The U.S. Department of Defense (DoD) classifies unmanned aerial systems (UAS) into "Groups" according to their size and capability, a joint system that replaced the service branches' separate categorization schemes in 2011.
[4] From about 2004 to 2011,[4][5] U.S. military planners used various "Tier systems" to designate the various elements in an overall plan for integrated operations.
The U.S. Air Force, U.S. Marine Corps, and U.S. Army each have their own tier system.
Role currently filled by the AAI RQ-7 Shadow, although USMC planners do not view this aircraft as meeting future Tier III requirements.
[14] UAS were grouped in four classes under the Future Combat Systems, which was the Army's principal modernization program from 2003 to early 2009: