Although rocket, artillery and mortar (RAM) attacks have not been as lethal in recent conflicts as improvised explosive devices (IEDs) and suicide bombings, they pose an ongoing threat to military installations, forward operating bases, infrastructure and civilian areas. Work underway in the U.S., Europe and Israel is focused on developing effective and economical counter-RAM systems that provide coverage and, importantly, a sense of security to troops and civilians.

Insurgents use RAM attacks as part of asymmetric warfare or as a tactic in terrorism. In many cases the weapons are crude and inaccurate, or outdated. In some instances, they are homemade. Israel, for example, has been the target of more than 10,000 rocket and mortar attacks from Gaza in recent years. While deaths and casualties have been low owing to the inaccuracy of the weapons, their chief objective is to terrorize and demoralize people living in targeted areas. Israel has attacked and destroyed rocket- and mortar-launching teams with aircraft and ground troops, but at a huge cost for each counterattack.

Most experts believe that an effective counter (C-RAM) system is one that provides a layered defense. The best strategy is to prevent an attack. Indeed, patrols and 24/7 surveillance make it difficult for attackers to reach a suitable firing position, especially given the limited range and precision of their weapons, even if some rockets, artillery fire and mortars have greater range.

If this fails, however, there is the active defense option, in which counter-fire is used to break up a sustained attack, and passive defense, which involves assets such as early-warning radar, ground sensors and airborne surveillance, and weapons that destroy incoming threats.

This combination of technology and weapons incorporated into a mobile system is generally the first choice of military planners for an effective C-RAM capability. The concept will eventually be extended to moving targets such as convoys. Lightweight, vehicle-mounted C-RAM systems, similar in operation to mobile air-defense platforms, are expected to become a reality in the near future, providing convoys with a defensive shield against attack, in much the same way that active defense systems guard tanks from rocket-propelled grenades and other weapons.

For the time being, however, the priority is to provide C-RAM for fixed targets.

The first approach taken by the U.S. was to adapt Raytheon’s Phalanx, a close-in weapon system (CIWS) deployed by the U.S. Navy, which features a rapid-fire 20-mm Gatling gun. Similar land-based weapons have been used in the past, notably the M163 self-propelled, 20-mm Vulcan gun deployed for air defense by the U.S. Army; and the trailer-mounted M-167A1/A2, later brought to Pivads (Product Improvement Vulcan Air Defense System) configuration.

The Army rushed development of the Land-based Phalanx Weapon System (LPWS) in 2004 and deployment started the next year in Iraq. Named Centurion by Raytheon, the system is based on a standard Phalanx 1B CIWS, which is mounted on a trailer alongside a power-generation and control system, water-cooling station and ammunition reserve (1,550 rounds). The entire system weighs 24 tons—6.1 tons for the weapon and electronics.

Centurion is a strategically transportable, but not tactically mobile system. It is autonomous, having its own Ku-band acquisition and fire-control radar (known colloquially due to its white dome as R2-D2, the name of the Star Wars movie robot), a Flir thermal imaging sensor and a link to a forward area air-defense command-and-control system. The weapon has an M61A1 gun, which fires 3,000-4,500 rounds per minute. Typically, 400 rounds are fired in each engagement, either in bursts of 60 or 100 rounds, or in a continuous burst. The M940 MPT-SD ammunition, developed for the application, flies faster and thus has more range than the previous M246 HEI-TSD round due to improved aerodynamics. The MPT-SD round flies 1,800 meters (5,900 ft.) in 3 sec., and 2,000 meters in 3.69 sec., and is designed to self-destruct after 3.8 sec.

U.S. and U.K. forces have deployed the LPWS in Iraq and Afghanistan. The system has proven its value in battle, intercepting hundreds of mortar rounds and rockets (insurgents generally do not use tube artillery). To increase its capabilities, the U.S. Army’s C-RAM program office has developed a network concept that links surveillance and counter-fire sensors over large areas that can cover several forward operating bases.

The sensors include the AN/TPQ-36 and AN/TPQ-37 medium- and long-range radars from Northrop Grumman and ThalesRaytheon; SRCTec omni-directional weapon-location radar and AN/TPQ-48 lightweight counter-battery radar from SRC Inc.; and EQ-36 counter-fire target acquisition radar from Lockheed Martin. Northrop Grumman has fielded a similar network in Afghanistan. The networked sensors provide early warning of incoming attack, permitting the LPWS to make an early engagement, which can be done in a fully automatic mode.

The LPWS is only a gap-filler due to its limited range, and is also bulky and heavy. Less range means more systems are needed to cover a given area, with a reduced standoff distance and limited time window to engage a target. The system would be vulnerable to mass artillery attacks.

The Army is consequently investing in follow-on systems. Over the long term, an effective C-RAM system could use laser technology. The U.S. is conducting the Joint High Power Solid State Laser (JHPSSL) project, now in Phase 3, which has C-RAM applications. Several companies, including Raytheon, Boeing, Textron and Northrop Grumman, are working on laser-based C-RAM concepts. Raytheon envisions its Laser Area Defense System as a replacement for the LPWS—the company has tested a laser using the Centurion mount. Northrop Grumman has considerable experience in chemical lasers with the Tactical High Energy Laser (THEL), Mobile-THEL and Skyguard high-energy laser air-defense program. The company is working on a concept called Talon for a mobile, solid-state-laser C-RAM system.

For now, Centurion is the only operational system. While pursuing research on laser systems, the Army is working on a more conventional solution within the Extended Area Protection and Survivability Program (EAPS). This is a missile-based system, for which Lockheed Martin and Northrop Grumman are competing (see p. 15). Flight trials start later this year, and the Army is targeting a Milestone B production decision no sooner than 2015. EAPS is also taking an alternative gun-based approach, with twin 50-mm ATK guns firing “smart” ammunition.

In Europe, C-RAM development takes several approaches. Rheinmetall’s Skyshield/Mantis system, which has been ordered by the German army under the name NBS (Nachstbereichsschutzsystem) and is set for deployment this year in Kunduz, Afghanistan, with a Luftwaffe air-defense squadron, is the first project nearing operational status. Development began in 2007 with a €48-million ($65-million) program funded by the German defense ministry. The weapon, which builds on the Skyshield air-defense system, was extensively tested in Turkey in 2009. The defense ministry awarded Rheinmetall a €110.8-million procurement contract for the first two systems, and a €13.8-million ammunition contract.

The NBS uses Rheinmetall’s 35 X 228-mm Millennium revolver gun, which fires a version of the Advanced High Efficiency and Destruction (Ahead) programmable round. The ammunition dispenses high-density submunitions that can penetrate and destroy thick-walled targets (e.g., 155-mm artillery rounds, 120-mm mortar bombs and heavy rockets). The gun fires high-muzzle-velocity rounds (more than 1,000 meters/sec.) at a rate of 1,000 rounds per minute. A system includes six guns, two unmanned search-and-track units with X-band radar and electro-optic sensors, and a command center. The light weight of each component facilitates transportation—a firing unit with two guns, radar and control center weighs less than 16 tons, while each gun turret is less than 4 tons. The powerful 35 X 228-mm NBS round offers major range and time-to-target benefits over the 20 X 102-mm Centurion round.

Another German company, KMW, is working on a C-RAM concept that exploits the massive 52 X 155-mm artillery gun in a mobile configuration, firing unguided but specialized C-RAM ammunition.

Oto Melara of Italy, a unit of the Finmeccanica group, has two C-RAM projects: Porcupine, a lightweight system using the same 20-mm Gatling gun found on the LPWS, but purpose-built for the mission with a compact and lightweight integrated assembly; and Draco, also known as the Multirole Weapon System, which is based on a mobile version of the popular 76 X 62-mm Super Rapid naval gun and ammunition.

Israel, after a flirtation with laser weapons, has pursued C-RAM defense with a combination of missile-based systems that cover different threats in a layered approach. The lower tier is Rafael’s Iron Dome, with a range of 5-70 km (3-45 mi.). This consists of a multimode IAI/Elta radar, a command-and-control center and three launchers, each with 20 Tamir interceptor missiles. All components are transported on a 6 X 6 truck, ensuring high tactical mobility. Such a battery can protect an area of 100 sq. km (40 sq. mi.).

The first two batteries were delivered to the Israeli air force in July 2010, and a final operational test leading to initial operational capability was scheduled for last December, but postponed for unspecified technical reasons. It should be carried out early this year.

Rafael’s David’s Sling is the next step up in size. It is designed to defend against rockets and cruise missiles, and has a range of 40-300 km. Raytheon and Rafael are jointly developing the Stunner interceptor missile for David’s Sling. The system will not become operational before 2014.

No matter how C-RAM development progresses—whether guns, missiles, lasers or a combination of each proves most effective—only advanced militaries will be able to afford more than a few batteries. The cost of a C-RAM shield, even with economy writ large as a requirement, is immense compared with the cost of artillery, rockets and mortar bombs. One interception of a crude, homemade rocket by a missile-based C-RAM system can cost tens of thousands of dollars—which is one reason why Israel uses radar that computes where incoming RAM will land before intercepting the weapon. If the RAM threat is heading for open land, away from a populated area, a C-RAM system will not be activated.

But as has been evident with counter-IED efforts, militaries will invest billions of dollars to neutralize a threat to personnel and facilities. It is thus expected that work will continue to enhance C-RAM technology despite the cost, until effective and reliable systems are operational.