Nag (missile) - Technical Characteristics

Technical Characteristics

As originally conceived, the Nag would have been available with three different types of guidance, a wire guided version, an infra-red version and a millimetric wave (mmW) version. DRDO failed to develop a wire guidance system had this led to plans for this being dropped. Currently, guidance is based on an imaging infra-red (IIR) passive seeker that ensures a high-hit accuracy in both top- and front-attack modes.

The mmW seeker, on the other hand, is intended to operate as an optional system that can replace the IIR passive seeker as a module. Also incorporated into the guidance system, is a CCD camera. The advantage of this optical seeker is that it is less prone to jamming. The missile has a weight of 42 kg and can engage targets at ranges 4–5 km. The Nag is claimed to be first anti-tank missile which has a complete fiberglass structure.

Another advantage of the missile is property of the propellant. Most missiles leave a plume as the missile heads toward the target. This makes it harder for the firer to remain hidden. In the Nag, however, the plume is visible only during the first one second of flight, as the missile's booster imparts 90% of the velocity, following which, a sustainer maintains the missile's speed, burning a smokeless propellant that is almost invisible.

The Nag has a flight speed of 230 metres per second, is armed with a 8 kg tandem shaped-charge warhead, has a rocket motor using nitramine-based smokeless extruded double base sustainer propellant, has a single-shot hit probability of 0.77 and a CEP of 0.9 metres, and has a 10-year maintenance-free shelf-life. Recently, it was tested from Shamirpet in Hyderabad on 13 June 2010.

The Nag will be produced in two main basic variants. The land version has been tested from a tracked vehicle known as NAMICA (Nag Missile Carrier). With the IR version of the missile, targets are acquired using a thermal sight, and are then assigned to the nose-mounted IIR seeker.

Missile guidance is initially by area correlation around the target, then by centroid tracking. Terminal homing is by area correlation around the centroid.

Nag will be configured to be used on the Advanced Light Helicopter(ALH) and the HAL Light Combat Helicopter(LCH). This version will be known as HELINA (HELIcopter NAg). Eight missiles are carried in two quadruple launchers. Launchers mounted on either side are linked to a nose-mounted stabilized thermal sight and a laser range-finder package.

The NAMICA version of the missile is a 'lock-on before launch' system, where the target is identified and designated before the missile is launched. As the targeting system is based on visual identification, the range is limited. The HELINA version on the other hand will use a 'lock-on after launch' system extending its range to 7 km. In this scenario, the missile is launched in the general direction of the target. As it approaches the target, images of the area ahead are sent back to the operator who will be able to identify enemy tanks. The command to lock on to a tank is then passed onto the seeker through an uplink mid-flight. After that, the missile homes in onto the target and destroys it.

The word Nag means Cobra in Sanskrit. The missile was named thus because of its trajectory. It doesn't follow a completely parabolic path like conventional projectiles but hits the target as a snake hits its enemies. The missile moves near the target in a parabolic path, suddenly rises upwards and then bends at a steep angle and hits the target.