text: The Defense
  Limited-Visibility Adjustments
  8-79. The ability of attacking forces to create conditions of limited visibility—including thermal neutralizing
  smoke—and the smoke and dust associated with a battle also means that defending units must be able to
  rapidly modify their defense to one that is effective during limited visibility. Defending units should plan for
  limited visibility rather than full visibility during defensive planning. In this case, defending units may need
  to move closer to the avenues of approach they are guarding. Sensors may still have some value in these
  conditions.
  8-80. Units can expect attacking enemy forces to create or take advantage of limited-visibility conditions.
  Defending units expect attacking forces to take advantage of limited-visibility conditions to—
  * Conduct reconnaissance operations to locate the defending force’s weapons, defensive obstacles,
  and positions.
  * Breach or reduce defensive obstacles.
  * Move elements through gaps in the defending forces coverage caused by reduced weapon ranges.
  8-81. A valid defensive plan includes these items to help overcome potential limited-visibility problems:
  * Long-range detection equipment, such as radar, sensors, and thermal imaging devices, focused on
  well-defined avenues of approach. Employing multiple means in the same area of interest
  improves the likelihood of detection.
  * Deployed weapons systems and some units along avenues of approach that follow terrain features
  potentially used by an enemy force for orientation in darkness, such as wood lines and water
  courses.
  * Increased numbers of infantry, scouts, observation posts, combat patrols, and anti-armor teams
  deployed forward on secondary avenues of approach and between subordinate unit defensive
  positions to detect and slow enemy movement, especially enemy infiltration attempts, and protect
  obstacles against enemy breaching attempts.
  * Emplaced point obstacles and early warning devices along likely night approaches to slow
  advancing enemy forces or to alert defenders to enemy presence.
  * Planned and rehearsed weapons systems and unit displacements and the massing of fires on
  projected enemy approaches. (Defending units moving over previously reconnoitered routes
  should be able to move faster than an enemy force moving through unfamiliar terrain.)
  * Planned illumination on or behind likely engagement areas to silhouette enemy forces while
  leaving defenders in shadows and darkness.
  * Adjustments to the organization of the defense for limited visibility that commence before dark
  and are completely reversed to their daylight configuration before dawn.
  INTELLIGENCE
  8-82. During the planning process, units use intelligence to identify probable enemy objectives and avenues
  of approach. From those probable objectives and avenues of approach, they develop NAIs and TAIs. Units
  study patterns of enemy operations and an enemy force’s vulnerability to counterattack, interdiction,
  electromagnetic warfare, air attacks, and canalization by obstacles. Units also examine an enemy force’s
  capability to conduct air attacks, insert forces behind friendly units, and employ CBRN weapons. Units also
  determine how soon a follow-on enemy force can join an engagement when they are defending against an
  enemy attacking in echelons.
  8-83. Commanders direct their information collection assets to determine the locations, strengths, and
  probable intentions of attacking enemy forces before and throughout their defense. They prioritize early
  identification of the enemy's main effort within their assigned areas. Commanders may need to complement
  information collection operations with combat actions that test enemy intentions. Fighting for information
  can have two benefits: it can make enemy forces reveal their intentions and their preparations.
  8-84. Units use available information collection assets—such as geospatial intelligence, ground surveillance,
  and reconnaissance—to study the terrain. By studying the terrain, they try to determine the principal enemy
  and friendly mounted, dismounted, and air avenues of approach. Units determine the most advantageous area
  for the enemy force’s main attack, as well as other mission variables. Just as in the offense, the echelon