The Push for Development
The development of GPS came about out of necessity. As technology has advanced, GPS has also advanced to what we know it as today. We could not have a Global Position System without the advancement of rockets and satellites. Ironically we may owe a lot of this to the Soviet Union with them launching the first satellite and the cold war along with them shooting down civilian airliner KAL 007 in 1983 when it strayed in the Soviet Unions airspace. This pushed the United States to step up the pace to develop the Global Positioning System and for the first time is open to civilian use. Now GPS can be found in just about every facet of our lives, from driving navigation to outdoor uses, on job sites or in the mountains.
During WWII the military realized that they needed to find a better way to navigate than by the stars and weak or fading radio signals from radio towers. Many times when pilots were flying missions they would use radio signals to home in their home bases when they were returning home. This was fine if the pilot or navigator were near their planned return routes, but if they were off in their navigation to begin with they would have a hard time picking up the radio homing signal. They had to be within a given distance that was determined by the strength or power of the signal. In th early 1940s the LORAN system was in development for use for the military and used both on land and sea.
The First Big Break Through
When Sputnik was launched in 1957, a collection of United States scientists were monitoring its radio transmissions. They soon realized that Sputnik’s signal was higher on approach of the satellite and lower as the satellite had passed over and was moving away from them, because of Doppler effect. They theorized that if they knew what their fixed position was on the earth that they could figure out the exact position of the satellite by measuring the Doppler distortion or figuring where the satellite was in its orbit from their ground position.
The US Navy was the first to successfully test a satellite navigation system in 1960, it was known as Transit. This system was based on a constellation of five satellites orbiting the earth. The draw back to this system was that you could only get a navigation fix once an hour. In order for GPS to ever work they needed to have reliable accurate clocks in space. The US Navy once again stepped forward by launching the Timation satellite in 1967 which accomplished this.
The first world wide ground, based radio navigation system became operational in the 1970’s. It was known as The Omega Navigation System, but it was based on a single phase comparison.
In early 1978 another experimental line of GPS satellites known as Block-I was launched, with ten more to follow that would be launched by 1985. Modern Block-II satellites were beginning to be launched by early 1989 to start to replace and enhance the Block-I system already in place. By December 1993 the finally attained operational capability, and a complete constellation of 24 satellites were in place by January 1994. The oldest operational satellite in the system was launched in early 1989, with the newest satellite being launched in September of 2006.
After the Soviet shooting down of the Korean airliner KAL 007 in 1983, President Ronald Regan announced that the civilian population would have access for use to the GPS navigation system once it was completed. During President Bill Clinton’s administration the government realized the importance of the GPS system to civilian users as well as the military. Clinton then created the Interagency GPS Executive Board to administer and over see the Global Positioning System. At this point GPS really became a dual-use system for both civilian and military use. In 1998 then Vice President Al Gore announced future plans for an upgrade to the GPS system to include two new signals for civilian use, in point for aviation use and safety, and to enhance the reliability and accuracy of the system. In 2004 with an updated national policy President George W. Bush announced that the Interagency GPS Executive Board would be replaced by the National Space- Based Positioning, Navigation, and Timing Executive Committee because of the importance of the GPS system to us in our everyday lives.
With the rapid advancement of technology in today’s world there will be many changes in the GPS industry. We will find it more and more intertwine with our lives as more uses are developed for it.
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