双星定姿技术试验研究

本文深入探讨了双星定姿方法,仅利用2颗GPS卫星进行了实际的双星定姿试验.文中综合应用长短基线法和序列优化法求解整周模糊度.试验结果表明,当基线长约1m时,该方法定姿成功率达90%以上,定姿均方差优于0.5°      

卫星位置偏差对双星/GIS组合定位的影响及组合定位试验

建立了双星定位和双星／GIS组合定位的计算模型.在此基础上研究了星历误差对双星定位结果的 影响,卫星位置偏差对组合定位结果的影响,在组合定位中,在经、纬度方向上,分别给卫星位置加入均方差 为1°的位置偏差.结果表明,给卫星位置加入均方差为1°的经、纬度方向位置偏差,并不会降低组合定位的 精度.对这一重要结论,从几何上给出了解释.最后进行了双星／GIS组合定位的物理试验.试验结果表明, 双星／GIS组合定位确实可以大大提高双星定位的精度.     

双星定位系统/SINS深组合导航系统研究

以卫星模拟器为基础，介绍了一种双星定位系统定姿的基本原理，解决了双星定位系统存在的位置滞后即定位实时性较差的缺陷，把双星定位系统的位置与姿态信息和捷联惯导系统的位置、姿态信息进行组合后，可有效地提高系统的精度．     

极区中层惯性重力波的VHF雷达观测

本文采用ＳＯＵＳＹＶＨＦ雷达１９８７年６月在挪威Ａｎｄｏｐｖａ（６９°Ｎ，１０°Ｅ）的观测数据，研究中层惯性重力波的传播特征．几个周期为数小时的准单色波例子，在垂直方向上有确定的相位移动，表明它们是惯性内重力波．通过分析波相关的流体速度东向和北向分量的变化，获得水平传播矢量的大小和方向，它们与中层高度上典型的观测值一致．同时还观察到三个等相面上行的惯性重力波，其速度偏振椭圆是逆时针旋转的．波相关的扰动速度为１５－４０ｍ／ｓ，说明在中层存在强烈的向下的能量传输．估算出它的运动学参量，周期为数小时，垂直相速度在０．ｌ—０．６ｍ／ｓ之间，垂直波长约为６．０ｋｍ．     

中国向国际电联登记的静止卫星轨道位置表

登记的卫星名称１）国内用的名称轨道位置频段登记情况２）ＳＴＷ－１试验通信卫星１２５°ＥＣＮＳＴＷ－２试验通信卫星１０３°ＥＣＮＣｈｉｎａｓａｔ－１东方红－２甲８７．５°ＥＣＮＣｈｉｎａｓａｔ－２东方红－２甲１１０．５°ＥＣＮＣｈｉｎａｓａｔ－３东方红－２甲９８°ＥＣＮＣｈｉｎａｓａｔ－４东方红－２甲１３０°ＥＣＡＣｈｉｎａｓａｔ－１１银行星１０１．５°ＥＫｕＡＣｈｉｎａｓａｔ－１２银行星１０５°ＥＫｕＡＣｈｉｎａｓａｔ－２１烽火－１１０３°ＥＵＨＦ，Ｃ＊Ｃｈｉｎａｓａｔ－２２烽火－１９８°ＥＵＨ…     

地球同步卫星业务一览表

地区卫星名称经营者发射年份转发器／台频段寿命／年轨道位置北美　兄弟卫星－Ｅ１、Ｅ２１）　加拿大电信卫星公司１９９１、１９９１２４１６ＣＫｕ未知１１１．１°Ｗ、１０７．３°Ｗ　极光卫星－２（Ｃ５）　美国电话电报与ＧＥ公司１９９１２４Ｃ１２１３９°Ｗ　加...     

双星/GIS组合定位建模与仿真

双星定位系统具有快速高精度定位和简短报文通信的功能．为了进一步提高定位精度，满足特殊用户需要，文中提出了由双星和道路地理信息系统组合定位的新方法，并做了计算机仿真试验，进行了组合定位精度分析．分析结果表明，该方法可明显提高双星定位精度，在适当条件下组合定位均方差小于10m。     

CCD星敏感器光学系统设计

介绍ＣＣＤ星敏感器用光学系统设计的参数选择,光学系统的设计光谱范围０．４８、０．８５μｍ;焦距为７５ｍｍ,Ｆ／１．４４,视场８．５°。该系统为复杂化的Ｐｅｔｚｖａｌ结构形式;以点列图能量集中度和能量重心偏评价光学系统的成像质量。所选用的ＣＣＤ芯片像元尺寸为２３μｍ×２３μｍ,像元数３８４×２８８,全视场内混色光点列图能量重心偏最大值１．６μｍ,对应于４．３９角秒。     

新闻摘要

中国将在1990年9月发射第2颗风云号气象卫星。第一颗风云一号卫星实际只工作了39天,因姿控系统及一台辐射计故障而停止工作。风云一号卫星上有两台辐射计,地面分辨率为1100米,太阳翼跨度为8.6米。这是法刊7月15日《航空与宇宙》报导的。国际通信卫星组织申请Intelsat-7卫星的8个位置,它们是东经57°、60°、66°、310°、319.5°、329°、335.5°和338.5°。沙特阿拉伯建成斯波特卫星接收站,该站位于利雅得,这是中东第一座斯波特卫星     

各国发射成功的宇宙飞行器统计表(1995年1～6月)

名称国别发射日期近地点／ｋｍ远地点／ｋｍ周期／ｍｉｎ倾角／（°）备　注国际通信卫星－７０４国际通信卫星组织１９９５－０１－１０３５７９４３５８１０１４３６．８７０．０１商业通信卫星，定位在６６°Ｅ蝉－１俄罗斯１９９５－０１－２４９６５１０２１１０４．...     

Learning in an immersive digital theater

The Houston Museum of Natural Science, in collaboration with Rice University has an outreach program taking portable digital theaters to schools and community sites for over five years and has conducted research on student learning in this immersive environment. By using an external independent evaluator, the effectiveness of NASA-funded Education and Public Outreach (EPO) projects can be assessed. This paper documents interactive techniques and learning strategies in full-dome digital theaters. The presentation is divided into Evaluation Strategies and Results and Interactivity Strategies and Results. All learners from grades 3–12 showed statistically significant short-term increase in knowledge of basic Earth science concepts after a single 22-min show. Improvements were more significant on items that were taught using more than one modality of instruction: hearing, seeing, discussion, and immersion. Thus immersive theater can be an effective as well as engaging teaching method for Earth and Space science concepts, particularly those that are intrinsically three-dimensional and thus most effectively taught in an immersive environment. The portable system allows taking the educational experience to rural and tribal sites where the underserved students could not afford the time or expense to travel to museums.     

Scaling analysis and model estimation of solar corona index

A monthly average solar green coronal index time series for the period from January 1939 to December 2008 collected from NOAA (The National Oceanic and Atmospheric Administration) has been analysed in this paper in perspective of scaling analysis and modelling. Smoothed and de-noising have been done using suitable mother wavelet as a pre-requisite. The Finite Variance Scaling Method (FVSM), Higuchi method, rescaled range (R/S) and a generalized method have been applied to calculate the scaling exponents and fractal dimensions of the time series. Autocorrelation function (ACF) is used to find autoregressive (AR) process and Partial autocorrelation function (PACF) has been used to get the order of AR model. Finally a best fit model has been proposed using Yule-Walker Method with supporting results of goodness of fit and wavelet spectrum. The results reveal an anti-persistent, Short Range Dependent (SRD), self-similar property with signatures of non-causality, non-stationarity and nonlinearity in the data series. The model shows the best fit to the data under observation.     

Stochastic particle acceleration by the forced interaction of relativistic current sheets

We address the problem of interacting relativistic current sheets in self-consistent kinetic plasma simulations within the framework of the Particle-In-Cell model. The interaction is enforced in head-on collisions of up to 10 current sheets at relativistic bulk speeds. The simulations are motivated by the general problem of Poynting flux dissipation in ‘striped wind’ configurations presumably governing the relativistic outflows pervasive in pulsar winds and gamma-ray bursts. We identify the generation of non-thermal particles and formation of a stable power-law shape in the particle energy distributions f(γ) dγ ∝ γ^−s dγ. In 1D, a spectral index s ∼ 2 is observed and attributed to a stochastic Fermi-type acceleration mechanism. In 2D, the generic index of s ∼ 3–4 is retained as in previous simulations of individual current sheets. Whereas in 2D the high energy cut-off is constrained by the limited dissipation of magnetic energy, in 1D the process converts the bulk motion of current sheets towards directed particle momentum of an exclusive class of non-thermal particles.     

Development of a gas chromatography compatible Sample Processing System (SPS) for the in-situ analysis of refractory organic matter in martian soil: preliminary results

In the frame of the 2009 Mars Science Laboratory (MSL) mission a new sample preparation system (SPS) compatible with gas chromatography–mass spectrometry (GC–MS) has been developed for the in situ analysis of complex organic molecules in the Martian soil. The goal is to detect, if they exist, some of the key compounds that play an important role in life on Earth including carboxylic acids, amino acids and nucleobases.     

基于LuGre模型的电液加载系统摩擦补偿

为了提高电液加载系统控制精度,针对摩擦问题提出了基于LuGre摩擦模型的前馈补偿方法.建立了用于摩擦仿真分析和补偿器设计的电液加载系统数学模型;通过实验获取并分析了相关的摩擦数据;基于实验数据进行LuGre模型参数辨识,把LuGre模型和辨识结果引入电液加载系统数学模型,并进行仿真结果与实际摩擦数据的对照,证明了LuGre摩擦模型的准确性.设计前馈补偿器,进行了实验对比,实验结果表明前馈补偿器可将摩擦产生的控制误差有效地降至未补偿时的30%左右.      

CoRoT and Kepler results: Solar-like oscillators

The space-borne observatories CoRoT (Convection Rotation and planetary Transits) and Kepler have provided photometric time series data of unprecedented precision for large numbers of stars. These data have revolutionized the fields of transiting exoplanets and asteroseismology. In this review some important asteroseismic results obtained using data from the CoRoT and Kepler space missions concerning stars that show solar-like oscillations are discussed. These results comprise, among others, measurements of the location of the base of the convection zone and helium second-ionization zone in main-sequence stars, the presence (or not) of core-helium burning in red-giant stars, as well as differential rotation in these stars.     

Return to Europa: Overview of the Jupiter Europa orbiter mission

Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, the Galileo spacecraft supplied fascinating new insights into this satellite of Jupiter. Now, an international team is proposing a return to the Jupiter system and Europa with the Europa Jupiter System Mission (EJSM). Currently, NASA and ESA are designing two orbiters that would explore the Jovian system and then each would settle into orbit around one of Jupiter’s icy satellites, Europa and Ganymede. In addition, the Japanese Aerospace eXploration Agency (JAXA) is considering a Jupiter magnetospheric orbiter and the Russian Space Agency is investigating a Europa lander.     

Radioactivity of the Moon and planets

In this report the main results of the study of radioactivity of the solar sistem bodies are considered. The radioactivity of the Moon and planets was measured by means of vehicles in situ. The radioactivity of the lunar samples, brought to the Earth was studied with laboratory equipment.     

基于最小值原理的冗余度机器人动力学控制

为了解冗余度机器人全局法优化中数值求解的困难,本文讨论了动力学方程的建立,无约束和有约束最优控制问题之间的内在联系,重点分析了求解最优控制问题的数值方法,文中提出了双向异步积分迭代的求解正则方程组的直接迭代法,较好解决了状态方程和协态方程稳定相逆给求解两点这值问题带来的困难。     

基于GPS载波相位的微卫星姿态算法研究

GPS姿态系统是利用GPS载波相位测量来确定载体的航向和姿态角。本文对微卫星的GPS姿态系统进行了研究。重点解决短基线的GPS状态算法，讨论了姿态价格函数的了小化方法。测试结果表明，所提的算法对小于1m的基线是有效的。