The U.S. Navy has upgraded the radar and heat sensors on its Phalanx CIWS (Close In Weapons System) so that that the sensors can detect speedboats, small aircraft and naval mines. The upgrades will cost $4.7 million per system. Of the 57 systems being upgraded to this Block B standard, 17 of them are the land based, Centurion, version of Phalanx.
Centurion is basically the Phalanx naval gun system with new software that enables it to take data from other radar systems, and shoot down just about any kind of artillery shell or rocket within range. Centurion uses high explosive 20mm shells, that detonate near the target, spraying it with fragments. By the time these fragments reach the ground, they are generally too small to injure anyone. At least that's been the experience in Iraq. The original Phalanx used 20mm depleted uranium shells, to slice through incoming missiles. Phalanx fires shells at the rate of 75 per second. Another advantage of Centurion, is that it makes a distinctive noise when firing, warning people nearby that a mortar or rocket attack is underway, giving people an opportunity to duck inside if they are out and about.
The first Centurion was sent to Iraq in late 2006, to protect the Green Zone (the large area in Baghdad turned into an American base). It was found that C-RAM could knock down 70-80 percent of the rockets and mortar shells fired within range of its cannon. Since then, the U.S. Army has received 22 Centurion systems (and Britain got ten). The U.S. Centurions defeated 110 rocket and mortar attacks against American bases. Not bad, since it only took about a year to develop Centurion. Each one costs $15 million.