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by Archives April 5, 2006

The Global Positioning System (GPS) has become a public good, and is relied on by industry and individuals since its inception in 1993. Yet over the years, serious doubts have arisen over having the only fully functional satellite navigation system controlled solely by the world’s foremost superpower. Luckily, Europe may have the answer.

There are a few reasons why a little competition in the global satellite navigation market is a good thing. But first you need to know a little bit of the background.

The GPS uses a constellation of at least 24 active satellites that allows users to determine their location. The satellites send a radio signal with the precise time, as measured by their cesium or rubidium atomic clocks, status messages and the approximate position of every other active GPS satellite. GPS receivers on the ground use the information, and a mathematical procedure called trilateration, to work out longitude, latitude and elevation.

The GPS service is divided into a publicly available signal and an encrypted signal accessible only to the military and a few others. Until as late as 2000, the United States military purposely introduced errors into the publicly available GPS signal. The accuracy of the system was degraded to approximately 50 meters accuracy compared to the system’s actual capability of 5 meters. Supposedly, this was because the U.S. didn’t want other nations or terrorists to use the GPS to guide missile strikes.

The most well-known use of the GPS is as a navigation aid for cars, planes and ships. But it also provides precise timing for scientific instruments and backbone internet servers, accurate missile targeting, nuclear detonation detection, even farming and fishing. If the GPS system were to fail, it would cause quite a disruption.

Now, there is another global satellite navigation system in the works. The Galileo positioning system, named after the Italian astronomer Galileo Galilei, is satellite navigations system being built by the European Union with support from some Middle Eastern and Asian countries. It will use a constellation of 30 satellites and offer better overall accuracy and better coverage of higher latitudes than GPS. The system should be operational by 2010.

Galileo will offer a publicly available signal that will be at least as accurate as GPS and will also offer a signal with accuracy better than one meter, for a fee. Since Galileo will be under civilian control this means that, unlike the GPS, the service won’t be purposely degraded, modified or deactivated during times of war. This also prevents the United States from using the GPS as a political chess piece, threatening to deny service to nations they’re having a disagreement with.

Another reason that Galileo is good news: presumably receivers would be designed to operate with both the GPS and Galileo, so if one system failed, users could always fall back on the other.

Galileo will provide users with a more accurate, more dependable and a non-partisan satellite navigation system and an attractive solution should the unthinkable happen and the GPS fails. Galileo would be proud.

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