Bird's eye view: surveillance drone operators find ways to outsmart enemy.

A burgeoning fleet of unmanned aircraft is among the Army's key weapons against Iraq's insurgency. But the technology alone Is not enough to gain an edge over this enemy, experts say.

While not a tactical panacea, these unmanned platforms are providing an unprecedented degree of situational awareness.

Tactical surveillance drones--particularly those with high endurance and long-range sensors--can be valuable as information-warfare weapons. But to really benefit from the technology, operators must not only be proficient at piloting the aircraft, they also need to be deft at developing tactics on the fly.

In this conflict, UAV pilots are appreciating the importance of being "tactically astute," says Col. John D. Burke, director of Army unmanned aviation.

Soldiers in Iraq operate a range of aircraft--from the 2,000-pound Hunter and the 350-pound Shadow, to the hand-launched 4.5-pound Raven.

Commanders often rely on these aircraft to loiter over areas where they suspect insurgents may be hiding, interacting with the population or seeking to bury explosives along roadsides.

What you want to do is "pattern analysis," Burke says in an interview with defense reporters at the Pentagon.

UAV operators and analysts are like "policemen on the beat," Burke says. Attempting to track insurgents who plant roadside bombs is much like chasing drug dealers, he notes. Ideally, the aerial surveillance can help determine where the bombers come from, what road patterns they drive and where they stockpile explosives.

Having eyes over these areas for extended periods also gives commanders intelligence on insurgent behavior after an explosion or following a U.S. strike, Burke says. "Battle damage assessment is a key mission" for unmanned aircraft.

Imaginative commanders have used Ravens in counterintelligence roles. "They fly it out, and fly it back, to see what I look like to the enemy," Burke says. "Marines have strapped chemical lights on the wings to let the enemy know we are still watching."

But whatever advantages U.S. commanders may gain from flying UAVs over a particular area often are short-lived, because insurgents react to the increased surveillance by changing their tactics. Nevertheless, a relatively large drone such as the Shadow can be seen from the ground and often deters enemy action.

On the other hand, insurgents can gain their own intelligence from these drones. Early in the conflict, Burke relates, when a combat division would end its tour of duty, it would ground the Shadow for about 30 days before a new division took over. "The enemy knew exactly when that division had to take their Shadow off line," he says. "There was a discernible difference in enemy activity when they knew they weren't being watched."

Noise is a major factor in UAV operations. The Raven, which is battery operated, is hard to hear, and small enough that it also may be hard to see. But it's highly susceptible to winds. "Soldiers have to learn tactics such as which way the wind is blowing," Burke says.

Large aircraft with internal combustion engines are quite loud, but still are hard to detect in noisy cities. That requires flying at higher altitudes--about 4,000 to 8,000 feet for the Shadow and 10,000 to 12,000 feet for the Hunter, says Burke. The Raven stays close to the ground, at 100 to 300 feet.

Helicopter pilots in Iraq also have come to rely on these drones to illuminate targets with laser pointers. They can positively identify an enemy combatant, and keep his vehicle illuminated until the helicopter pilot can guide a missile to the target. The laser beam from the UAV is invisible to the naked eye and only can be seen with night-vision goggles, Burke says, adding:

"I've seen missions when they are searching for one truck among many white trucks that all look the same."

To keep up with the rising demand for UAV operators, the Army is accelerating their training. At least 5,000 soldiers have learned to operate unmanned aircraft. Unlike the Air Force, the Army does not require them to be licensed aviators. "Privates are learning to fly Ravens," Burke says.

With hundreds of UAVs in the combat zone, one significant challenge for the Army is integrating the unmanned aircraft into the command structure so they can share their wealth of intelligence with helicopters and ground vehicles, he notes.

The Army's next-generation UAV, called the Warrior, will be built with a "joint common data link" so it can share information throughout the force, Burke explains. The Warrior is envisioned as a brigade-level asset. It will fly at 10,000 to 15,000 feet, and endure up to 35 hours.

The Marine Corps also is in the early stages of design of a new tactical UAV, which would be comparable to the Army's Shadow.

The Marines want the aircraft to fly at relatively high altitudes of 18,000 feet, so it stays out of the reach of ground weapons, says Arslan Safyurtlu, BAE Systems' director of unmanned aircraft systems. The company will propose its Skylynx UAV as a competitor for the Marine Corps program.

The Marine Corps also would prefer that the aircraft not be seen with the naked eye or heard beyond 3,000 feet, he says.

While U.S. military UAVs largely have flown in uncontested air space in Iraq, it could be only a matter of time before insurgents find ways to bring them down.

"A UAV with a large signature loitering at 5,000 feet over a hostile territory is very susceptible," says Robert E. Ball, professor emeritus at the Department of Aeronautics and Astronautics of the Naval Postgraduate School in Monterey, Calif. He notes that the Defense Department's guiding "roadmap" for the UAV industry calls for additional investments in aircraft survivability.

Techniques for making aircraft more survivable to crashes and impervious to enemy surface-to-air weapons range from super-secret signature reduction designs, to advanced sensors to detect incoming weapons, to simpler methods, such as lining the fuel tank with foam.

The Defense Department is expected to spend $17 billion on unmanned aircraft between 2006 and 2011, according to Frost & Sullivan, a market intelligence firm.