Global positioning technology (GPS) now present in most products such as navigation systems on cars, phones, devices handheld personal support …. But does not mean that we know all about this revolutionary technology.
At least 24 GPS satellites orbiting the earth, although this is more than 30 satellites, including two reserve satellites. Although anywhere on earth, also have at least six satellites in the region you stand.
- Each GPS satellite orbiting the earth once every 12 hours. The satellite flight distance 12.500 miles (20,000 km), averaging 7.000 miles per hour (about 11,000 km).
- To get the exact location and equipment of your GPS receiver to combine signals from four satellites, although in some special cases to just three.
- GPS was launched after a disaster. In 1983, 007 flights the airline Korean Air Lines had violated Soviet airspace after an equipment guide and damaged aircraft was shot down along with all 269 passengers died. The consequences of this accident that U.S. President Ronald Reagan ordered the military to produce a global positioning system for civilian purposes was completed to avoid similar accidents.
- NavStar starting point is the name given to the U.S. military global positioning system.
- GPS is not just for navigation but it also can be used to obtain accurate time. Each GPS satellite has atomic clocks and time signals are sent with them sent. With support from the signals, a GPS receiving device can determine the current time in 1 / 100 billion seconds. These signals are used to synchronize the time on your cell phone.
- The ground antennas spread throughout the world are used to adjust the path of the satellite and the time they sync.
- GPS is owned and placed under the control of the Department of Defense.
- By 2000, civilian GPS has removed a feature called “choice is available” (Selective Availability – SA). This causes a random error of up to 328 feet (about 100) to reduce the accuracy of the navigation (GPS signal is the difference in purpose military and civilian). SA feature turned off on 01/05/2000.
- During the Gulf War in 1991, many U.S. soldiers are equipped with GPS devices and functions of the SA was turned off during the war.
- GPS is a work session. The system was further upgraded and the addition of new satellite. This means the accuracy will increase and the system will become more useful.
(source:news.ictexpress.com)
