交会对接任务天基双目标测控通信设计

针对交会对接任务对测控通信提出的高覆盖率和双目标测控等需求的问题,分析2颗中继卫星能够提供的覆盖率,设计双目标测控工作模式以及天地协同机制,计算中继链路的性能,分析表明,天基测控可提供约72%的测控覆盖率,能够支持双目标测控,链路余量满足要求;统计了任务中关键段落的测控通信工作情况,分析结果和实际任务情况验证了天基测控在交会对接任务测控通信中的重要作用;最后提出后续任务改进和完善的建议。     

一种基于多无人机的中继节点布置问题建模与优化方法

针对战场环境下急需在无法通信的节点间构建有效通信链路的情形,使用多无人机作为中继节点,建立了中继节点布置(RNP)问题模型。模型以中继链路有效和无人机安全为约束,以中继布置点位置及相应的无人机为输出,不但考虑了使用的中继无人机数量,还考虑了构建中继链路花费的时间。考虑到该问题是难以求解的混合整数多目标优化问题,同时在紧急应用情形下,要求求解算法快速有效,建立了一种多项式时间中继节点布置算法(PTRPA)。仿真实验验证了所提模型确实能够在更短的时间内完成有效中继链路构建;通过Monte-Carlo方法对比和分析不同因素对PTRPA算法、随机抽样算法、遗传算法求解该问题的结果性能和时间性能的影响,验证了PTRPA算法不但能够给出接近最优的解,且快速有效,满足战场决策需求。     

我国中继卫星系统在交会对接任务中的应用

我国中继卫星系统在交会对接任务中得到了成功应用,显著提升了测控通信覆盖率,充分体现了中继卫星系统在交会对接任务测控通信中发挥的重要作用.结合中继卫星系统特点,分析交会对接任务对中继卫星系统的任务需求;探讨了中继卫星捕获跟踪用户目标、对用户目标测定轨、着陆场直升机缝隙通信等关键技术;最后总结了中继卫星系统抗雨衰影响、多目标支持能力、应急支持能力等方面的经验做法,并提出了后续改进和完善的建议.     

深空中继通信束聚合效能研究

针对深空中继通信环境中BP/LTP协议加入束聚合策略对数据传输效率的影响问题,建模分析LTP数据块传输时间,考虑多会话并发及中继节点参与,获得应用数据在深空中继环境中总传输时间的期望,分析出束聚合策略对深空中继通信性能的影响。通过数值实验对不同束聚合值在典型深空中继通信环境中的效率进行了检验。结果表明:在应答链路不阻塞的约束下,越小的束聚合规模传输效率越高,且节点发送缓存大小对性能有重要影响。     

中继卫星天线指向控制策略研究

首先根据中继卫星系统中中继卫星跟踪用户星的要求,定义了中继卫星天线坐标系,推导出了中继卫星天线对用户星的跟踪规律,通过该跟踪规律可以推出中继卫星跟踪用户星时天线方位和俯仰轴转角,为了保证中继卫星与用户星之间的通信,中继卫星单址天线需要精确的指向用户星;然后详细描述了天线指向控制概念,并且设计了星上自主控制方案,星上自主控制方案由捕获和自动跟踪模式组成,一方面设计了天线捕获过程,另一方面对自动跟踪模式的天线步进逻辑进行了合理选择;最后根据推导的跟踪规律,以不同轨道的用户星作为跟踪目标,对所设计的天线指向控制系统进行了数学仿真,并且通过对仿真结果的分析验证了中继卫星单址天线指向性能。     

基于喷泉编码的中继信道协作方案

首先给出了二进制删除中继信道下基于喷泉编码的多种协作方案,并依性能得出了最优方案,此后借鉴渐近最优喷泉编码的概念,将该最优协作方案扩展到无线中继信道中,并利用排队理论实现了中继节点的最优流量控制,给出了无线中继信道下的中继流控制协作方案。仿真结果表明,基于喷泉编码的中继信道协作方案有效地解决了中继缓存溢出问题,提高了信道的可达速率。     

宽波束中继技术在空间站任务中的应用研究

针对航天器现有窄波束中继终端天线在姿态快速变化及姿态异常条件下提供测控支持的局限性,提出了利用宽波束中继技术提供测控通信支持的方案。基于宽波束中继天线性能、天地链路性能对测控通信支持的影响分析,提出了改善链路性能的优化方案。结合空间站任务载人航天器各阶段测控通信支持的特点,分析了宽波束中继在入轨段、长期运行段和返回段的应用。分析结果表明:宽波束中继可为载人航天器从海南发射场发射时的入轨提供测控支持,也可为载人飞船返回提供测控支持。     

非对称衰落信道下无人机中继传输方案及性能分析

 无人机(UAV)作为中继传输平台受到了国内外研究人员的广泛关注。本文研究了非对称衰落信道下的无人机中继传输系统,提出了输出信噪比最大化准则下的波束形成(BF)优化方案,并推导出系统中断概率、遍历容量和平均误符号率等无线通信系统主要性能指标的理论表达式。通过计算机仿真验证了本文提出的中继传输方案及性能分析的正确性,并定量分析了天线数量、信道参数以及功率分配对系统性能的影响,为无人机中继传输系统的设计及性能评估提供了参考和依据。     

中继卫星系统链路操作影响因素分析

中继卫星系统链路建立和维持是中继卫星系统的关键技术，其直接影响中继卫星系统为用户提供数据中继服务的质量。影响链路建立和维持等操作的因素较多，有些还存在一定的关联性。本文分析给出了影响中继卫星系统捕获跟踪用户平台性能的几个主要因素，如链路建立时间、链路建立概率、中继卫星对用户平台的程序跟踪误差、中继卫星对用户平台的自动跟踪误差等，并就各种因素对中继卫星系统链路操作的影响进行初步评估。     

直升机加装数据中继设备的设计与分析

直升机因具有低速、机动灵活、起降要求低等特点而得到广泛使用,而空中数据中继转发设备的加改装将进一步拓展直升机任务面。基于某型直升机加装空中数据中继转发站的实际工作,对加改装设计过程进行分析,计算了各部件安装后的受力强度,给出了加装设备结构强度和质心的计算方法,并对加装设备与直升机的电磁兼容性能和设备本身的通信性能进行了分析。结果表明,空中数据中继转发站加装后符合法规要求的结构强度和电磁兼容性等适航要求,且通信性能满足超视距数据中继任务要求。因此,该项工作可为同类型改装工作提供参考和借鉴。     

“Reinventing” career development

The following topics are dealt: career development definition; career development as a part of effective management; job satisfaction issues; motivated abilities; a case study results; identification of motivational patterns; and 'reinvention' of career development     

Magnetospheric Science Objectives of the <Emphasis Type="Italic">Juno</Emphasis> Mission

In July 2016, NASA’s Juno mission becomes the first spacecraft to enter polar orbit of Jupiter and venture deep into unexplored polar territories of the magnetosphere. Focusing on these polar regions, we review current understanding of the structure and dynamics of the magnetosphere and summarize the outstanding issues. The Juno mission profile involves (a) a several-week approach from the dawn side of Jupiter’s magnetosphere, with an orbit-insertion maneuver on July 6, 2016; (b) a 107-day capture orbit, also on the dawn flank; and (c) a series of thirty 11-day science orbits with the spacecraft flying over Jupiter’s poles and ducking under the radiation belts. We show how Juno’s view of the magnetosphere evolves over the year of science orbits. The Juno spacecraft carries a range of instruments that take particles and fields measurements, remote sensing observations of auroral emissions at UV, visible, IR and radio wavelengths, and detect microwave emission from Jupiter’s radiation belts. We summarize how these Juno measurements address issues of auroral processes, microphysical plasma physics, ionosphere-magnetosphere and satellite-magnetosphere coupling, sources and sinks of plasma, the radiation belts, and the dynamics of the outer magnetosphere. To reach Jupiter, the Juno spacecraft passed close to the Earth on October 9, 2013, gaining the necessary energy to get to Jupiter. The Earth flyby provided an opportunity to test Juno’s instrumentation as well as take scientific data in the terrestrial magnetosphere, in conjunction with ground-based and Earth-orbiting assets.     

具有纳米结构的 VO₂ 相变薄膜

 采用无机溶胶-凝胶法制备VO₂相变薄膜，该薄膜相变时的电阻（率）突变可达4～5个数量级。并用XRD,DSC和TGA法研究了制膜过程中干凝胶膜的层状非晶纳米结构。通过适当的非晶晶化过程及随后V₂O₅→VO₂转变的真空热处理，可获得带有空洞（void）结构的低密度纳米薄膜，从而使电阻（率）突变特性异常优异。     

Fuel cells for “personal electricity”

Cars powered by fuel cells have been built and tested; however, the aerospace fuel cells could not deliver high power quickly when the driver wanted to accelerate his car. Today's hybrid electric cars carry a battery that supplies the acceleration power, and the prime power source, whether an engine or fuel cell, is not stressed with sudden load peaks. Zero air pollution becomes attainable when fuel-cells supply the prime power on a hybrid vehicle     

H_∞中的规范化LCF法在综合控制系统设计中的应用

 用鲁棒控制理论中的规范化左互质因子分解(规范化LCF)法为某型飞机设计纵向飞/推综合控制器,并总结了该方法的一些特点和设计要求。设计出的控制器满足实际工程要求,得到比较满意的控制效果。     

Simulation of <Emphasis Type="Italic">Z</Emphasis>-crimp shaping with the use of the ansys finite element software

A finite element model of the Z-crimp shaping from a hard sheet blank is developed and a number of calculations using the ANSYS finite element software is conducted. The calculations are carried out in the framework of elastoplastic behavior of the blank material using the classical model of bilinear kinematic (translational) hardening with corresponding parameters of elasticity and plasticity. The model takes into account kinematics of spatial transformation of the shaping equipment as well as the time-variable conditions of its contact interaction with the blank.     

Sedimentation stability of fullerene C<Subscript>60</Subscript> particles in sulphamate nickel-plating electrolyte

The techniques of injecting nanomodifiers into the sulphamate electrolyte used for electrolytic forming of nickel antiabrasive protective tipping are considered. The optimal concentration of surfactant and nanomodifier are determined. The graphs are also presented.     

工业再设计破局“中国制造2025”

安世亚太和苏氏集团正式结为战略联盟,利用各自的优势打造集成"精益研发技术+精密铸造工艺"的工业再设计体系。战略联盟的建立将安世亚太精益研发、工程仿真技术与苏氏精密铸造工艺相结合,启动工程仿真驱动的工业再设计过程,让设计突破工艺局限,敢于跨量级优化,并产生颠覆式创新。     

“Dakota Sun”-the next generation solar powered racingvehicle

Based on the experience gained from Sunrayce '95, the Solar Motion Team has made many changes to the design of the next generation solar car. These changes have resulted in a vehicle that is very different from the “Solar Rolar”, The Dakota Sun is a three wheeled vehicle with separate cab and solar array. This design allows for improved aerodynamics, decreased weight, lower rolling resistance, and ease of manufacture compared to the four wheeled catamaran used in the last race. However, this design sacrifices total enclosed wheel base area, additional room for components, and added power from side solar panels, The major objectives for the team's redesigned Sunrayce '97 entry are: systems integration; decrease the weight of the car; decrease aerodynamic drag; more efficient use of available energy; and increased driver safety. The team has set a standard to use the latest available technology. Although this increases the complexity of the components, by using a systems engineering approach the “Dakota Sun” has evolved into a more integrated vehicle. This philosophy of integrated design has resulted in great improvements in mechanical design and manufacturing techniques, as well as electrical innovations. The major design changes evident from the original Sunraycen '95 vehicle are the result of an evolutionary design process that has produced the highly competitive Sunraycel '97 design outlined in this article