Global Positioning Systems (GPS)
Another interesting development in ITS is GPS. The design of GPS goes back to the early 1940’s, based partly on the similar ground-based radio navigation systems, such as LORAN LOng RAnge Navigation) and the Decca Navigator, both 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 satellite in 1957. A team of U.S. scientists led by Dr. Richard B. Kershner were monitoring Sputnik's 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. The scientists 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.
The first satellite navigation system called Transit, used by the U.S. 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 U.S. Navy developed the
Timation satellite which provided the ability to place accurate clocks in space, a
technology the GPS relies upon. In the 1970s, the ground-based Omega Navigation System,
based on ‘signal phase comparison’, became the first world-wide radio navigation system.
On-board vehicle navigation systems:
Navigation systems pinpoint a vehicle's location, using military-installed global positioning system satellites across the country. When combined with mapping software, the maps displayed on a screen in the vehicle provides a show-and-tell to drivers on the closest route or quickest way to reach a predetermined destination.
When a driver makes a wrong turn, the system gently guides them back on track. Some Navigation systems contain special features such as points of interest, restaurants, gas stations and hospitals.
Emergency vehicle notification systems
Another ITS development is the Emergency vehicle notification system. In the U.S.,
a leader in innovative vehicle safety security and information devices is GM’s OnStar
system. The system is described below, taken from the GM’s OnStar website.
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