When Was the Global Positioning System Invented?
The Global Positioning System became fully operational on April 27, 1995. Prior to that date, the long and complex process of launching and synchronizing satellites had been going on for years. Since the mid-1990s, GPS usage has spread widely and today millions of people use GPS navigation devices in their cars, aircraft, boats, or for any number of outdoor activities.
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Before GPS
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Prior to efforts toward building the GPS, the United States Navy produced the world's first satellite-based navigation system. Dubbed Transit, this system began with the launch of primitive satellites in the late 1950s. By the mid 1960s, Transit was operational and regularly used by Navy vessels. Transit relied on just five satellites and computing a ship's location took time, limiting its usefulness. Atomic clocks and advances in satellite technology led the military to look into a more sophisticated satellite navigation system, resulting in the proposal of the GPS.
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GPS Development
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Military testing of a new generation of navigation satellites began in the 1970s. Nearly a dozen test satellites had been successfully launched by the mid-'80s. One of the most significant events in the development of the GPS occurred when a commercial Korean Airlines flight was shot down by the Soviet Union after it entered restricted airspace due to a navigation error. With support from then-U.S. President Ronald Regan, it was decided that GPS would be available to civilian users, including airlines.
Completion of GPS
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The new satellites that would comprise the completed GPS were launched beginning in 1989. By the end of 1993, the system was functional but access remained controlled by the U.S. military. Early in 1994, the 24th satellite was added to the constellation, and extensive testing began. The Global Positioning System was declared operational in 1995. The next year, President Bill Clinton signed legislation mandating that it be made available to civilians as well as the military, with a provision that GPS signals could be scrambled or disabled by the military in cases of national emergency.
Evolution of GPS
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Having reached full operational capability, the GPS continued to be refined over the following decade. In 2000, the signal available to civilians was upgraded to match the quality of the military signal, making GPS navigation devices for cars much more practical. Since 2000, various companies have introduced GPS navigation devices with a host of features and user interfaces. GPS technology has also made its way to cell phones, automobile computers and PDAs. New and replacement satellites continue to be launched.
The Future
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In 2005, the launch of a new generation of GPS satellites with enhanced signal strength and accuracy began. Eventually these new satellites will replace the existing constellation of GPS satellites, some of which are nearly 20 years old. Russia's GLONASS satellite navigation system, which became operational in the 1990s and is available only to the Russian military, began extensive repairs and upgrades in 2001. In 1999, the idea of a European Union-backed satellite navigation system emerged. In 2003, it was formally agreed that European nations would work together on a project dubbed Galileo, which is currently in development with an estimated completion date of 2013.
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- Photo Credit Image by Flickr.com, courtesy of Gareth Simpson
