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英语拓展阅读:全球定位系统

2012-03-03 07:30
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全球定位系统(Global Positioning System)

简单地说,这是一个由覆盖全球的24颗卫星组成的卫星系统。这个系统可以保证在任意时刻,地球上任意一点都可以同时观测到4颗卫星,以保证卫星可以采集到该观测点的经纬度和高度,以便实现导航、定位、授时等功能。这项技术可以用来引导飞机、船舶、车辆以及个人安全地、准确地沿着选定的路线,准时到达目的地。

全球定位系统(GPS)是20世纪70年代由美国陆海空三军联合研制的新一代空间卫星导航定位系统 。其主要目的是为陆、海、空三大领域提供实时、 全天候和全球性的导航服务,并用于情报收集、核爆监测和应急通讯等一些军事目的,是美国独霸全球战略的重要组成。经过20余年的研究实验,耗资300亿美元,到1994年3月,全球覆盖率高达98%的24颗GPS卫星星座己布设完成。

对目的地及周边环境的精准查询需求带动了GPS导航产品市场的繁荣。据相关统计,欧美国家导航设备普及率达到90%,日本更是超过95%。一项对3G应用的展望和创意的专业调查显示,17.79%的被调查者选择了3G网络视频对话,15.34%的被调查者选择了GPS/地图搜索,在3G时代来临之际,人们对GPS/电子地图的关注,足以显现它在日常生活中的重要性。

拓展阅读:

Mr. Perkin's New Car

Mr. Perkin stood at the bus-stop and watched the cars go by. Many of the cars were new Beta 400s, and most of them were yellow. Mr. Perkin always wore the same clothes as other men, ate the same food as other people, and did the same things after work, and at the end of the week, Mr. Perkin did not like to be different.

The following week, Mr. Perkin bought a new, bright yellow Beta 400s. He was satisfied with it, and drove it to work in the very next day. He was even more satisfied with his new car, when he saw all the other Beta 400s, in front, behind, and on both sides of him.

Mr. Perkin parked his car in a big car-park near his office, and walked the rest of the way. But when he came back at five o'clock, there were so many bright yellow Beta 400s. He tried his key in some of the cars, but people passing by gave him a look he didn't like. So he stopped. Poor Mr. Perkin had to wait nearly two hours until his was the only yellow Beta 400s in the car-park.

1. Mr. Perkin bought a new, bright yellow_______.

A. Beta 600s B. Beta 400a C. Beta 400s D. Beta 600a

2. Mr. Perkin did not like to be_______.

A. different B. foolish C. strange D. fashionable

3. Poor Mr. Perkin had to wait ______hours until found his car.

A. two B. nearly two C. three D. five

4. Why does Mr. Perkin want a new yellow Beta 400s?

5. How did Mr. Perkin find his car?

答案:

1. C

解析:Mr. Perkin bought a new, bright yellow Beta 400s 选C

2. A

解析:Mr. Perkin did not like to be different. 选A

3. B

解析:Poor Mr. Perkin had to wait nearly two hours until his was the only yellow Beta 400s in the car-park 选B

4. (Because he likes to do the same things as other people.)

解析:Mr. Perkin did not like to be different.

5. (Mr. Perkin couldn't find his car until his was the only yellow Beta 400s in the car-park.)

解析:Poor Mr. Perkin had to wait nearly two hours until his was the only yellow Beta 400s in the car-park

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