Achieving GPS–Galileo interoperability: the challenges ahead

The enormous benefits of a worldwide accurate location system can only be achieved if GPS and Galileo can be made truly interoperable. The technical issues involved are relatively easy to deal with but the political and legal problems require far greater attention, with military issues and enactment of legislation the chief difficulties. These are discussed using examples, notably from road traffic law. Given that the US DoD is unlikely to cede control of GPS to the civil sector and design a new, separate system, the best solution might be to set aside part of GPS for purely civil purposes.     

Space policy challenges facing the Barack Obama administration

President Barack Obama faces space policy challenges in security, commercial and civil areas in an era in which the use of space assets for these ends is irreversible. The very future of space is linked to addressing the challenges within the first term of the Obama administration. This paper draws on, but does not attempt to summarize, discussions at the National Space Forum 2008 organized by the Eisenhower Center for Space and Defense Studies at the United States Air Force Academy and the Center for Strategic and International Studies (CSIS) in Washington, DC. The goal of the forum was to examine the key decisions that will need to be made in regard to space policy by facilitating debate among the security, commercial and civil space sectors, and the broader national policy community. The paper focuses on choices which, for budgetary or other reasons, cannot be delayed. A brief discussion of the issues surrounding each choice is presented, followed by the implications of pursuing different choices. One key assumption underlies everything: resources available for activities in space will not grow significantly in real terms over the course of the Obama administration.     

Dreams and realities: the challenges facing development of space tourism

The era of public space travel is approaching faster than most people think, driven by the human desire for adventure, travel and fun, and by the economic motivation for creating a space industry. Before this will happen, advances in engineering, law and policy, and medicine must be made, as well as considering the issues involved in business and management. Public awareness of the possibility must be increased and world-wide excitement about space generated in order to make space tourism a reality. This is a slightly edited version of the executive summary of the design project produced by ISU students at their 2000 Summer Session Programme in Valparaiso, Chile.     

伽利略系统的频率结构和信号设计的研究

分析了伽利略系统的频率结构和信号设计、性能及干扰,阐明了伽利略系统的频率和信号设计比GPS更具优势。伽利略系统在ESa／L5和E2-L1-E1载波上,使用与GPS相同的中央频率,可提高GNSS接收机用户的互用性,因此具有更广阔的发展前景。     

Geometry-free linear combinations for Galileo

Global navigation satellites of the European Galileo system transmit code signals on four carriers in the L1, E5a, E5b and E6 band.New geometry-free linear combinations are presented that eliminate the geometry terms (user to satellite ranges and orbital errors), the clock errors of the user and satellites and the tropospheric delay. The remaining parameters of these carrier phase combinations include integer ambiguities, ionospheric delays, carrier phase multipath and phase noise. The weighting coefficients are designed such that the integer nature of ambiguities is maintained. The use of four frequency combinations is highly recommended due to a noise reduction of up to 14.4 dB and an ionospheric reduction of up to 25.6 dB compared to two frequency geometry-free combinations.Moreover, a modified Least-squares Ambiguity Decorrelation Adjustment (LAMBDA) algorithm is suggested, which differs in two points from the traditional approach: the baseline is replaced by the ionospheric delay and the correlation is caused by linear combinations instead of double differences. For correct ambiguity resolution, the ionospheric delay can be determined with millimeter accuracy. This is quite beneficial as the ionosphere represents the largest source of error for absolute positioning.     

伽利略光学实验分析

对伽利略光学实验进行了全面的分析,其中包括实验装置和元器件的分析,并重点分析了实验发射系统的工作原理和工作过程,对准、跟踪系统的工作原理和工作方式.并对实验的结果进行了详细分析,针对实验中出现的因大气影响而导致接收失败,讨论了采用自适应光学对大气影响进行补偿的方案的可行性,对于因背景光过强而导致的链路性能劣化,分析了采用干涉滤光片对背景光进行抑制的可行性,为我国将来开展深空光通信的研究提供参考.     

欧洲的伽利略卫星导航系统介绍

1999年欧洲委员会的报告对伽利略系统提出了两种星座选择方案:一是21+6方案,采用21颗中高轨道卫星加6颗地球同步轨道卫星。这种方案能基本满足欧洲的需求,但还要与美国的GPS系统和本地的差分增强系统相结合。二是36+9方案,采用36颗中高轨道卫星和9颗地球同步轨道卫星或只采用36颗中高轨道卫星。这一方案可在不依赖GPS系统的条件下满足欧洲的全部需求。该系统的地面部分将由正在实施的欧洲监控系统、轨道测控系统、时间同步系统和系统管理中心组成。为了降低全系统的投资,上述两个方案都没有被采用,其最终方案是:系统由轨道高度为23616km…     

伽利略计划简介

2003年5月26日,欧洲各国政府终于同意启动曾屡遭延迟的伽利略导航计划。伽利略计划是欧空局(ESA)和欧盟共同开展的第一个民用全球卫星导航系统项目。该计划被视为美国GPS全球卫星定位系统的潜在竞争对手。1999至2000年,在欧盟委员会与欧空局的领导下,欧洲从战略、经济、资金筹集、法规、用户需求和技术性能要求等方面对伽利略计划开展了一系列的研究。该计划的最终目标是建立一个独立的、性能优于GPS并与现有全球卫星导航系统(GPS和GLONASS)兼容的民用全球卫星导航系统。目前伽利略计划已经引起世界各国的极大关注。伽利略系统是欧…     

中国空间技术研究院全面展开伽利略计划合作项目

2006年3月23日，中欧合作项目——伽利略搜救系统前向链路服务端到端验证（EEV）和伽利略中轨卫星搜救接收站（ME—OLUT）合同签订仪式在北京友谊宾馆隆重举行。国家遥感中心主任张国成，中国伽利略卫星导航有限公司董事长孟波，科技部高新司副司长廖小罕，中国空间技术研究院的领导，欧空局副局长维利格里奥先生以及欧洲伽利略联合执行体（GJU）的代表参加了此次签字仪式。这标志着中欧在伽利略计划开发阶段的合作又前进了一大步。     

Talking space: The European Commission's changing frames in defining Galileo

This paper traces the way in which the European Commission has framed and reframed the issue of EU satellite navigation over 20 years. It investigates how the EU's agenda-setter has ‘talked about’ space policy, with a particular focus on Galileo, and how its own institutional discourse – as revealed in its communications throughout the agenda-setting stage of Galileo's ‘definition’ phase – evolved in the 1990s through the use of ‘frame sets’. In so doing, it illustrates the ways in which, over time, the EU's executive has ‘projected’ the issue of independent satellite navigation capabilities as being politically and economically desirable for Europe, and has sought to persuade decision makers of its cross-policy relevance and potential economic, social and security benefits. The article deconstructs official documents and engages in a close-up analysis of policy formulation, to identify nascent, evolving and mature frames in the definition of Galileo.     

Galileo导航卫星电源技术概述

继美国的GPS卫星导航系统和俄罗斯的GLONASS卫星导航系统之后,欧洲各国正在合作研制Galileo全球卫星导航系统。文章结合Galileo系统已经发射的两颗试验卫星,介绍了Galileo导航卫星的电源系统技术特点,并对其设计思路进行了分析,可为我国卫星电源系统设计所借鉴。     

打破美国垄断应用前景广阔欧洲"伽利略"导航卫星工程进入新阶段

2005年12月28日,欧洲“伽利略”卫星导航系统的首颗试验卫星由俄罗斯联盟FG火箭发射入轨。这是庞大的“伽利略”计划向前迈出的一大步,标志着该计划进入了真正的轨道验证阶段。     

2004年欧洲伽利略计划的若干重要进展

2004年是欧洲伽利略全球导航卫星计划取得重大进展的一年。在过去的一年中,欧美历经3年的艰苦谈判,终于在2004年6月签署了《关于促进、提供和利用伽利略与GPS卫星导航系统及其相关应用的协议》,从而为伽利略导航卫星系统的发展扫清了重重障碍。此外,伽利略计划在2004年还取得了如下重要进展。     

伽利略导航试验卫星电子系统设计概述

从2005年12月发射首颗试验卫星以来,欧洲伽利略卫星导航系统建设进入了新的阶段。GIOVE-A卫星平台和有效载荷电子设备的设计体现了当前先进的综合电子系统设计思想,卫星电子系统在集成化、模块化和网络化等方面具备了较高的技术水平。文章调研并分析了伽利略系统首颗试验卫星GIOVE-A的电子系统设计研制和在轨运行情况,可为我国全球导航卫星系统研制提供参考。     

中国航天参与中欧伽利略计划

10月19日．我国成功发射了风云2号C气象卫星。这次用于发射卫星的远地点发动机．是航天科技集团公司所属航天动力技术研究院(四院)经过10多年艰辛攻关研制成功的。东方红2号通信卫星的远地点发动机曾荣获国家金质奖．在我国的航天发射中屡建奇功。风云2号卫星的远地点发动机就是在该发动机研制成功的基础上研制的．1997年用于风云2号卫星的第一次发射．2000年6月参与风云2号B星的发射．为风云气象卫星的成功发     

伽利略系统对GPS的冲击及美国的应对措施

伽利略系统是欧洲的卫星无线电导航项目，它始于欧盟委员会的提案。并由欧洲空间局合作开发。目前，俄罗斯、中国、巴西、以色列等国家都参与了伽利略计划。伽利略系统作为新一代全球卫星导航系统，有利于发展新一代交通、电信、农业和渔业领域的通用服务，在未来卫星导航应用服务上发挥巨大作用。伽利略系统的总投资约34亿欧元，     

德公司赢得首批“伽利略”卫星建造合同

<正>欧盟委员会1月7日宣布了6项"伽利略"导航系统初步运行能力采购合同中3项的归属,称该系统将在2014年投入初步运行。正式合同将在未来数周内由欧空局代表欧委会同所选定的公司签署。"伽利略"项目分两个阶段实施。正在实施的在轨鉴定     

伽利略与GPS--导航之战

经过多年的争论，2003年春天欧空局和欧盟委员会终于同意了伽利略卫星导航定位系统的研制和未来部署计划。这一决定将在许多方面产生重大而深远的影响。本文将着重讨论伽利略计划在安全和防御方面的问题。     

欧洲伽利略卫星导航计划的应用及效益分析

伽利略（Galileo）计划是由欧盟提出的，由民用部门控制的卫星导航系统，是继已有的EGNOS欧洲静止轨道导航重叠服务）计划之后，欧洲朝着发展自己的卫星导航技术方向迈出的重要一步。伽利略系统是一种开放式系统，能够与GPS全球定位系统兼容，空间部分的核心星座计划由18～22颗卫星组成。系统建成以后，能够与新一代GPS系统一起构成本来的全球导航卫星系统（GNSS），向全球用户提供卫星导航信号。知利略系统的开发、建设及将来在各种领域的应用将为欧洲带来巨大的直接或间接效益，为21世纪欧洲工业界在高技术领域的发展提供重要机遇…