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Unavoidable Fire.

New threats require new countermeasures for land systems

Three men in windbreakers and sweatshirts are behind cover. Two stand in the shadow of a high concrete barrier. One is behind a chest-high wall of sandbags; the other carries an unwieldy launcher on his shoulder, angled up at the sky. There is a burst of translucent smoke, and a cigar-tube shape pops from the launcher. This hangs in the air for an instant before a rocket motor ignites and the shape accelerates and vanishes on a white-hot pinpoint. The thin smoke dissipates quickly, and all three men are watching the horizon for some result. Seconds drag by. Is there some mistake? Then a black-orange explosion blooms in the middle ground. The men flinch involuntarily and somebody yells: " Holy sh [**]!"

The scene changes to a close-up view of a T-72 tank, obligingly motionless. In a frame-by-frame advance, the cigar-tube shape, having sprouted sharp fins, drops down almost vertically on the turret. The frame after contact shows an incongruous tongue of blue flame near the bottom of the tank. In the frames after that, the tank is eclipsed by an expanding fireball. The scene changes again, and the freshly painted T-72 is viewed from the other side in real-time video. Then it is gone in a fiery explosion. Debris flies at the camera, and only a prickly road wheel is identifiable amongst the meager wreckage where the tank just stood.

Meet javelin. This anti-tank guided missile, developed in a collaboration between Raytheon and Lockheed Martin, is representative of a new breed of weapon that defeats the carefully engineered armor of main battle tanks by dropping from above. Javelin has an imaging-infrared seeker and is fire and forget. It is supersonic, has a range in excess of two kilometers, and is man-portable. It is also not the only one of its kind.

Israel's Rafael produces a family of "NT" missiles -- Gill, Spike, and, Dandy -- with imaging-infrared seekers that may also be fired in top-attack mode. The seeker more than anything else is what enables a top-attack profile, achieved by firing the missile at an angle over the target rather then directly at it. The imaging-infrared seeker acquires the target and guides itself down onto it. Other fire-and-forget anti-tank weapons enable this sort of attack profile. The Raytheon/Lockheed Martin Hellfire missile and its cousin, the Alenia Marconi Brimstone, both employ millimeter-wave (MMW) active radar guidance. The Northrop Grumman Brilliant Anti Tank (BAT) munition for the Army Tactical Missile System (ATACMS) uses imaging-infrared and MMW sensors to acquire and seek targets for a top-attack strike, day or night.

The fact is, the anti-tank weapons launched ballistically, semi-ballistically, or from aircraft constitute an increasingly deadly threat to armored vehicles. In his recent "Status on the Development of Integrated Hit Avoidance Systems for the US Army's Ground Combat Vehicles," Ronald Yannone of BAE Systems (Nashua, NH) noted that precision-guided munitions -- including the antitank guided missiles (ATGMs), air-to-surface missiles, and artillery, rocket, and aircraft-delivered high-performance munitions -- are threatening the very viability of battlefield vehicles, even heavily armored ones. Top-attack weapons, in particular, pose the problem of having to add so much armor to a vehicle for protection that the tank would be unable to move under its own power. Yannone predicts that the number of non-US high-performance munitions of all types will grow over the next ten years by more than 500 percent, and the number of ATGMs will almost double over the same time period.

First You Have to See It ...

According to Yannone. armored vehicle survivability is threatened from a number of directions: tank cannon. anti-tank guided missiles, rocket-propelled grenades, smart mortars, and smart munitions. These munitions can be delivered using laser, electro-optical, acoustic, or MMW guidance. Further, the fast reaction time required to counter top-attack munitions makes them an especially dangerous opponent.

Sensor options available to sense the threat spectra include infrared (IR) and electro-optical warners, laser-warning receivers, acoustic sensors, and MMW sensing devices, according to Yannone. Active sensing incorporates MMW radar. The countermeasures include directable IR countermeasures, smoke, decoys, active protection, and others. Acoustic sensors have also been under development for over a decade.

"To protect a tank, it's easier to jam a top-attack missile than a beamrider, especially a ground-skimmer," although neither are particularly easy to defeat, noted Dr. Patrick Mercillon of Aerospatiale Matra Missiles (Paris, France). "You can put an imaging-IR sensor on top of the turret which can relatively easily spot an incoming weapon in ideal 'blue sky' conditions." Once detected and tracked, countermeasures can be launched. Most top-attack missiles, like the Javelin missile, have an imaging-infrared seeker. "So to counter it you blind the homing head," he concluded. Such technology, Mercillon noted, is readily available and relatively simple and just needs to be delivered quickly to a point where it can be used to blind the incoming munition's IR homer. Think of a direct IR countermeasure (DIRCM) for armored vehicles. Such systems are already deployed on helicopters, and could be adapted for use by armored-fighting vehicles.

In "Development Prospects for Air-Launched Antitank Guided Missiles" (Military Parade Publishing, Moscow, Russia), Dr. Arkady Shipunov, Head and General Designer of the Instrument Design Bureau and Professor of Russia's Academy of Sciences, has noted the change in antitank warfare since 1991, including "the emergence on the battlefield of a helicopter with antitank guided missiles, which has caused major upheavals in the general concepts and practices of armed conflict." Helicopter launched ATGMs were first designed to defeat heavily armored targets. However, today's ATGMs are aimed at more agile but less heavily armored targets. and use far more sophisticated guidance channels.

As JED has noted ("Research Continues on the Hit Avoidance ATD." May 2000, p. 32; and "Seeing it Coming," May 2001, p. 53), the emphasis for the beginning of the 21st century is on lighter, more transportable and more tactically mobile ground vehicles. For countermeasures, the main issue is not lust countering the threat, but countering the threat in time. The biggest problem is cueing. Once a tank crew has detected inbound ATGM, it's probably already too late. To be truly effective, the countermeasure needs to be prompted by an on-board warning system built along the same conceptual lines as an aircraft's or ship's integrated defensive suite.

The US Future Combat System (FCS) program seeks to create an entirely new generation of armored combat vehicles to replace the Army's current fleet of General Dynamics Ml tanks, United Defense M2 and M3 Bradley Fighting Vehicles, and other armored vehicles. Vehicle development is scheduled to start in 2006. Realizing that the FCS will be useless without a way to defeat guided munitions, the Defense Advanced Research Projects Agency (DARPA) and the US Army recently awarded initial contracts for the development of new I communications technology for the FCS communications program. FCS operations will require a new level of high-speed, stealthy communications to support real-time fire control and robotic missions in hostile electromagnetic environments. DARPA plans to use a multitiered, mobile, ad hoc network with directional antennas at low frequencies (e.g., frequencies used by the joint Tactical Radio System) and highly directional antennas at high frequencies (above microwave bands).

Laser-warning systems can also help a tank crew know they are being targeted, although as one JED source put it, this may only serve to aggravate the situation "by letting the tank crew die all tensed up."

Compact laser warners do exist for infantry and may be used by a tank crew when conditions permit. The Ultra-Compact Laser Threat Warner from the Indian Ministry of Defense's (IMD's) Laser Science & Technology Centre is a hand-held warner that, when lased, gives both an audio beep and a visual indication. The IMD claims that it is also capable of distinguishing between low pulse-repetion-frequency (PRF) (such as those from tank range finders) and high PRF (such as those from laser designators) laser threats. It is a totally indigenous effort by India, both in design and implementation. The warner has been tested extensively in the laboratory for a simulated range up to 3 km and in the outdoor conditions within the laboratory ranges.

The IMD claims that it is capable of detecting, within a wide 60-degree-plus field of view, visible or near-IR laser threats from existing and emerging battlefield pulsed solid-state lasers, such as laser range finders, laser designators and of solid-state laser countermeasures (laser dazzlers, anti-sensor lasers, etc). Further, the warner with slight modification, can be adapted to multiple sensor configurations, which gives it a broad direction-sensing capability in the form of pre-defined sectors. One such application could be a turret-mounted multiple sensor system in which four laser sensors spaced 90 degrees apart would provide 360-degree battlefield coverage.

From Avitronics (Centurion, South Africa) comes another warner for defense against laser-guided missiles: the LWS-CV. According to Avitronics' Cobus van der Merwe, Land Systems Program Manager, LWS-CV operates in the 0.5-1.8 [micro]m and is effective against known range-finders, beam-riders, designators, and dazzlers and has a unique anti-reflection capability that eliminates reflection from surrounding objects as close as 2 m away from the vehicle. It also contains an integral, pre-programmed but user-definable threat library. Avitronics believes this is unique among ground-vehicle laser-warning systems. The LWS-CV also uses integral algorithms for fast threat identification, which is so far unique in the land environment. It is currently under evaluation by several European countries and is currently being installed by the South African Army on some of its vehicles.

... Then You Have To Block It

According to another JED source, a former US Army aviator, "Frankly, the best defense against top-attack weapons is for the tank crew to put the son of a bitch in reverse and race back down their hole." Noting that a crew has to back-up pretty fast to dodge a Mach 3 missile, he also mentioned that armored vehicles do have stores dispensers to launch smoke and flares to confuse incoming rounds, but that it's a tough defense to mount.

Camouflage netting may also provide some protection, he noted, in reducing a target's signature. The incoming munition -- especially a top-attack weapon -- looks for a specific signature return for a tank or other particular target. Camouflage that changes the return signal confuses the incoming round and can reduce the likelihood of being hit as much as 75-80 percent, according to one source. Such camouflage can be in the eloctro-optic/IR spectrum or in the RF spectrum. For RF confusion, some camouflage presents a surface with the texture of a pile of corn flakes, greatly deflecting the RF signal. The Mobile Camouflage System from Saab Barracuda (Gamleby, Sweden), for example, offers protection from seekers operating in visual through RF wavelengths.

Vehicle-defense systems under development include the Commander's Decision Aid (CDA), a sensor-fusion system under development by the Hit Avoidance Team (HAT) of the US Army's Combat Vehicle Survivability Group at the Tank-Automotive Research, Development & Engineering Center (TARDEC) (Detroit, MI). The CDA seeks to declare threats and suggest countermeasures. Another TARDEC project -- the Active Protection System (APS) -- seeks to defeat

incoming rounds by use of bullet-on-bullet technology involving very-high- velocity rounds and very short timelines in which to react, with virtually no room for error. While no specific defensive ordnance systems have yet been identified, warheads tested for the APS include solid-fuel air explosives, explosively formed penetrators, buckshot-like fragmentation munitions, nets (effective against parachute-borne antitank munitions), and airbags (which would actually be mounted on the vehicle's outer surfaces).

Other planning has included work on another specialized APS, dubbed the Small, Low-Cost Intercept Device (SLID), a DARPA program managed by the Army's Picatinny Arsenal, NJ. The SLID program has been developing and testing a system that protects threatened vehicles against missiles and projectiles by detecting, tracking, and intercepting with explosive warheads at a standoff distance. While an interceptor system and fire-control system were successfully tested in 1999, future funding has not yet been announced.

At the moment, the Russians have one of the few working and perhaps the best missile-countermeasure systems for tanks: Schtora, which defends against ground-skimming, laser-guided missiles by using a laser and smoke to blind the incoming round. It is possible that the technology could be applied to top-attack threats as well. Thales (Paris, France) has made some tentative moves with Russia in possibly exporting Schtora to other countries.

Oerlikon Contraves Defence (Zurich, Switzerland) produces Skyshield 35 AHEAD, an ATGM-defense system claimed to be effective in defeating top-attack and beam-rider munitions. It features twin, remotely controlled, radar-directed 35mm gatling guns, each firing up to 1,000 rounds per minute. The system claims a 4.5-second reaction time between detection and firing, great accuracy, and multi-target engagement of subsonic and supersonic attack weapons; ranging from precision-guided ATGMs, tactical aircraft, attack helicopters, cruise missiles, and unmanned combat aerial vehicles. Skyshield 35 is designed to work in conjunction with Oerlikon's ADATS missile system when engaging targets up to 10 km away. When used together, both are directed by a single fire-control unit. The main drawback is that Skyshield is a towed system and is unsuitable for protecting armored formations on the move.

Perhaps the final word comes from Avitronics' van der Merwe. "We are now starting to apply detection and protection techniques to land vehicles that had until now been used only with aircraft." Considering the new "death from above" threats to armored vehicles, whose ancestors clunked across barbed wire and dirt trenches not that long ago, this seems only fair.
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Title Annotation:defending against top-attack missiles
Author:Sherman, Kenneth B.
Publication:Journal of Electronic Defense
Geographic Code:1USA
Date:Oct 1, 2001
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