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Location, location, location
30 March 2002
From New Scientist Print Edition.

Enlarge Figure 1

It may have begun life as a tool for guiding American missiles and soldiers to their targets, but in recent years the satellite navigation system known as GPS has blossomed into one of the technological wonders of the modern civilian world.

All day, every day, its 30 or so satellites beam radio signals to Earth, and anyone with a receiver can pick them up to get an instant fix on where they are. GPS signals save the lives of mountaineers, keep ships from harm, and let drivers negotiate unfamiliar cities. The service is available to everyone from airlines to taxidrivers. Best of all, the US government provides it free of charge.

Given this, it may seem ungrateful if not downright perverse of the European Union to want to shell out some $3 billion building a rival navigation system called Galileo. But the EU clearly does want to: after years of wrangling over money, its transport ministers this week gave the plans a final seal of approval. And what's more, it's exactly the right move.

Contrary to some suggestions, this is not because Galileo is a technological thoroughbred and GPS an unreliable nag. Yes, Galileo's combination of superior atomic clocks and multiple broadcast frequencies will allow receivers to pinpoint their location to a fraction of a metre. But GPS is already accurate to within 20 metres. By 2005 it will have two further satellites and be accurate to within 5 metres. And using additional triangulation, advanced GPS techniques can pinpoint an object's position to within a centimetre.

The real reason the world needs Galileo is to do with who controls the present system. Unlike Galileo, which will be a civilian service, GPS is owned and run by the Pentagon. The problem with that is that global positioning signals are no longer vital just to American bombers. Aviation authorities are testing GPS for blind landing in fog. Accurate GPS time signals even help to synchronise the world's mobile phone networks and Internet traffic. It's not hard to see how the needs of the burgeoning numbers of civilian and business users of GPS might clash with those of its military owners. If the system were to become faulty, for example, business users would want to know immediately but the Pentagon might not be happy to show and tell. And think of the commercial risks of allowing the present monopoly to continue. Though free now, one day the US might decide to charge for GPS, or it might try to boost sales of, say, American military aircraft by banning GPS military receivers from planes made overseas. To point this out is not anti-American. Would Washington be happy to depend on the goodwill of Brussels for global positioning?

Now that Galileo is go, the US government is lobbying hard to influence the final shape of the technology. Galileo's designers are being warned to keep off the military bandwidth on the grounds that sharing it could degrade the signals through interference. In fact, any interference would be minimal. Each GPS satellite uses a unique code to send its radio signals. This is mainly so all the satellites in the network can use the same frequencies without jamming one another. But the coding also protects the system from interference by other signals.

In truth, the unstated reason why the US wants to keep Galileo off its military bandwidth has nothing to do with interference. The way GPS is designed allows the US to degrade the accuracy of its signals over specific regions should the need arise—think terrorist attacks and armed conflict. At present, Galileo cannot be manipulated this way. It truly will be open to all people all of the time—including terrorists. The US is unhappy about this and is pressing the EU to change the system. If these negotiations fail, placing Galileo's signals outside the GPS military band allows the US to take control itself. In extreme circumstances, it could jam Galileo without disrupting its own signals.

Accepting even the possibility of such intervention would be disastrous for the EU. The key purpose of Galileo is to provide what GPS cannot—a guarantee of a continuous service uninterrupted by military needs. With global positioning such a key part of almost every nation's civilian infrastructure, lives depend on it. There's no point building a civilian alternative to GPS if the Pentagon is then, in effect, handed the keys for turning it off.

If terrorists have a mind to, they will subvert any civilian technology. We can no more use this as a reason to deny global positioning to nations than we can use it deny them road maps, cars and airline tickets.

From issue 2336 of New Scientist magazine, 30 March 2002, page 5

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