国际电联关于地球静止轨道资源的决议

国际电联关于地球静止轨道资源的决议国际电信联盟（ＩＴＵ，简称国际电联）最近发表了题为《国际电联在空间通信方面的目前活动》的报告。现将其中与地球静止轨道、频谱资源分配有关的第一节（引言）、第六节（对决议１８的审查）和第七节（收取成本费）摘译如下，供参阅...     

国际电联对卫星系统登记将收取程序费的有关决议

１　背景介绍１９９４年在日本京都举行的国际电联（ＩＴＵ）全权代表大会上制定了１５和３９号决议。决议主要涉及电联各机构成员的权利与义务及加强电联财政基础的问题。在１９９６年的会议期间，电联委员会根据其４７１号决定，成立了ＩＴＵ－２０００工作组，此小组旨在执行针对１５和３９号决议的深入研究。在本届大会的第三次会议期间（１９９７年４月２１日～２５日），ＩＴＵ－２０００工作组讨论了一系列关于如何筹集电联活动经费的建议。ＩＴＵ－２０００工作组草拟的２０号建议如下：“建议电联委员会在产品和服务方面尽可能广泛…     

新业态 新技术 新挑战——2023年美国卫星大会见闻

<正>2023年3月13—16日，2023年美国卫星大会在华盛顿举办。美国卫星大会自1981年开始举办，是以卫星和太空技术产业为主题的年度重要展会。来自120个国家、超过12500人、300多家厂商参与，美国太空探索技术公司（SpaceX）、一网公司（OneWeb）、加拿大电信卫星公司（Telesat）、美国亚马逊公司（Amazon）等均参会。大会主要包含4个主题论坛，聚焦卫星技术、低轨卫星/小型卫星、军工、决策管理等方面。本次大会最重要且最受参会厂商关注的主题之一是卫星通信，除此之外，技术主题论坛还聚焦于软件驱动、太空计算、     

国际电联开会讨论静止卫星轨道和频谱规划问题

国际电信联盟(ITU,下称国际电联)定于1985年8月8日至9月13日在日内瓦召开《世界空间无线电行政大会》(下称《大会》),预计有一百多个国家出席。中国电信代表团由19人组成,将前往参加会议,团长为邮电部副部长朱高峰。根据国际电联1979年世界无线电行政大会的决议,此次《大会》将分两期举行:今年是第一期,将要决定关于制定静止卫星轨道和频谱规划的有关问题,包括规划方法、规划原     

让先进航天技术惠及人类社会——第六届航天技术创新国际会议在上海召开

<正>由中国宇航学会和国际宇航科学院联合主办的第六届航天技术创新国际会议于11月10日至11日在中国上海召开。本届会议的主题为"先进航天技术惠及人类社会"。共有来自14个国家的150多名代表参会。中国航天科技集团公司副总经理、本届会议地方组委会主席袁洁出席大会开幕式并代表集团公司董事长、本届大会主席雷凡培致辞,国际宇航科学院技术委员会主任菲利普·格拉扎     

把握航天发展脉搏 促进空间技术创新 首届空间科学与技术发展及应用学术大会召开

2014年8月18日,首届空间科学与技术发展及应用学术大会（以下简称首届大会）在北京召开。首届大会由中国宇航学会主办,中国航天科技集团公司钱学森空间技术实验室承办,主题为＂空间信息系统及有效载荷技术＂。大会学术委员会、国家各部委、中国科学院及相关科研机构和高等院校的院士、领导、专家、学者、科技人员等共400多人出席了首届大会。     

中国空间探测活动回顾

“十二五”期间,我国空间探测活动取得了突出成就。嫦娥－2绕月探测器开展了多项拓展试验,包括探测了图塔蒂斯（Toutatis）小行星;嫦娥－3落月探测器首次实现了我国对地球以外天体的软着陆,使我国成为世界上第三个掌握落月探测技术的国家,同时进行了就位探测和巡视探测,工程和科学成果双丰收;探月工程三期再入返回飞行试验器（简称试验器）的返回器顺利着陆,表明我国已全面突破和掌握航天器以接近第二宇宙速度的高速再入返回关键技术,其服务舱进行了多项重要的拓展试验。     

第47届国际宇航联大会在京举行

今年１０月７日～１１日，在北京举行了第４７届国际宇航联（ＩＡＦ）大会。这是ＩＡＦ大会首次在中国召开。来自世界５０多个国家和地区的１２００余名宇航专家、学者和政府官员（正式代表）出席了开幕式，江泽民主席在开幕式上发表了重要讲话。１０月８日，李鹏总理会见...     

1988年世界无线电行政大会概况

1988年8月29日至10月6日在日内瓦国际电联总部召开了地球静止卫星轨道利用和规划的世界无线电行政大会,简称WARC-ORB(88)。会上,制定了卫星固定业务在扩展频段上的分配规划及其实施程序,并研究讨论了其它有关事宜。规划将于1990年7月1日起生效,有效期至少20年。     

第65届国际宇航大会在加拿大召开

2014年9月29日-10月3日,第65届国际宇航大会（IAC）在加拿大多伦多召开。本届会议的主题是＂世界需要航天＂。3200多名来自世界各地的航天界官员、航天企业领导、科研人员、大学教师等代表出席了这届大会,其中有69个国家的代表向会议提交了论文。会议举办了7场全体大会、3场亮点报告、3场最新进展报告、181个技术分组会议、32个研讨会,主要涵盖了空间科学与探测,空间应用与操作。     

Research on the Relation Between the Seeker's Handover and the Geometrical Position of the Missile and the Target

 研究了雷达导引头的交班误差以及截获概率与交班时刻弹目几何位置的关系,提出了单个误差角的导引头天线指向角误差模型,它与两个误差角的导引头指向角误差模型相比可以更好地分析天线指向角误差,并得到使指向角误差最小的弹目几何位置;然后进一步得到使多普勒频率误差最小的弹目几何位置;给出了最终的截获概率的表达式,截获概率由目标处于导引头天线主波束的概率、目标回波多普勒频率落入接收机频带内的概率和目标的检测概率组成的;最后分析了一种典型的中末交班情况.     

火星地形对火星大气运动的影响及火星尘暴发生的可能机制

本文在准地转模式的假定下,讨论了火星地形对火星大气的影响,并根据文章所提供的信息对火星尘暴发生的物理机制作了粗略的解释。      

Comparison of the magnetic field before the subsolar magnetopause with the magnetic field in the solar wind before the bow shock

Crossings of the magnetopause near the subsolar point are analyzed using data of THEMIS mission. Variations of the magnetic field near magnetopause measured by one of THEMIS satellites are studied and compared with simultaneous measurements in the solar wind by another THEMIS satellite. The time delay of the solar wind arrival at the subsolar point of the magnetopause is taken into account. 30 and 90 s averaging of the magnetic field in the magnetosheath is produced. The results of averaging are compared with the results of measurements in the solar wind before the bow shock and foreshock. It is shown, that _Bx$B_x$ component of the magnetic field near magnetopause is near to zero, which supports the possibility to consider the magnetopause as the tangential discontinuity. Comparatively good correlation of _By$B_y$ component in the solar wind and near the magnetopause is observed. The correlation of _Bz$B_z$ component near the magnetopause and IMF is practically absent, the sign of the _Bz$B_z$ near the subsolar point does not coincide with the sign of IMF _Bz$B_z$ in ∼$\sim$30% cases.     

陀螺仪短周期性能测试方法研究

讨论了陀螺仪短周期重复性能的标定测试方法,即极轴翻滚试验方法。该方法以地球极轴为基准,通过对一周过程的电流值进行离散傅立叶分析,经过相应的运算处理求出误差模型参数的估计值。试验结果表明,该方法辨识参数多,全面反映了陀螺仪性能,可以科学地考察陀螺仪的短周期重复性。     

地磁暴恢复相中间层低热层高纬温度响应

利用TIMEGCM模拟了2005年9月10日至20日由日冕物质抛射引起的地磁暴事件,研究了此地磁暴恢复相高纬度中间层低热层（MLT）区域温度的变化,揭示了磁暴恢复相时温度、垂直风、总加热项和NO辐射冷却的内在联系.结果表明:地磁暴恢复相刚开始时,温度对磁暴的响应在晨侧为负扰动（降温）,在其他地区都为正扰动（增温）;随着磁暴的恢复,整个北半球都变为正的温度扰动（增温）.这种高纬MLT区域的温度响应主要与垂直风密切相关.当垂直风为正时,总加热为负,增温减弱;当垂直风为负时,总加热为正,增温变强.辐射冷却特别是NO辐射冷却作用在热层被称为恒温器,降低了磁暴期间80%的热层增温.但是,在MLT区域NO辐射冷却作用不明显,一般比总加热项小一个量级,对温度响应造成的影响较小.      

Method for the prediction of the effective dose equivalent to the crew of the International Space Station

This paper describes a methodology for assessing the pre-mission exposure of space crew aboard the International Space Station (ISS) in terms of an effective dose equivalent. In this approach, the PHITS Monte Carlo code was used to assess the particle transport of galactic cosmic radiation (GCR) and trapped radiation for solar maximum and minimum conditions through an aluminum shield thickness. From these predicted spectra, and using fluence-to-dose conversion factors, a scaling ratio of the effective dose equivalent rate to the ICRU ambient dose equivalent rate at a 10 mm depth was determined. Only contributions from secondary neutrons, protons, and alpha particles were considered in this analysis.     

Consequences of the application of the streamer fluid model to the study of the sprite inception mechanism

We present the results of a streamer-fluid model used to investigate the electrodynamical coupling between the troposphere and upper atmosphere due to the penetration of lightning electric fields into the mesosphere and the lower ionosphere, generating sprites. The model solves the continuity equation for electrons and ions coupled to Poisson equation. The dominant physical response of the atmosphere is the formation of a screening-ionization wave. The wave shields the atmosphere above it from the action of the lightning field and, together with the conductivity reduction below it due to attachment, the wave amplifies the total field below it, allowing for the penetration of intense electric fields in the mesosphere as it propagates downwards into regions of higher density that compress the wave. This is the key physical mechanism for sprite inception. We evaluated the effects of the thundercloud charge geometry, lightning current waveshape, atmospheric conductivity, via different electron density profiles, and the effect of ionization, attachment and electron mobility coefficients in the electrical breakdown process, related to halo production, and sprite streamer initiation. The results showed that electrons with higher mobility are more efficient in shielding the lightning electric field before breakdown, causing delay, and they contribute to the formation of the streamer seed after breakdown, anticipating the sprite streamer inception. Similarly, a higher effective ionization rate, produced by modifications in the attachment and ionization coefficients, anticipates sprite inception. The simulations with 6 different electron density profiles, and therefore conductivities, spanning 4 orders of magnitude, showed that the altitude of breakdown and sprite initiation, as well as their time delays from the lightning discharge are directly related to atmospheric conductivity: higher conductivities produce halo and sprite inception at lower altitudes with longer delays and may hinder sprite formation. We document that variations of 30 times in the lightning current leads to sprite initiation altitudes in the range 66.0–73.5 km, with delays between 1.550 and 34.500 ms, while variations of 4 orders of magnitude in the conductivity profile lead to initiation altitudes 61.0–70.6 km, with delays in the range 3.825–9.825 ms. Consequently, we suggest that lightning characteristics dominate over atmospheric parameters in determining sprites’ initiation altitude and delay. The simulation of a −CG, with a constant current of 30 kA, did not produce a sprite seed, confirming an asymmetry in the response of the atmosphere to positive and negative lightning. This is due to the free electron drift direction that is away from the screening ionization wave, preventing the formation of the streamer seed for the great majority of −CGs. The same does not apply to halos, which depend on the occurrence of breakdown and can be produced by discharges of both polarities.     

Influence of the Ionosphere on the Observation of the Mid-Latitude Pi2 Pulsations at the Global Scale

Results of our investigation showed that occurrence frequency of Pi2 over a 24 hour period undergoes seasonal variations in time coincidence with foF2. In the winter months, at sunrise and sunset (when foF2gradients are the largest) the observation probability of these oscillations is minimal. At periods of summer solstice when the F2-layer persists almost round the clock, no effect of Pi2 pulsation attenuation is observed at sunrise and sunset. The pulsation amplitudes behave in a similar manner. Results of this study suggest the conclusion that the propagation of signal from the Pi2 sourse into the mid-latitudes, and also the parameters of these pulsations are essentially affected by electron density in the ionospheric F2-layer.      

On the correlation of the solar wind observed at the L5 point and at the Earth

The L5 point is a promising location for forecasting co-rotating high-speed streams in the solar wind arriving at the Earth. We correlated the solar wind data obtained by the Nozomi spacecraft in interplanetary space and by the Advanced Composition Explorer (ACE) at the L1 point, and found that the correlation is significantly improved from that of the 27-day recurrence of ACE data. Based on the correlation between the two spacecraft observations, we estimated the correlation of the solar wind velocity between the L5 point and at the Earth, and found that the correlation coefficient was about 0.78 in late 1999, while that of the 27-day recurrence was 0.51. Eighty-eight percent of the velocity difference falls within 100 km/s between the L5 point and the Earth. This demonstrates the potential capability of solar wind monitoring at the L5 point to forecast the geomagnetic disturbances 4.5 days in advance.     

辐射变色薄膜剂量计性能测试及加速器应用

本课题的目的是建立用于辐射加工高剂量水平吸收剂量测量的辐射变色薄膜剂量计。通过系统研究,批量制备了以尼龙为基材,副品红氰化物为染料的辐射变色薄膜剂量计。为了验证批制辐射变色薄膜剂量测量的可靠性,选择了国际上应用较广的FWT-60膜及丙氨酸薄膜剂量计与本实验室批制的辐射变色薄膜开展实验室内剂量比对,比对结果均在±4%内符合,归一化偏差En绝对值均小于1。通过在加速器上进一步应用实验表明批制辐射变色薄膜可用于电子束辐照参数测量。