Northrop Grumman Corp. beat out Boeing Co. and Lockheed Martin Corp. to win a $1.16 billion Navy contract to design and develop an unmanned aircraft for patrolling coastlines and the open ocean.

Although the Broad Area Maritime Surveillance — or BAMS — award announced Tuesday is for the initial development of the plane, the contract could ultimately be worth several billion as the Navy buys as many as 44 unmanned aircraft. The president’s 2008 budget request includes $2.3 billion for research, development, test and evaluation for the program plus another $780 million for procurement.

The Australian government, which has invested in the BAMS development program through a $15 million agreement with the U.S. Navy, is also expected to become a major customer for the new planes.

Los Angeles-based Northrop Grumman won the competition with a version of its Global Hawk surveillance aircraft, which is primarily used by the Air Force. Boeing had partnered with General Dynamics Corp., maker of the Gulfstream corporate jet, to offer an unmanned version of the Gulfstream G550. Lockheed partnered with General Atomics, maker of the Predator unmanned aerial vehicle, to offer the Mariner, a version of the Predator with longer wings, more fuel and more capacity.

Through the BAM initiative, the Navy is seeking long-endurance planes that will be able to fly in a radius of 2,000 nautical miles and will provide port surveillance, battle damage assessments and reconnaissance of everything from surface vessels to submarine periscopes. The program will work with the Navy’s P-8A Poseidon, a manned maritime surveillance aircraft built by Boeing, to replace the Navy’s aging P-3 Orion maritime patrol aircraft.