Download
In November 1993, student Jennifer Koon was kidnapped and killed in New York state in the United States.
Before her death, the 18-year-old college sophomore and daughter of a New York state assemblyman managed to call 911, but police could not determine her position from the cellphone signal.
Three years later, the public safety network Location-based Services was established, allowing authorities to locate users through radio signals.
Now, in China, nearly two decades later, such services are not far away.
"LBS is nothing new. The reason we could not develop an LBS in China until now is that the Internet on mobiles only became popular in the past few years," said Shi Chuang, a professor at Wuhan University and director of the National Engineering Research Center for Satellite Positioning System.
"With LBS, we can integrate information on people ... and things, so that we can dig out business value," he said.
As a result, life can be made more convenient, such as through live monitoring of traffic congestion or monitoring dangerous and poisonous goods.
However, nothing can be accomplished without a highly accurate positioning system.
Paul Zandbergen, an associate professor at the University of New Mexico's geography department, did an accuracy survey on positioning systems on the 3G iPhone in 2009.
Results showed Wi-Fi locations using this phone had an average error of 74 meters for 58 observations, failing to meet the published accuracy specifications, while cellular positioning using this phone had a median error of 600 meters for 64 observations.
"Most pointing devices can pinpoint positions within 10 meters. But if we can improve the accuracy to less than a meter, it means we can accomplish many tasks that were not possible without a high-accuracy system," Shi said.
On Oct 9, China's National Remote Sensing Center said a new navigation system, Xihe, had been successfully tested to pinpoint positions within 0.1 meters outdoors and 3 meters indoors.
The system benefits business owners like Cao Hongjie, vice-president of Beijing UniStrong Science and Technology, a maker of navigation products.
"In the past, we designed different circuit boards for clients having different demands for the precision, but with Xihe, the precision difference can be controlled in operation centers, and we can use a device that applies to Xihe to provide services with different accuracy," Cao said.
For example, during China's last land survey, UniStrong designed several devices because accuracy requirements in eastern and western parts of the country vary by up to 50 times.
Cao said the device that sold best and cost 15,000 yuan ($2,400) had an error factor of less than 5 cm. "But now I have developed a new version of the land survey device using the Xihe system, which is as good as the former and I'm planning to sell it for up to 8,000 yuan," he said. "The new technology lowers the price, but gives me even more room for profit."
Questions:
1. What technology can help public safety?
2. What are some practical applications?
3. How accurate is the system?
Answers:
1. Location-based Services using radio signals.
2. Live monitoring of traffic congestion or monitoring dangerous and poisonous goods.
3. Most pointing devices can pinpoint positions within 10 meters.
About the broadcaster:
Nelly Min is an editor at China Daily with more than 10 years of experience as a newspaper editor and photographer. She has worked at major newspapers in the U.S., including the Los Angeles Times and the Detroit Free Press. She is also fluent in Korean.
严重期待《盗梦空间》的七个理由
《纳尼亚传奇3:黎明踏浪号》片段之Fairy Tale
《绯闻女孩》第四季:小J回归!!
那些美貌与智慧并存的美女演员兼导演
《绯闻女孩》第四季剧透:Queen B归来!!
看12部传世电影 学习真正的浪漫
好莱坞恐怖片12大绝色美女主角
10部经典电影让你看透女人心
纽约被电影预言的九种毁灭方式
《暮光之城》电影讲解(52):我会不惜一切代价保护你
好电影+好主题曲的12个经典绝配
《绯闻女孩》会来中国取景吗?
即将上映之英国篇:这十部可能是好电影
青春偶像个个数 好莱坞新生代集体演公益广告
十大最该分手的美剧情侣
电影中时间旅行的N种方法
《暮光之城》电影讲解(53):我从未想过我会如何死去
《绯闻女孩》片场潮人聚集 梅斯特中性莱弗利性感
《绯闻女孩》:Blake Lively没有要求离开剧组
不可不看的8部澳洲小众电影
暑期必看的的22部新片
胶片跳动三分钟:品味二十三段绝妙开场戏
青少年选择奖颁出 《吸血鬼日记》《新月》成赢家
华纳推出DC漫画纪录片 讲述超级英雄诞生史
10部激起时尚灵感无限的影片
电影与时尚完美结合的11部电影
十三部高智商电影 你看过几部?
影史上最卖座的十部动画片
十佳经典英文电影译名
《八卦天后》莉顿-梅斯特新片剧照曝光
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |