How the Army shoots down enemy mortars and rockets
The Army uses a defensive weapon stripped from Navy vessels to shoot down enemy rockets and mortars before they can reach friendly troops. And, as a free bonus, they tell nearby artillery units where the enemy's shot came from, allowing for quick retaliation.
Phalanx weapons were originally fielded as a Close-In Weapon Systems on Navy ships. Raytheon — responding to an Army request for weapons that would shut down mortar and rocket attacks on coalition bases in Iraq — pitched the Phalanx for the new mission.
And the Land-Based Phalanx Weapons System performs. A radar scans the air near protected bases. When it sees an incoming round that could threaten personnel or equipment, the gun and a camera-based tracking system turn to watch it.
At the optimal moment, the Phalanx fires a long stream of self-destructing 20mm rounds from it's six-barrel Gatling gun. The weapon can fire 75 rounds per second.
The armor-piercing rounds disable or destroy the enemy munitions. The rounds self-destruct after a set distance, ensuring that they don't rain down on civilians or friendly forces in the area.
Of course, the system can't always down the incoming round, especially when the system is undergoing maintenance. So most C-RAM equipped bases are equipped with a warning system to alert troops when enemy munitions are incoming.
Either way, the system calculates the most likely point of origin for the enemy round and feeds that information to the fire direction center of nearby artillery units.
When that unit can get eyes on the shooter, they're able to quickly fire counter artillery, destroying the jerks who took the shot in the first place.