Aerial guard: Drones patrolling the border.

• Position: SECURITY BEAT: Homeland Defense Briefs

The Border Patrol will fly a second unmanned aerial vehicle over the Arizona desert beginning this June, according to David Aguilar, the agency's chief.

The decision to deploy an additional aircraft was made after the first Predator B flying south of the Tucson area assisted in nabbing more than 1,000 illegal immigrants and 400 pounds of narcotics in the 2005 fiscal year.

The second aircraft will give the Border Patrol coverage from El Paso, Texas, to the edge of the El Centro sector in California, and will fly 16 hours a day, seven days a week, Aguilar said at a Market Access border technology conference.

Department of Homeland Security Secretary Michael Chertoff has also said in recent months that he wants to employ more space-based intelligence gathering capabilities along the border to prevent the smuggling of humans and contraband.

DHS now must consider an issue with which the military has grappled: space-based versus sub-orbital remote sensing systems.

"We want to go with a system of systems that address our needs," Aguilar said. Satellites could periodically fly over an area such as the remote Sonora Desert and pick up new trails being formed by smugglers, Aguilar said. UAVs, meanwhile, can provide real-time intelligence about border incursions.

Such technologies may not be useful on the northern border where thick forest canopies are found. High-tech listening devices might be better suited for such areas, he added.

David Mosher, senior policy analyst at Rand Corp., told a gathering of military reporters that space is a difficult and costly environment to operate in, and should be used only for unique and hard to replace capabilities.

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