"ATP [Army Techniques Publication] 3-01.8, focuses on how a combined arms force protects themselves from an adversary's air attack. Aerial threats include Unmanned Aircraft Systems (UAS); fixed- and rotary-wing aircraft; rockets, artillery, and mortars (RAM); ballistic missiles (BM) and cruise missiles (CM). Commanders at all levels face the challenge of being able counter the air threat and adversarial reconnaissance within their operational environment. Countering air threats is a shared joint and combined arms responsibility. Dedicated ADA [Air Defense Artillery] forces assigned within a theater are primarily responsible for detection and direct engagements of fixed and rotary wing aircraft, and missile threats to ground forces within an area of operations."
Department of the Army Publications: http://armypubs.army.mil/