PARIS — The U.S. government has alerted the European Union that any preferential treatment the EU gives to its Galileo positioning, navigation and timing network will likely violate World Trade Organization (WTO) agreements signed by the United States and the 28-nation EU.

In particular, U.S. government officials voiced concerns that the EU is weighing equipment mandates for aviation, car-accident reporting and emergency-call regulations that could unfairly tip the scales in favor of Galileo to the detriment of U.S. GPS-enabled hardware.

In a presentation to the 9th Meeting of the International Committee on GNSS, held Nov. 10-14 in Prague, a senior GPS official said the United States and the EU have signed a wide body of satellite navigation agreements designed to promote open market access and interoperability.

These protocols include the WTO’s Agreement on Technical Barriers to Trade, which prohibits discrimination among goods based on nontariff measures including regulations and certification procedures.

Jason Y. Kim, senior adviser at the U.S. National Coordination Office for Positioning, Navigation and Timing, said regulatory measures put into place should be technology-neutral, putting GPS-equipped hardware on an equal footing with Galileo equipment if both meet the regulations’ performance requirements.

The United States and the European Commission, the EU executive arm and Galileo’s owner, in June 2004 agreed to a series of measures to assure interoperability of their systems.

But unlike GPS, Galileo — which is still in development but is expected to launch much of its constellation in 2015-2016 — has always had a commercial ambition.

European Commission officials have said in recent months that they are still weighing how to stimulate Galileo use, especially through regulatory measures requiring that navigation equipment be installed on aircraft, automobiles and other platforms.

“Requiring specific systems arbitrarily prevents or penalizes imports of goods having perfectly functional GNSS capability,” Kim said.

The United States and Russia both have global satellite navigation networks in place. China’s Beidou system, which in addition to positioning, navigation and timing includes a short-messaging capability, is operational in Asia and will be global within two years. Galileo will be globally operational toward the end of the decade.

India and Japan have launched wide-area regional satellite navigation systems.

The United States, the EU and Japan all signed the WTO’s Agreement on Government Procurement, which stipulates nondiscrimination in regulations. China, India and Russia are not yet signatories.

Peter B. de Selding was the Paris bureau chief for SpaceNews.