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.     

平面形状误差分离方法的比较分析

就十种典型的精密平面形状误差测量－分离方法的权函数及其零点，作了分析比较。按形状误差谐波抑制最小准则，论证了五点式正交逐次三点法、九点式正交逐次三点法、复合三点法、不对称二维混合法和不对称四点法优于其他方法，不对称四点法则较为理想。     

原子时自动测量及数据采集系统

介绍了普通的时间实验室的时频测量,实现自动测量和数据收集的基本系统方案,并以上海天文台原子时实验室为例介绍了实际可行的自动测量和数据收集系统,这个系统高性能、低价格,可应用于国内几乎所有的时间实验室。     

高频大电压标准器

主要阐述了该标准器的基本原理,从理论上对结构补偿法进行了分析和数学推导,当R/Z_o=1.9～2.0之间时,具有最小的交直流差。设计了匹配的同轴热电转换标准器;进行了误差分析;给出了试验结果,说明该标准器交直流差的重复性和复现性是好的。     

Measuring the matter distribution within z = 0.2 cluster lenses with XMM-Newton

We present an analysis of seven clusters observed by XMM-Newton as part of our survey of 17 most X-ray luminous clusters of galaxies at z  0.2 selected for a comprehensive and unbiased study of the mass distribution in massive clusters. Using the public software FTOOLS and XMMSAS we have set up an automated pipeline to reduce the EPIC MOS and pn spectro-imaging data, optimized for extended sources analysis. We also developped a code to perform intensive spectral and imaging analysis particularly focussing on proper background estimate and removal. XMM-Newton deep spectro-imaging of these clusters allowed us to fit a standard β-model to their gas emission profiles as well as a standard MEKAL emission model to their extracted spectra, and test their inferred characteristics against already calibrated relations.     

基于信息熵的飞机相似机型确定方法

参考类似机型的经验是我国目前民用飞机研制的主要途径之一。为了更好地借鉴国内外类似机型的经验,本文提出了一种基于信息熵的类似机型确定方法,该方法应用信息熵理论,直接通过类似机型数据所蕴含的客观信息计算各属性的权重,消除了依靠人为指定权重的主观因素影响。在此基础上,给出了包含有不精确信息属性的相似度的计算方法,最后应用支线飞机实例进行了验证,表明该方法具有较高的客观有效性。     

高精度圆度仪误差分离装置研制及测量不确定度分析

介绍了一种由程控型多齿分度台和高精度圆度仪组合而成的全自动误差分离装置，该装置能够使圆度仪主轴回转误差从被测工件测量结果中可靠分离，从而极大地提高了圆度测量不确定度，本文对该装置测量不确定度进行了分析。     

激光外差干涉仪光电信号处理方法及特点

叙述和分析了外差激光干涉光电信号处理主其特点，指出了它们各自的应用范围，同时介绍了一处新型的光电信号处理方法，它不仅使外差干涉仪用于动态测量，而且可以同时实现高分辩率测量 。     

一种新的六端口测量系统自校准方法

提出了一种新的六端口自校准方法.本方法从六端口相对功率理论出发,导出了六端口系统常数的自校准方程,给出了求解系统常数初值的方法,并利用梯度法对方程组求解,仿真结果表明用一个匹配负载、四个失配负载就可以解出系统常数.     

超声波法测量燃速初探

针对国内首次引进的超声波实时燃速测量系统编写了测试软件,用水作为被测试对象,进行了退移速率测量,分析了超声波测量燃速的主要影响因素。结果表明,测量精度主要受材料中声速的约束,声速会受到材料应力(压强)和温度的影响。该软件可以用于厚度、材料内声速和实时燃速测量。