GPS design partly originated from ground-based radio navigation systems developed in the early 1940s, which were utilized during World War II. These systems, named LORAN and Decca Navigator, were primarily focused on locating the enemy to either engage or retreat strategically based on the size of the forces.
Additional inspiration for modern GPS systems came when the Soviet Union launched Sputnik in 1957. A team of scientists monitored Sputnik’s radio transmissions and discovered that due to the Doppler Effect, the frequency of the signal was higher as the satellite approached and lower as it moved away. The Doppler Effect is the change in frequency and wavelength of a wave as perceived by an observer moving relative to the source of the waves.
This team of scientists soon realized that they could pinpoint the satellite’s location along its orbit by measuring the Doppler distortion, as long as they knew their exact location on the globe. This realization was groundbreaking and highly exciting for the military.
The United States Navy employed the first satellite navigation system called Transit, which was successfully tested in 1960. Using a constellation of five satellites, they discovered the system could provide a navigational fix approximately once per hour.
In 1967, the Navy developed the Timation satellite, proving the ability to place accurate clocks in space, a cornerstone technology for GPS systems. In the 1970s, the ground-based Omega Navigation System, based on signal phase comparison, became the first worldwide radio navigation system.
In February 1978, the first experimental Block-I GPS satellite was launched, marking the beginning of modern GPS system development. Originally made by Rockwell International, the current satellites are manufactured by Lockheed Martin.
By 1985, ten more experimental Block-I satellites had been launched to validate the GPS concept. The first modern Block-II satellite was launched in 1989, and by December 1993, the GPS system achieved initial operational capability. By April 1995, a complete constellation of 24 satellites was in orbit with full operational capability declared by NAVSTAR.
A year later, President Bill Clinton recognized the importance of GPS for civilian use as well as military use, issuing a policy directive that declared GPS a dual-use system. He established an Interagency GPS Executive Board responsible for managing GPS as a U.S. asset.
The auto GPS system, or vehicle global positioning system, is an advanced technological marvel. It uses a regional map fed into an electronic guide, usually fitted on the vehicle’s dashboard or undercarriage to help drivers navigate. It provides directions, suggests alternate routes, landmarks, and distances and acts as an anti-theft device by helping owners locate their parked vehicles.
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