Defensive aids suites are a comparatively recent development created in recognition of the fact that armour cannot guarantee the survivability of a main battle tank let alone the more numerous light and medium fighting vehicles. Military operations in Chechnya, Somalia and in Iraq have shown how easy it is, especially in urban environments, to attack vehicles from the flanks and rear.
Although the weight of tanks such as the American Abrams, the British Challenger 2, the German Leopard 2 and the Israeli Merkava Mk 4 exceeds 60 tonnes it is impossible to provide the same level of all-round protection as is available on the tank's frontal arc. For insurgent groups around the world the rocket propelled grenade (RPG) and the improvised explosive device will remain the weapons of choice for attacking military vehicles. The availability of improved warheads from a variety of sources will possibly make the RPG even more potent.
The US Army stated in its Fiscal Year 2006 budget request, >
Under the Future Combat Systems (FCS) project the US Army is seeking to acquire a new generation of armoured fighting vehicles (AFV) that, with a target weight of 20 tonnes, will weigh less than a third of the latest M1A2, one of the world's best protected tanks. Survivability will be achieved by a combination of technologies, including defensive aid systems (Das), electronic warfare systems, signature management and advanced lightweight armour. This article will examine protection systems in service and under development. Later this year Armada will discuss new armour technology.
Threats to armoured fighting vehicles include:
* shoulder-launched light anti-armour weapons such as the RPG-7 and M72
* first- and second-generation, semiautomatic, command to line-of-sight (Saclos) anti-tank guided weapons such as the AT-3 'Sagger', Milan and Tow
* laser-guided missiles such as the Hell-fire or Copperhead projectile
* kinetic energy (KE) projectiles fired from small and medium calibre guns on infantry fighting vehicles (IFV) and large calibre guns on tanks
* high-velocity long-rod KE projectiles.
The operational concept of a Defensive Aids System--the accurate detection and tracking of a threat and the timely deployment of a countermeasure to defeat the threat--is simple to express but notoriously difficult to achieve. The entire process must be completed within seconds, at a very short range, in all weather conditions and with minimal risk of collateral damage to nearby personnel and vehicles.
Defensive aid systems are divided into two categories: countermeasures or "soft kill' systems and active or 'hard-kill' systems. Soft-kill systems are intended to confuse and divert threat missiles by using signature reduction measures, obscurants, jammers and decoys. An active system engages and destroys or disrupts an incoming missile or projectile before it strikes the target vehicle. It is a close-in system that theoretically creates an active defensive fire zone at a safe distance around the vehicle.
The Soviet Union was the first to deploy a defensive aid suite. This was the Drozd (Thrush) system fitted in the early 1980s on the T-55s of the naval infantry. The system was developed by KBP to defeat Nato missiles such as the Tow, Milan and Hot. The Drozd consists of a pair of millimetric-wave sensors mounted on each side of the turret to detect incoming missiles and a quadruple 107 mm rocket launcher mounted below each sensor. Including the rockets the system weighs almost 1000 kg. When the sensors detect an incoming missile two munitions are launched. A fuse detonates the munition and a cone of fragments is directed into the path of the missile to destroy it at a safe distance from the tank. The Drozd only provides coverage over the frontal arc of the turret leaving the flanks and rear vulnerable to attack, although the system's orientation can be changed by rotating the turret. It was fitted on T-62 and T-80 tanks deployed in Afghanistan during the Soviet occupation and the manufacturer claims the system was 80 per cent successful in defeating RPG attacks. The Drozd was offered on the export market for around $ 30,000. KBP later developed the Drozd-2 system for export with additional millimetric-wave sensors and launch tubes to extend the system's coverage.
The Shtora-1 soft-kill system was first fielded on the Russian T-90 that entered service in 1993. The Shtora-1 has been exhibited at defence exhibitions fitted on Russian T-80U and Ukrainian T-84 tanks as a stand-alone upgrade or part of a package that could also include the Drozd-2. The Shtora-1 consists of four major components: a laser warning system, the electro-optical interface station that includes a jammer, modulator and control panel, a control system consisting of control panel, microprocessor and manual screen-laying panel and banks of forward-firing grenade launchers that are mounted on both sides of the tank turret. The complete system weighs 400 kg.
The Shtora-1 has a 360[degrees] field-of-view horizontally and -5 to +25[degrees] in elevation. When the laser warning system detects a threat laser it alerts the tank commander who then presses a button that automatically turns the turret to face the threat and launch the countermeasures grenades. These form an aerosol screen between 50 and 70 metres in front of the turret in less than three seconds. TShU1-7 electro-optical jammers are intended to jam laser rangefinders, laser target designators and Saclos guided missiles within two seconds of a threat being detected. One jammer each is located on either side of the tank's main gun.
KBM also developed the Arena-E hard-kill system in the early 1990s and this has been exhibited on the T-80 and the BMP-3. The system weighs between 1000 and 1300 kg depending on configuration. A fixed radar mounted on the rear of the turret provides coverage of between 220[degrees] and 290[degrees] with a dead area to the rear. The system's fully automatic operation sees the radar detect a threat approaching the vehicle within the designated speed band at about 50 metres from the vehicle. The system enters target data into the Arena-E's computer, the latter determines which of the 22 to 26 protective charges is best positioned to intercept and launches the round which detonates above the path of the incoming warhead, generating a cone of splinters. Although the incoming warhead is detonated far enough from the vehicle to cause no damage there is a danger zone of up to 30 metres in radius for infantry. According to KBM the time from target detection to destruction is 0.07 seconds (70 milliseconds).