及空间的限制,从而促进电子线路实验教学的现代化。     

弹载引信电控扫描识别目标方位的方法

研究了弹载引信电控扫描识别目标方位的一种方法，该方法是：首先研究一种周期电控脉冲起动单刀四掷微波开关，该开关又逐次起动可瞄准定向天线的每一元和它们的公共收发系统。因而该系统既能全向搜索空中目标，又能分区截取回波信号，由此获得引信天线电控扫瞄形式的可瞄准探测系统。     

无线电遥测监视小直径刀具的工况过程

小直径刀具(φ6mm以下小钻头、铣刀)加工中产生的磨、破损信号难于检测。本文基于这一问题,研究采用无线电遥测技术来传输传感器信号,并建立了CIMS,FMS加工中心钻、铣用小直径刀具的工况监视系统。研究表明:用遥测技术传输的切削过程信息是可以用来识别刀具切削状态的;小直径刀具折断快速报警的成功率在90％以上。     

虚拟样机技术在双模制导系统研制中的应用

将虚拟样机技术用于双模制导系统的研制。以Pro／E为三维实体特征建模工具，MSC、ADAMS为运动学和动力学分析工具，Matlab为控制分析软件，对机械系统和控制系统进行联合分析和调试。给出了机械模型、控制模型和两者间的输入输出，以及目标运动模型的建立方法。试验结果表明，所设计的虚拟样机能用于动态校核、参数优化、回归设计和演示验证，并能进行运动分析和干涉检测、跟踪以及交班试验等。     

基于虚拟仪器技术的测量船分布式状态监测

针对远洋航天测量船设备系统复杂、布局分散的特点，提出了利用虚拟仪器(VI)技术建立测量船网络化状态监测系统的方案。从硬件和软件两个方面阐述了虚拟仪器技术的性质和特点，以及分布式状态监测系统所采用的模式和工作方式。最后，介绍了测量船建立的总线虚拟仪器测试系统及其特点。     

现代微波测量的发展动态

从微波测量仪器、测量技术及测量分析出发 ,简单地阐述了现代微波测量发展的趋势。供微波测量人员参考     

基于PXI总线的瞄准电子设备虚拟计量检定系统

基于PXI总线和虚拟仪器的设计思想 ,提出了一种新型的瞄准电子设备虚拟计量检定系统的设计方案 ,对系统的硬件组成、检测原理和系统软件进行了论述 ,并对系统的校准问题进行了分析。     

Cyclotron masers and solar spike bursts

The theory of electron cyclotron maser emission and its application to solar spike bursts are reviewed. By analogy with the Earth's AKR, three sources of free energy are considered: a loss-cone anisotropy, a velocity-space hole, and a trapped distribution. The problem of how the radiation escapes through the second harmonic absorption layer is emphasized. Harmonic emission due to z mode coalescence may operate for some bursts, but the 2–5s delay between hard X-ray bursts and spike bursts suggests that some other mechanisms is required for most spike bursts. A model involving formation of a trapped distribution in low-density regions neighboring the flaring flux tube is considered.     

软件无线电侦察系统中的信号处理技术

软件无线电是无线通信领域特别是军事通信领域的一场革命,并已取得了长足的进展,软件无线电通信的侦察与对抗已成为一个十分紧迫的课题。本文对软件无线电侦察系统中的通信信号检测与分选技术进行了研究,为进一步研究提供了有用的参考。