The U.S. Defense Advanced Research Projects Agency announced this week it is seeking proposals for its Aerial Dragnet program, a new initiative that seeks to monitor drones flying below 1,000 feet in large cities.

The program seeks to map small drones in urban terrain using innovative technologies that would provide persistent, wide-area surveillance, the agency said in a statement.

While Aerial Dragnet's focus is on protecting military troops in overseas urban settings, the system could also find civilian applications to help protect U.S. metropolitan areas from drone-enabled terrorist threats.

The need for a comprehensive tracking system has increased as off-the-shelf drones become less expensive, easier to fly and more adaptable to terrorist and military needs.

"U.S. forces will increasingly be challenged by the need to quickly detect and identify such craft -- especially in urban areas, where sight lines are limited and many objects may be moving at similar speeds," DARPA said.

The program seeks to replicate commercial websites already existing that display in real time the tracks of relatively high and fast aircraft overlaid on geographical maps.

The Aerial Dragnet program is looking for teams with expertise in sensors, signal processing and networked autonomy.

The agency has posted the program's goals and technical details on FedBizOpps.