Google is expanding into alternative energy in its most ambitious effort yet to ease the environmental strain caused by the company`s voracious appetite for power to run its massive computing centers. (Nov. 28)
(Los Angeles) The blaze began at Corral Canyon Road. Juan Fernandez reports.
(Los Angeles) Certain neighborhoods of Malibu were hardest hit this time around. Josh Rubenstein reports.
Global Positioning SystemFrom Wikipedia the free encyclopedia (Redirected from Gps)GPS redirects here For other similar systems see Global Navigation Satellite System For other uses of GPS see GPS (disambiguation)For a generally accessible and less technical introduction to the topic see Introduction to the Global Positioning SystemArtists conception of GPS satellite in orbitCivilian GPS receiver (GPS navigation device) in a marine applicationAutomotive navigation system in a taxicabThe Global Positioning System (GPS) is a Global Navigation Satellite System (GNSS) developed by the United States Department of Defense It is the only fully functional GNSS in the world It uses a constellation of between 24 and 32 Medium Earth Orbit satellites that transmit precise microwave signals that enable GPS receivers to determine their current location the time and their velocity Its official name is NAVSTARGPS Although NAVSTARGPS is not an acronym1 a few backronyms have been created for it2 The GPS satellite constellation is managed by the United States Air Force 50th Space Wing GPS is often used by civilians as a navigation systemSimilar satellite navigation systems include the Russian GLONASS (incomplete as of 2008) the upcoming European Galileo positioning system the proposed COMPASS navigation system of China IRNSS of India and DORIS of FranceAfter Korean Air Lines Flight 007 was shot down in 1983 after straying into the USSRs prohibited airspace3 President Ronald Reagan issued a directive making GPS freely available for civilian use as a common good4 Since then GPS has become a widely used aid to navigation worldwide and a useful tool for mapmaking land surveying commerce scientific uses and hobbies such as geocaching Also the precise time reference is used in many applications including scientific study of earthquakes and synchronization of telecommunications networksThe first satellite navigation system Transit used by the United States Navy was first successfully tested in 1960 Using a constellation of five satellites it could provide a navigational fix approximately once per hour In 1967 the US Navy developed the Timation satellite which proved the ability to place accurate clocks in space a technology the GPS relies upon In the 1970s the groundbased Omega Navigation System based on signal phase comparison became the first worldwide radio navigation system The design of GPS is based partly on similar groundbased radio navigation systems such as LORAN and the Decca Navigator developed in the early 1940s and used during World War II Additional inspiration for the GPS came when the Soviet Union launched the first Sputnik in 1957 A team of US scientists led by Dr Richard B Kershner were monitoring Sputniks radio transmissions They discovered that because of the Doppler effect the frequency of the signal being transmitted by Sputnik was higher as the satellite approached and lower as it continued away from them They realized that since they knew their exact location on the globe they could pinpoint where the satellite was along its orbit by measuring the Doppler distortion
