President Bush travels to Ireland on Saturday to discuss such issues as Iraq, the Middle East and trans-Atlantic economic ties with top officials of the European Union. The EU-U.S. summit will have a full agenda, but will only last about three hours and the main agreement is expected to be a highly technical one.

Ireland, which holds the EU's rotating presidency, is hosting Mr. Bush and some of his top aides at a remote castle in the western part of the country. Mr. Bush's visit is expected to draw thousands of protesters who oppose the U.S.-led occupation of Iraq and Irish authorities will deploy more that 6000 police and soldiers to ensure security.

Irish Prime Minister Bertie Ahern wants to avoid any controversy, even though the Bush administration and the EU still have differences of opinion on several agenda items.

Take Iraq, for example. Diplomats in Brussels say they expect Washington to ask the Europeans to do more there in helping to stabilize the country. But the EU insists it has no intention of going beyond providing humanitarian assistance to Iraq and helping the interim Iraqi government prepare for elections next year.

Then there is the question of Washington's plan to encourage political and social reforms in the Middle East. EU diplomats say the administration has had to scale back the plan because of opposition to it in the Arab world. They also say the U.S. plan has little chance of succeeding unless Washington adopts a more even-handed approach to the Israeli-Palestinian conflict, a move they consider crucial to restoring U.S. credibility in the region.

The diplomats say there will be a statement at the summit on the humanitarian crisis in the Sudanese region of Darfur and discussions on counter-terrorism and non-proliferation, and a commitment to reduce HIV/AIDS.

But Irish Prime Minister Ahern is highlighting the economic ties between the two sides of the Atlantic. Writing Wednesday in The Irish Times newspaper, he says trans-Atlantic trade is worth $2.5 trillion, and directly or indirectly employs 12 million people.

The one concrete success of the summit is likely to be the signing of an agreement that makes the EU's planned $4 billion satellite navigation system, known as Galileo, compatible with the existing U.S. Global Positioning System (GPS).

The Pentagon, which controls GPS, initially criticized Galileo as unnecessary and a potential security threat during wartime, saying its signals could interfere with GPS signals intended for use by the military.

But EU Transportation Commissioner Loyola de Palacio told reporters those differences have now been overcome and that GPS and Galileo together will become the world standard.

She said that all users will, with a single receiver, be able to use either system or both simultaneously.

As part of the deal, the United States will upgrade GPS with a stronger military-only signal that will be less vulnerable to enemy interference than the weaker civilian signal currently in use.

But another hoped-for agreement on a trans-Atlantic commercial aviation will not be struck in time for the summit. U.S. and EU negotiators have been working on a deal that would pave the way for trans-Atlantic aviation mergers and more vigorous competition but have failed to narrow their differences.

The United States has agreed to let EU investors own up to 49 percent of a U.S. airline but refuses so far to allow European carriers access to the U.S. domestic market. EU transportation ministers last week told Washington to improve its offer or forget about a deal.