Close-In Weapons Systems (CIWS) are effectively the ‘last line of defence’ for naval vessels. CIWS have evolved in recent years as the immediate threats to ships have grown more complex, with new avenues of development in the area for companies and navies alike.
These weapons are perhaps best known for providing protection against Anti-Ship Missiles (AShMs) and are usually based on a gun in the 20mm to 35mm range. However, there is considerable variety among CIWS, both in terms of the systems themselves and the threats they counter, and the line between them and some other gun systems can easily become blurred.
For the US and its NATO (North Atlantic Treaty Organisation) allies, one of the best-known CIWS systems is Raytheon’s Phalanx family. The Phalanx design has been in service since the 1980s, and is based around a 20mm radar-guided Gatling gun; with the latest iteration of the system known as the Phalanx Block-1B Baseline-2. The US Navy is currently upgrading all its Phalanx systems to this new baseline, with the project set for completion at some point in 2019, said Rick McDonnell, director of close-in defence solutions at Raytheon’s missile systems subsidiary. The major change in the latest upgrade has been a series of performance enhancements to the gun’s radar system, he said. This has worked on a number of levels, including upgrades to the radar signal processing architecture, Mr. McDonnell explained, though he could not go into further detail.
The focus for the US Navy over the past decade, aside from major upgrades such as improvements to the radar, has been on boosting the reliability of the system, Mr. McDonnell added, with a variety of subsystems being improved to meet this goal. In addition, there have been changes to the way in which Phalanx systems are upgraded or maintained, he said, with efforts to “improve or enhance the way in which systems are maintained or the way they are repaired,” either at pier side or in a land-based facility. The Phalanx design also forms the basis for other weapon systems, which have come into greater demand as the AShM threat has evolved. For example, Raytheon has also been working on installing its RIM-116 Rolling Airframe Missile family passive radar homing and infrared guided surface-to-air missiles on a range of US ships, said Matt Button, Raytheon’s programme director for the system. The SeaRAM is a version of the Phalanx design in which an eleven-round RIM-116 missile launcher replaces the gun. It has been installed on US Navy ‘Arleigh Burke’ class destroyers, including the USS Donald Cook, USS Porter, USS Carney and USS Ross, where it now operates in tandem with one Phalanx system: “Effectively you’ve added another layer of defence to those ships because they did not previously have the RAM missile,” Mr. Button said: “That gives you a little bit more time to deal with some of these challenging threats.” SeaRAM is also integrated on the Us Navy’s ‘Independence’ class Littoral Combat Ships (LCSs) and will soon be integrated upon the ‘Freedom’ class LCS variant.
Directed energy systems are another emerging area with potential uses in CIWS, perhaps most notably through the US Navy’s AN/SEQ-3 Laser Weapon System (LAWS), which has been tested on the USS Ponce ‘Austin’ class amphibious support ship, using the Phalanx’s radar and fire control systems. Rheinmetall, producer of the 35mm Rheinmetall/Oerlikon Millennium Gun, is also looking into the potential of such technology. Rheinmetall has conducted trials in which the Millennium Gun’s cannon is replaced with lasers, and has worked with the German Navy on developing a High-Energy Laser (HEL) effector. Mr. Wertheim said directed energy systems are the ‘Holy Grail’ of the CIWS domain: “That technology is by far the biggest game changer, because you do not need to be concerned about magazine capacity,” he explained: “When you’re talking about CIWS, very often they have limited magazine capacity, and it’s very expensive to launch defensive missiles. Directed energy alleviates a lot of that.” One of the major advantages of directed energy is the possibility of a theoretically almost unlimited magazine depth, he said. “Right now potential adversaries can build offensive missiles cheaper than we build defensive missiles, so in theory it’s only a matter of time before you get overwhelmed, and you have to leave the battle to re-arm,” Mr. Wertheim noted. “Once you get to directed energy, once you get to something that’s more affordable, then you even the equation out.”