GPS is ready for business use
Tim Landgrave
Published: 18 Mar 2003 13:11 GMT
In the last 10 years, the Global Positioning System (GPS) has gone from a highly sensitive government asset to a tool that businesses can use in many innovative ways. As GPS receivers continue to get smaller and require less power, manufacturers are finding ways to mount them in any device that moves or needs to be tracked -- everything from cell phones to vehicles to heavy construction equipment. When you combine the power of a GPS receiver with the ubiquity of wireless communications, you get an almost unlimited ability to track anything from anywhere. Let's look at the history of the GPS and how it enables businesses to conceive and deploy new tracking applications.
How the GPS was born
In 1973, the Department of Defense (DOD) began investigating the use of satellites to solve its need for a foolproof method of navigation. During a brainstorming session at the Pentagon, several of the DOD's top scientists conceived a system. The final design used 24 Navstar satellites built by Rockwell International that would transmit their precise locations back to ground receivers. Each satellite is the size of a large automobile and weighs 1,900 pounds. The satellites were deployed so that at least four satellites are always in touch with every point on the planet during their 12-hour orbits. By 1993, all 24 satellites had been launched and the system was fully operational.
Although the technology is very complex, the principles behind the GPS are very simple. As it orbits the earth, every satellite continuously broadcasts its position and time within one billionth of a second. From any point on earth, a GPS receiver synchronises with four satellites and triangulates its own position. The position is given in latitude, longitude, and altitude and can easily be translated into a position on a map using simple mapping software.
Why now?
If the GPS system has been operational since 1993, why has it taken so long for businesses to take advantage of it? The GPS is a military device, deployed and maintained by the DOD (at a cost of $12 billion) for military use. Since it transmits signals from digital radios that anyone can intercept, our enemies, smugglers, and terrorists could use the GPS system. Nonetheless, the companies that built the equipment saw an enormous potential market for it. They pressured the Pentagon to make the GPS available for commercial use.
To minimise the potential for abuse, the Pentagon instituted a dual-broadcasting system by which it would transmit encrypted, accurate signals for military use, but transmit less-accurate (to within 100 feet) signals that commercial receivers could process. It also reserved the right to transmit inaccurate signals into the commercial stream on an ad hoc basis to make them less palatable to military or noncommercial users.
In 1996, the White House decided that within 10 years it would provide the military's unencrypted signal to everyone and discontinue the practice of introducing errors into the commercial signal. With this announcement, the government made a commitment to provide GPS services free of charge on a worldwide basis.
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