By BBC News Online's Helen Briggs

Millions of cars, trucks and ships use the network of satellites known as the Global Positioning System (GPS), to pinpoint their exact location on a map and find their way from A to B.

To abandon Galileo at this point would serve notice that Europe is prepared to confer the leadership of major projects to the US

David Baker, Jane's Space Directory

More uses of the technology look set to follow - such as building GPS receivers into mobile phones to allow emergency services to locate a caller in the event of an accident.

However, some analysts say emerging applications are being hampered by concerns that information from the global satellite network, which is run by the United States, could be switched off or restricted in the event of a security threat.

It is these fears that are fuelling calls for the adoption of Galileo, a separate network of satellites that would be controlled by Europe. But at a total projected cost of 3.2 billion euros (�1.9bn), there are doubts in the Union as to whether the independence afforded by Galileo is really worth it.

Back-up system

The German Government recently backed Galileo but other countries, such as the UK, are thought to be ambivalent.

It is claimed Galileo will deliver real-time positioning accuracy down to the metre range

A final decision is expected at the end of March.

Gilles Gantelet is spokesperson for Loyola de Palacio, a European Commission vice-president for transport and energy and a leading proponent of Galileo.

"We consider that it's important to have two systems at least in space," he told the BBC. "It's also good for American citizens to know that if ever there was an attack against their system they could rely on the European one."

Out of control

Not everyone shares this enthusiasm, especially in the United States itself.

What is Galileo?

Europe's own global navigation satellite system Will work alongside US GPS and Russian Glonass systems Promises real-time positioning accuracy down to one metre Guaranteed under all but most extreme circumstances Suitable for safety-critical systems - can run trains, guide cars and land planes

David Baker, editor of the defence publication Jane's Space Directory, says there is concern in Washington that harm or interference to GPS signals could pose a security risk.

And a separate European network of satellites would be beyond the jurisdiction of North America.

"It is felt that there are nations in the world that will acquire weapons that rely on these navigation signals," Mr Baker said.

"Therefore, if there is not an ability to shut that system down if countries are threatened, there will be a vulnerability at a security level."

Jobs at stake

Supporters of Galileo say that it will be safer and more precise than the current GPS system and the Russian Glonass network, which were developed for military use. Approval for Galileo also has important consequences for the European space business.

Giles Chichester, a member of the European Parliament, says that if the project fails to get off the ground, one of the biggest losers will be industry.

"It would be a big set back for European space technology and for those who are employed in supplying equipment and services and software to space observation and other systems," he said.

"It would leave us dependent upon our cousins across the Atlantic who by and large have not let us down up to now."

European prestige

However, according to Ruth Bridger, from the policy unit of the British Automobile Association, the benefits of Galileo to consumers are marginal.

Reasons for Galileo

Gives Europe independence from US and Russia Current services at discretion of military operators Current systems should be backed up for safety reasons Satellite positioning services set to expand Such services demand greater accuracy

"For the private motorist, a lot of the facilities that they can get - traffic information on the move, navigation services on the move, help when they've broken down or had an accident - that is all available now for free," she told the BBC.

"Certainly for the private road user, Galileo will not give a lot more than what they can get at the moment."

The final decision on Galileo is expected on 26 March when European Union transport ministers meet in Brussels. According to David Baker, many countries feel that more is at stake than just technology.

He said: "In many ways, some countries feel that to abandon Galileo at this point would serve notice that Europe is prepared to confer the leadership of major projects to the United States and that that would send a very bad signal."