GPS - military and civilian use in conflict?

Navigation as if by magic

Satellites already provide information for civil and military purposes from space © Astrium / ESA
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The Global Positioning System (GPS), developed and operated by the US military, has become an indispensable part of everyday life. With its help, ships find their way in the mist, scientists survey the earth, farmers monitor their fields and cars know where the next one is Gas station is. Currently, 28 satellites of the GPS system send time and position signals. Receivers need data from at least four satellites to accurately calculate their own position.

Until May 1, 2000, only one signal was available to civilian users, allowing for accuracy in the range of about 100 meters. However, on this date, the disruption factor for civilian users, the so-called Selective Availability (SA) has been completely switched off. Since then, civilian equipment has reached an accuracy of about ten meters, and in good conditions even lower. The GPS also directs the so-called "smart" bombs that drop US and British planes over Iraq. Over a second, the military reserved frequency the accuracies are a few meters and below. GPS still reliable

Canopy of the Ankasa rainforest in Ghana, Africa, taken from a "Fluxtower" measuring station. © Carboafrica

GPS still reliable

With the beginning of the war against Iraq, voices were heard fearing that the US government would re-activate the SA. This could, according to the critical voices, collide airplanes and tankers run aground. Because the US Department of Defense reserves the right to change or shut down the system. "We have seen this both in the Kosovo war and in the first Iraq war of 1991, " says Uwe Carsten Fiebig of the German Aerospace Center (DLR) in a report by the Internet magazine

To counter these fears, the US government issued a statement on March 21 saying that civilian use of the Global Positioning System would not be adversely affected by the war against Iraq, There are plenty of ways to prevent the opponent by regional disruptive factors in the use of the system, it is said.

Asteroid darkens star Stellarium

Financial interests in the foreground

Prof. Kleusberg from the Institute for Navigation in Stuttgart comments: "The US of course did not switch off the congestion factors until they were able to use the technology to regionally prevent the enemy from using the system." Because, as he goes on to explain, "Most users of the GPS system are in the West, and of course you do not want to disadvantage your own users by unnecessarily affecting the system worldwide. " Last but not least financial interests are behind it. The market for technology and applications of the satellite navigation system amounts to several billion euros. At the moment, the US dominates the market. display

But Europe wants to bring its own system into circulation: Galileo will be more precise and, in combination with ground stations, can reach resolutions of less than one meter. It was only in December 2002 that all European partners finally agreed on the financing and coordination of the € 3.3 billion project. The planners hope for up to 100, 000 workplaces. In 2004, the first satellites of the system will be put into orbit. Only four years later, all 30 should be functional. This would solve the conflict between civilian and military use, because Galileo is a civilian-controlled system.

(German Geodetic Commission, 07.04.2003 - Kirsten Achenbach / DFG Research Center Ocean Frontier Bremen (RCOM))