多视场星敏感器工作模式设计

针对多视场星敏感器的特点设计了两种工作模式:高精度工作模式和高更新率工作模式.中央时序控制器根据指令完成工作模式配置,以相应的时序启动图像采集处理模块.结合工作模式的时序特点,在FPGA(Field Programmable Gate Array)内部设计了3个星点质心提取模块,与各自对应的图像采集模块同步运行,实现了两种工作模式下多视场星图快速质心提取.采用Cypress公司的IBIS5-A-1300作为图像传感器,基于FPGA设计了实验平台,对工作模式配置及数据更新率进行测试.实验结果表明:工作模式可灵活配置和切换,在高更新率工作模式下,星敏感器的数据更新率为传统单视场情况的3倍.     

HORACE: A compact cold atom clock for Galileo

HORACE (HOrloge à Refroidissement d’Atomes en Cellule = clock based on atoms cooled from vapour cell) is a compact cold caesium atom clock developed in SYRTE at Paris Observatory. This clock can operate both on ground and in microgravity environment. Design of HORACE is based on isotropic light cooling, allowing performing the whole clock sequence (cooling, atomic preparation, Ramsey interrogation and detection) at the same place. Compared to more conventional cold atom clocks such as atomic fountains, the use of isotropic light cooling simplifies both the optical part of the setup and the detection sequence, and leads to a drastic size reduction of the physics package. Very good short-term performances have been demonstrated at SYRTE since relative frequency instability of 2.2 × 10⁻¹³ τ^−1/2 has been obtained. Optimization of the long term stability is still under progress and current results show relative frequency instability around 3 × 10⁻¹⁵ in 10⁴ s of integration. With these performances, HORACE appears as a good candidate both for Galileo’s ground segment clock and for onboard Galileo clock.     

基于CCD的单缝衍射条纹光强测量与小波去噪技术研究

通过CCD的数据采集对单缝衍射条纹的光强进行测量试验,简要分析了试验中的噪声来源.提出使用小波技术对CCD的采集信号进行噪声滤除,详细讨论了小波的分解与重构以及在去除噪声中的应用.试验结果表明,小波技术能完全滤除噪声.     

杭州市高星级酒店节能降耗调查研究

伴随绿色环保、节能降耗的经济发展背景,酒店业采取了相应的节能降耗措施。通过对杭州市高星级酒店进行问卷调查和访谈调研,了解高星级酒店的能源消耗和资源浪费程度,以及酒店节能降耗措施的实施情况,提出可操作性强且值得推广的一些改进建议。     

轻型航空发动机二级涡轮增压匹配模拟研究

为了使现有轻型航空发动机在10km高空保持原有动力性不变,需要采用二级涡轮增压保持不同海拔高度的进气密度。对原发动机在一级增压的基础上进行二级增压匹配。这里采用AVL Boost软件建模,根据实验校验一级增压模型,然后建立二级增压模型。考虑小型离心式压气机高海拔工作特性受雷诺数影响,确定了压气机匹配工作点。计算表明,匹配方案可行,原发动机满足飞行设计要求。     

偏振光导航

本文简单的介绍了偏振光导航的发展背景、偏振光导航的基本原理以及偏振光导航的发展历程,同时提出了偏振光导航需要解决的问题。     

Process of establishing design requirements and selecting alternative configurations for conceptual design of a VLA

In this study, a process for establishing design requirements and selecting alternative con-figurations for the conceptual phase of aircraft design has been proposed. The proposed process uses system-engineering-based requirement-analysis techniques such as objective tree, analytic hier-archy process, and quality function deployment to establish logical and quantitative standards. Moreover, in order to perform a logical selection of alternative aircraft configurations, it uses advanced decision-making methods such as morphological matrix and technique for order prefer-ence by similarity to the ideal solution. In addition, a preliminary sizing tool has been developed to check the feasibility of the established performance requirements and to evaluate the flight perfor-mance of the selected configurations. The present process has been applied for a two-seater very light aircraft (VLA), resulting in a set of tentative design requirements and two families of VLA configurations: a high-wing configuration and a low-wing configuration. The resulting set of design requirements consists of three categories: customer requirements, certification requirements, and performance requirements. The performance requirements include two mission requirements for the flight range and the endurance by reflecting the customer requirements. The flight performances of the two configuration families were evaluated using the sizing tool developed and the low-wing configuration with conventional tails was selected as the best baseline configuration for the VLA.     

飞机驾驶舱自动调光系统中光照传感器布局设计

为满足飞机驾驶舱自动调光系统中环境光检测需要,本文提出一种光照传感器布局方法,该布局方法首先利用SPEOS光学仿真软件分析驾驶舱各区域在不同季节、航向、时间点时的环境光分布;其次,结合各区域发光器件分布情况,确定出光照传感器安装的候选位置;最后,在自然光环境下验证光照传感器候选位置的合理性,并根据验证结果确立光照传感器安装位置。该布局设计方法结合了光分布仿真分析的快速性、可重复性和自然光环境验测真实性的优点,能实现驾驶舱光照传感器的合理布置,为驾驶舱自动调光系统提供准确的环境光信息。     

基于Hausdorff距离的星图识别方法

提出了一种新的星图识别方法,这种方法的基本思想是首先从星敏感器中提取全部星图信息,把提取的星图组成一个待识别数据集合B,把全星图参考星库作为一个标准数据集合A,然后,计算2个数据集合A,B之间的相对Hausdorff距离,根据最小相对距离得到待识别星的位置,其中A, B分别由矢量坐标a,b构成.与传统的星光角距识别方法不同,这种方法充分利用了星敏感器中的所有星的空间结构信息,所以,它对各种噪声干扰具有很强的鲁棒性.半物理仿真实验结果表明,在具有强的随机噪声、星图畸变和一定数目的流星干扰情况下,这种方法具有很好的识别效果.     

轻型飞机翼梢减阻外形的风洞实验研究

介绍了三种翼梢减阻装置：后掠翼梢、分段后掠机翼和下弯翼梢。重点给出改变后掠翼梢的几何参数对减阻效果的影响。风洞实验表明,经优化设计的后掠翼梢可使诱导效率ｅ提高４％～７％。后掠翼梢使飞机纵向静稳定性增大。水洞实验表明,后掠翼梢减阻的原因主要是在有迎角时,翼梢前缘涡和后缘涡共问作用削弱了翼梢涡,从而减小了飞机的诱导阻力。