text: Chapter 6
  based Phalanx Weapon System's intercepts require acquisition and tracking of incoming rounds that have
  predicted point of impact within the designated protected area.
  There are three types of defensive operations: area defense, mobile defense, and retrograde. For more
  information on defensive operations, see ADP 3-90. In addition, defense of the homeland by SHORAD
  elements is discussed.
  AREA DEFENSE
  Area defense is a type of defensive operation that concentrates on denying enemy forces access to
  designated terrain for a specific time rather than destroying the enemy outright (ADP 3-90). The focus of an
  area defense is on retaining terrain where the bulk of a defending force positions itself in mutually supporting,
  prepared positions. SHORAD forces in an area defense are generally more focused on protecting designated
  fixed or semi-fixed assets, rather than denying access to terrain.
  In defensive situations, SHORAD commanders support established battle positions based on the IPB,
  METT-TC, and the maneuver commander's scheme of maneuver. These positions need to be planned and
  prepared in depth to provide decisive fires against enemy air attacks. During preparation of the defense, air
  defense priority normally goes to the unit preparing positions and obstacles. Once the defensive positions are
  prepared, priority may shift to C2 and maneuver support assets. When maneuver is required, priority shifts
  to the maneuvering elements. In each situation, SHORAD assets focus on the main air avenues of approach.
  If M-SHORADs or Avengers are tasked to provide coverage for the maneuver force reserves, they should be
  positioned along identified enemy air avenues of approach that influence the reserves' initial positions, as
  well as routes to their defensive positions.
  SHORAD systems will be used in areas that maximize their significant capabilities but minimize their
  exposure to the direct fire fight. M-SHORADs and Avengers are most suited for early engagement of UASs.
  They may initially be positioned with counter-reconnaissance forces or along enemy air avenues of approach
  that allow the enemy surveillance of defensive positions and preparations. For more information on
  countering UASs, see ATP 3-01.81.
  Actual positioning of SHORAD systems should be based on the air IPB, the commander's priorities
  for the air defense, and the location of the supported unit's assets. Avengers, for instance, could be positioned
  as far as 3,000 meters apart; however, the distance between systems is dependent upon line-of-sight and
  METT-TC considerations. M-SHORAD and Avenger systems may be prioritized for engineer effort and
  dug-in to maximize survivability.
  The M-SHORAD guns and the Avenger's machinegun are capable weapons that may be used by their
  crews to defend their position against ground attacks, as well as to engage air targets as required. The
  supported commander may also task the M-SHORAD or Avenger platoon to defend a portion of the asset's
  perimeter. Care must be taken if this task is assigned to ensure that their positions do not now weaken or
  create gaps in the defense against air threats. If they do, the battery commander or platoon leader must so
  advise the supported commander.
  Air defense may be allocated to reserve or counterattack forces, C2 and logistics facilities, and fire
  support units. If the supported unit is defending against an enemy main attack, air defense risks may be taken
  in the rear area to achieve the mass and early engagement needed to defeat the likely attack helicopter threat.
  If defending against a supporting attack, more Avenger and Stinger teams may be allocated to static assets in
  the unit's rear. The ADA plan must be flexible enough, however, to quickly mass against the attack helicopter
  threat should the enemy's main effort shift and occur in the supported unit's sector.
  Since Land-based Phalanx Weapon System units can designate the grid for the point of origin of RAM
  fires sooner than other sources, collocation of Land-based Phalanx Weapon System leaders in a base defense
  operation center or supported unit's operation center is a tactical procedure that helps Land-based Phalanx
  Weapon System units more rapidly synchronize positive identification and clearance of fires. The platoon
  leader can interact with the base commander or supported unit commander for engagement authorization.
  While some units collocate Land-based Phalanx Weapon System leaders with base defense operation centers
  or protection cells, operational experience suggests the best mission command practice is to collocate a sense
  and warn leader in the portion of the supported unit's operation center where intelligence, surveillance, and