GPS
Made by 覃岚
蒋若茹
赖信
君
谢 海莹
Question 1
What’s GPS short for?
Global Positioning System.
Are you familiar to GPS? And how much do you know about it?
Well, let’s introduce it to you. GPS, is the only fully-functional satellite navigation(导航) system. More than two dozen GPS satellites broadcasts precise timing signals by radio to GPS receivers, allowing them to accurately determine their location in any weather, day or night, anywhere on Earth.
The History Of GPS
February
1978 ，The GPS satellites
In
1983, after Soviet interceptor aircraft
By 1985, more experimental Block-I satellites .The first
modern Block-II satellite .
In 1992, the 2d Space Operations Squadron
by December 1993 A complete constellation of 24
satellites
In 1996, a policy
In 1998, upgrade GPS
In 2004, updated the national policy.
September 2005. The most recent launch
Although GPS is a system of new technology, it develops so fast.
The United States Department of Defense developed the system, officially named NAVSTAR GPS ,and launched the first experimental satellite in 1978.
Over fifty GPS satellites such as this NAVSTAR have been launched since 1978.
In late 2005, the first in a series of nextgeneration GPS satellites was added to the constellation, offering several new capabilities, including a second civilian GPS signal called L2C for enhanced accuracy and reliability. In the coming years, additional next-generation satellites will increase coverage of L2C and add a third and fourth civilian signal to the system, as well as advanced military capabilities.
Question 2
Which fields can GPS be used in? Military Navigation Mobile Satellite Communications Location-based services Location-based games Aircraft passengers
GPS used in
navigation
This is a taxi in Tokyo, equipped with GPS navigation. This is an example of how GPS technology applied in routine activities.
GPS used in Location-based
games
GPS receivers come in a variety of formats(形 式), from devices integrated（综合的） into cars, phones, and watches, to dedicated devices such those shown here from manufacturers Trimble, Garmin and Leica (respectively, left to right).
GPS used in Aircraft
passengers
Even fixed systems may use GPS, in order to get precise time. This antenna is mounted on the roof of a hut containing a scientific experiment needing precise timing.
Except for GPS, there are another systems for global positioning…
Russia operates an independent system
called GLONASS although with only twelve active satellites as of 2004, the system is of limited usefulness. Availability in Russia, Northern Europe and Canada is above 90%. Meaning that at least 4 satelites are visible 90% of time, which is notable considering GLONASS operates only 12 of 24 required satellites .
There are plans to restore GLONASS to full operation by 2008 with assistance from India. The
European Union is developing
Galileo as an alternative to USA owned operated GPS system. The People's Republic of China, Israel, India, Morocco, Saudi Arabia and South Korea joined the EU in this project. It is planned to be operational by 2010.
In one word, GPS has become a vital global utility, indispensable(不可缺少) for modern navigation on land, sea, and air around the world, as well as an important tool for map-making and land surveying. GPS also provides an extremely precise time reference, required for telecommunications and some scientific research, including the study of earthquakes.