完形填空satellite navigation system
China is to contribute to a new global satellite navigation system being developed by European nations. The Galileo satellite system 1 will offer a more accurate civilian alternative to the Global Positioning System(GPS)， operated by the US military. China will provide 230m Euros (USD 259m) in 2 funding and will cooperate with technical， manufacturing and market development. “China will help Galileo to 3 become the major world infrastructure for the growing market for location services，” said Loyola de Palacio， EU transport commissioner.
A new center that will coordinate co-operation was also announced 4 by the European Commission， the European Space Agency (ESA) and the Chinese Ministry of Science and Technology not long 5 ago 。The China-Europe Global Navigation Satellite System Technical Training and Cooperation Center will be 6 located at Beijing University. China has a substantial satellite launch industry and could potentially help the Galileo satellites.
The US has claimed that Galileo could interfere 7 with the US ability to downgrade the GPS service during military conflicts. European officials say this is unfounded and counter that US opposition 8 is due to the commercial challenge Galileo would present to GPS. Galileo will be precise to within a meter， while civilian GPS service is accurate to around 10 meters.
The Galileo satellite constellation will 9 consist of 27 operational and three reserve satellites orbiting the Earth at an altitude of 23， 600 km. The satellites will be strung along three medium-Earth orbits at 56 degrees inclination to the equator and will provide global coverage. The system should be operational by 2008 and the entire project is expected to 10 cost around 3.2 billion Euros(USD 3.6 billion)。
The European Commission has said Galileo will primarily be used for transportation technology， scientific research， land management and disaster monitoring.
Galileo will provide two signals; a standard civilian one and an encrypted， wide-band signal 11 called the Public Regulated Service (PRS)。 This second signal is designed to withstand localized jamming and will be used by police and military services in Europe. European Commission __12_officials_ have said China will not be given access to the PRS.
The first Galileo satellite is scheduled to launch late in 2004， Clocks on board the 13_satellite_ Will be synchronized through 20 ground sensors stations， two command centers and 15 uplink stations.
Receivers on the ground will use time signals from the satellites to precisely calculate their 14 location 。 A “search and rescue” function will also 15 let distress signals be relayed through the constellation of satellites.
中国帮助欧洲发展全球定位系统的竞争 (B)
中国要捐助欧洲国家正在开发的全新的全球卫星定位系统。伽利略人造卫星系统将提供了一个较美国军事机构使用的全球定位系统更为精确的民用系统。中国将提供两亿三千万欧元（两亿伍千九百万美元）的资金，并且协助技术、制造以及市场拓展的开发。欧洲交通委员罗瑶拉德帕若索说：“中国将帮助伽利略（人造卫星）成为成长中的定位服务市场的主要世界基础设施。”
不久前，欧洲贸易委员会、欧洲航天局和中国科技部还宣称将建立一个新的中心来协助合作。中国——欧洲全球定位卫星系统技术培训和合作中心将座落于北京大学。中国具有一个非常有实力的卫星发射工业。有可能帮助发射伽利略卫星。
美国声称伽利略会在军事斗争中干扰美国的能力并消减全球定位系统的使用。欧洲官员称这种说法无事实根据，并对美国所谓的伽利略（人造卫星）会对全球定位系统的商业上构成挑战的说法持反对意见。伽利略（人造卫星）将精确到一米，而民用全球定位服务只精确到10米。
伽利略人造卫星群由27个运用卫星和3个储备卫星构成，并在地球表面23 600千米的高度运行。卫星将与三个中等地球轨道并排在与赤道56度的倾斜角度上运行，并且可以覆盖全球。这个系统将在2008年启动，整个项目将耗资32亿欧元（36亿美元）。
欧洲贸易委员会说伽利略（人造卫星）最初将被用于交通技术、科学研究、陆地管理和自然灾害监控两种信号：一种是加密信号，称为标准民用信号，另一种是公共调控服务系统加密信号。第二种信号是为抵抗地方交通堵塞而设计的，将被用于欧洲公安和军事事业。欧洲贸易委员会官员说中国将无权使用公共调控服务系统。
第一个伽利略人造卫星将在2004年底发射。这架卫星上的钟表将与20个地面感应站、2个指挥中心和15个上行站时间同步。
地面的接收器将利用卫星上的时间信号准确地计算出它们的方位。“搜索救援”功能也会通过卫星群传递遇难信号。