History of GPS Technology

As the industrial revolution gained momentum in the early 20th century, there emerged a need for improving the navigations systems used in global trade. Utilizing radio technology, a series of navigation systems, such as LORAN, were based on low-frequency. Such waves which lacked the pinpoint accuracy needed to truly providing positioning guidance beyond the existing methods of triangulation. A series of scientists developed a theoretical framework for a satellite-based navigation system during the Second World War, which started to become a reality when the USSR launched Sputnik in October of 1957.

With the launch of the first satellite, scientists at MIT quickly determined they could track satellites by recording changes in the radio signal emitted from the vessel, which became known as the Doppler Effect. Based on this insight, the US Military began to develop satellite-based navigation technology that would evolve into the Global Positioning System, or GPS.

The first implementation of the technology, known as the Transit System, tracked nuclear submarines using five orbiting military satellites. Based on measurements of the Doppler shift, the system had a high level of accuracy but had a lag that prevented real-time tracking. In the 1960s, the US Navy developed the technology to allow satellites to keep precise time measures, which allowed for improvements in accuracy readings. Seeking a higher level of tracking precision, the Department of Defense developed the Navstar Global Positioning System (NAVSTAR-GPS), which became the first phase of GPS, in the 1970s. The project launched several satellites in the late 1970s, which grew to a full 24 orbiting satellites by the 1990s.

Several enhancements to GPS have been developed, known as Global Navigation Satellite System (GNSS) Augmentation technologies. In addition, several countries are developing their own proprietary satellite navigation technology include the the European Union (EU) Galileo navigation system, Russia's GLONASS project, China's COMPASS Navigation and India's IRNSS.

Bradley E. is a technology editor at iRevewer, a leading reviews site. Find GPS Reviews at iRW.com.

AP - The war of words waged by John McCain and Barack Obama for the votes of plumbers and other average Joes is a reminder of the nation's long-standing doubts about concentrated wealth - and its qualms about doing something about it.