Finding the way home
Hundreds of years ago, travellers found their way by looking at the stars. They built towers that could be seen from far, made maps and invented the compass.
Nowadays, almost every explorer and mountain climber uses the Global Positioning System (GPS) to make their journeys safer. There are even plans to put GPS receivers on all the taxis in Beijing in time for the 2008 Olympics. Finding your way has never been so easy.
Technology has changed our lives: for less than 500 yuan, you can get a pocket-sized GPS gadget that will tell you exactly where you are on Earth at any moment.
When people talk about a GPS, they usually mean a GPS receiver. The GPS is actually a set of 27 Earth-orbiting satellites-24 in operation and three extras in case one fails.
The US army developed this satellite network as a military navigation system in the 1970s, but opened it up to business use in the 1990s.
A GPS receiver locates these satellites, records the distance to each, and uses the information to calculate the receiver's exact position on Earth.
數(shù)百年前，旅行的人通過觀察天上的星斗來識路。他們建造從遠處就能看得見的燈塔，繪制地圖，并發(fā)明了指南針。
現(xiàn)在，幾乎每個探險家和登山者都使用全球定位系統(tǒng)（GPS）以確保旅行更安全。為了2008年奧運會，北京甚至計劃在所有的出租車上安裝GPS接收器。位置識別從來沒有象現(xiàn)在這樣容易。
技術(shù)改變了我們的生活。你只需花費不到500元錢，就能買到一個口袋兒大小的GPS部件，可以精確地告訴你某個時刻到底處于什么位置。
人們在談到GPS時，指的通常是GPS接收器。實際上，GPS是一組由27個環(huán)地球軌道運行的衛(wèi)星組成的衛(wèi)星網(wǎng)絡(luò)，其中包括24個處于運行狀態(tài)的衛(wèi)星和3個額外的備用衛(wèi)星。
該衛(wèi)星網(wǎng)絡(luò)是美國軍隊于20世紀70年代開發(fā)出來作為軍事導航系統(tǒng)的，在90年代開放作商業(yè)用途。
GPS接收器對這些衛(wèi)星進行定位，記錄下到每個衛(wèi)星的距離，并使用這些信息來計算接收器所處的具體方位。
Hundreds of years ago, travellers found their way by looking at the stars. They built towers that could be seen from far, made maps and invented the compass.
Nowadays, almost every explorer and mountain climber uses the Global Positioning System (GPS) to make their journeys safer. There are even plans to put GPS receivers on all the taxis in Beijing in time for the 2008 Olympics. Finding your way has never been so easy.
Technology has changed our lives: for less than 500 yuan, you can get a pocket-sized GPS gadget that will tell you exactly where you are on Earth at any moment.
When people talk about a GPS, they usually mean a GPS receiver. The GPS is actually a set of 27 Earth-orbiting satellites-24 in operation and three extras in case one fails.
The US army developed this satellite network as a military navigation system in the 1970s, but opened it up to business use in the 1990s.
A GPS receiver locates these satellites, records the distance to each, and uses the information to calculate the receiver's exact position on Earth.
數(shù)百年前，旅行的人通過觀察天上的星斗來識路。他們建造從遠處就能看得見的燈塔，繪制地圖，并發(fā)明了指南針。
現(xiàn)在，幾乎每個探險家和登山者都使用全球定位系統(tǒng)（GPS）以確保旅行更安全。為了2008年奧運會，北京甚至計劃在所有的出租車上安裝GPS接收器。位置識別從來沒有象現(xiàn)在這樣容易。
技術(shù)改變了我們的生活。你只需花費不到500元錢，就能買到一個口袋兒大小的GPS部件，可以精確地告訴你某個時刻到底處于什么位置。
人們在談到GPS時，指的通常是GPS接收器。實際上，GPS是一組由27個環(huán)地球軌道運行的衛(wèi)星組成的衛(wèi)星網(wǎng)絡(luò)，其中包括24個處于運行狀態(tài)的衛(wèi)星和3個額外的備用衛(wèi)星。
該衛(wèi)星網(wǎng)絡(luò)是美國軍隊于20世紀70年代開發(fā)出來作為軍事導航系統(tǒng)的，在90年代開放作商業(yè)用途。
GPS接收器對這些衛(wèi)星進行定位，記錄下到每個衛(wèi)星的距離，并使用這些信息來計算接收器所處的具體方位。