Editing Phalanx CIWS (section)

==Operation==
The CIWS is designed to be the last line of defense against anti-ship missiles. Due to its design criteria, its effective range is very short relative to the range of modern ASMs, from {{convert|1|to|5|nmi|km|0}}. The gun mount moves at a very high speed and with great precision. The system takes minimal inputs from the ship, making it capable of functioning despite potential damage to the ship.

The only inputs required for operation are 440{{nbsp}}[[volt|V]] [[alternating current|AC]] [[three-phase electric power]] at 60{{nbsp}}[[hertz|Hz]] and water (for electronics cooling). For full operation, including some nonessential functions, it also has inputs for ship's true compass heading and 115{{nbsp}}V AC for the WinPASS subsystem. WinPASS (Windows-based Parameter Analysis and Storage Subsystem) is a secondary computer built into the local control station that allows technicians to perform various tests on system hardware and software for maintenance and troubleshooting purposes. It also stores data from any engagements the system conducts so that it can later be analyzed.{{Cn|date=April 2024}}

===Radar subsystems===
The CIWS has two antennas that work together to engage targets. The first antenna, for searching, is located inside the radome on the weapon control group (top of the white-painted portion). The search subsystem provides bearing, range, velocity, heading, and altitude information of potential targets to the CIWS computer. This information is analyzed to determine whether the detected object should be engaged by the CIWS system. Once the computer identifies a valid target (see details below), the mount moves to face the target and then hands the target over to the tracking antenna at around {{convert|4.5|nmi|km|0}}. The track antenna is extremely precise, but views a much smaller area. The tracking subsystem observes the target until the computer determines that the probability of a successful hit is maximized and then, depending on the operator conditions, the system either fires automatically at around {{convert|1|nmi|km|0}} or recommends fire to the operator. While firing 75 rounds per second, the system tracks outgoing rounds and 'walks' them onto the target.<ref>{{cite web |title=Last ditch defence – the Phalanx close-in weapon system in focus {{!}} Navy Lookout |url=https://www.navylookout.com/last-ditch-defence-the-phalanx-close-in-weapon-system-in-focus/ |website=www.navylookout.com |archive-url= https://web.archive.org/web/20210619100156/https://www.navylookout.com/last-ditch-defence-the-phalanx-close-in-weapon-system-in-focus/ |archive-date=June 19, 2021 |date=August 10, 2020 |url-status=live}}</ref>

[[File:Phalanx CIWS Tungsten Upload.jpg|thumb|left|U.S. Navy sailors load tungsten ammunition (white sabots at right) and offload [[Dummy round|dummy ammunition]] (left).]]

===Gun and ammunition handling system===
The Block 0 CIWS mounts (hydraulic driven) fired at a rate of 3,000 rounds per minute and held 989 rounds in the magazine drum.<ref name="1987 almanac"/> The Block 1 CIWS mounts (hydraulic) also fired at 3,000 rounds per minute with an extended magazine drum holding 1,550 rounds. The Block 1A and newer (pneumatic driven) CIWS mounts fire at a rate of 4,500 rounds per minute with a 1,550-round magazine. The velocity of the rounds fired is about {{convert|3600|ft/s|m/s}}. The rounds are [[Armor-piercing shot and shell|armor-piercing]] [[tungsten]] penetrator rounds or [[depleted uranium]] with discardable plastic [[Sabot (firearms)|sabot]]s. The Phalanx CIWS 20&nbsp;mm rounds are designed to destroy a missile's airframe and make it non-aerodynamic, thus keeping shrapnel from the exploding projectile to a minimum, effectively keeping secondary damage to a minimum. The ammunition handling system has two conveyor belt systems. The first takes the rounds out of the magazine drum to the gun; the second takes empty shells or unfired rounds to the opposite end of the drum.

The 20&nbsp;mm APDS rounds consist of a {{cvt|15|mm}} penetrator encased in a plastic sabot and a lightweight metal pusher.<ref>{{cite web|url=http://www.military.ir/gallery/albums/userpics/CIWS_article.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.military.ir/gallery/albums/userpics/CIWS_article.pdf |archive-date=2022-10-09 |url-status=live|title=CIWS: The Last Ditch Defense}}</ref> Rounds fired by the Phalanx cost around $30 each and the gun typically fires 100 or more when engaging a target.{{Cn|date=April 2024}}

===CIWS contact target identification===
The CIWS does not recognize [[identification friend or foe]], also known as IFF. The CIWS has only the data it collects in real time from the radars to decide if the target is a threat and to engage it. A contact must meet multiple criteria for the CIWS to consider it a target. {{Citation needed|date=November 2022}} These criteria include:
[[File:CIWS LCP.jpg|thumb|right|A sailor sits at a CIWS Local Control Panel (LCP) during a general quarters drill.]]
# Is the range of the target increasing or decreasing in relation to the ship? The CIWS search radar sees contacts that are out-bound and discards them. The CIWS engages a target only if it is approaching the ship.
# Is the contact capable of maneuvering to hit the ship? If a contact is not heading directly at the ship, the CIWS looks at its heading in relation to the ship and its velocity. It then decides if the contact can still perform a maneuver to hit the ship.
# Is the contact traveling between the minimum and maximum velocities? The CIWS has the ability to engage targets that travel in a wide range of speeds; however, it is not an infinitely wide range. The system has a target maximum-velocity limit. If a target exceeds this velocity, the CIWS does not engage it. It also has a target minimum-velocity limit, and does not engage any contact below that velocity. The operator can adjust the minimum and maximum limits within the limits of the system.

There are many other subsystems that together ensure proper operation, such as environmental control, transmitter, mount movement control, power control and distribution, and so on. It takes six to eight months to train a technician to maintain, operate, and repair the CIWS.{{Cn|date=April 2024}}