Background & Development
The Nag (Cobra) is a third generation, all weather, top-attack, fire-and-forget anti-tank guided missile. It is one of five missile systems developed by the Defence Research & Development Organization (DRDO) under the Integrated Guided Missile Development Program (IGMDP). Design work on the missile started in 1988 and the first tests were carried out in November 1990 .
The missile uses a tandem HEAT (High Explosive Anti Tank) warhead to penetrate ERA (Explosive Reactive Armour) or composite (Chobham type) armour that is found in the latest tanks . The system is expected to supercede Indian production of the Soviet origin 9K113 Konkours (NATO: AT-5 Spandrel) and Euromissile Milan M2 anti-tank missiles .
As originally conceived, the Nag would have been available with three different types of guidance, These included a wire guided version, an infra-red version and a millimetric wave (mmW) version. The cumbersome nature of a wire guidance system had 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 missile has a weight of 42 kg and can engage targets at ranges up to 6 km. The Nag is claimed to be first anti-tank missile which has a complete fiberglass structure .
|A Nag ATGM on display at Def Expo '99 in New Delhi.|
The Nag will be produced in two main versions. The land version has been tested from a tracked vehicle known as NAMICA (Nag Missile Carrier). The carrier is a stretched BMP-2 with an additional pair of road wheels and is manufactured by the Ordnance Factory, Medak. It carries four missiles in a ready-to-fire mode on the turret and more missiles can be reloaded without exposing the crew on the battlefield. 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 is also configured to be used on the Advanced Light Helicopter (ALH). 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 (Nag Missile Carrier) missile tank destroyer - a modified BMP-1 chassis - is fitted with a hydraulically operated elevatable observation/launch platform for the Nag ATGM. This prototype vehicle, unveiled at Def Expo '99 in New Delhi, has already undergone preliminary field trials.
Despite trials since 1990, problems with the guidance system held back successful trials for a long time. The first successful test firing of the missile using an IIR seeker was conducted on 09 September 1997 . Of the two existing types guidance systems, the IIR seeker is now fully developed . The IIR version of the missile has undergone several rounds of successful flight trials since 1997. Flight testing of the helicopter-launched version was carried out from a specially rigged Mi-17 in March 1998 . This was followed by integration with ALH in mid-1999 . The Indian Army accepted the system for user trials in October 1999 . The development of the mmW seeker has been more problematic and it is unlikely that the seeker will enter service any time soon. The missile also employs sensor fusion technology for flight guidance.
During recent test flights, the missile's fire-and-forget capability has been established using the day version of the IIR passive seeker. On 20 January 2000, field tests of the Nag’s Thermal Sight system saw the system identify and lock on to a T-55 tank at a range of 5 km. The tank was then engaged and destroyed at a range of over 4 km . In its IIR form the Nag has limited all weather capability. This has given added impetus to develop the mmW seeker. Efforts are on to provide special embedded on-board hunters, that can hunt for targets using 'day seekers' and 'day-&-night seekers'. A special nitramine based propellant has been developed for the Nag in order to meet its dual requirements of energy and smokelessness .
|A Nag ATGM being test-fired from the NAMICA vehicle.|
Low rate serial production of the Nag began in February 2000. 25 missiles produced by Bharat Dynamics Limited (BDL) in 2000, will all be earmarked for user trials. Full-scale production of up to 200 missiles per year is likely to be launched in early 2001. The Indian Army has a requirement for 500 missiles and the Indian Air Force has a requirement for 100 missiles by 2004 .
 Ministry of Defence. IGMDP Update.
New Delhi: Government of India 1996.
 Jane's Infantry Weapons 1999/2000
Alexandria, VA: JIG 1999.
 Ministry of Defence. Op cit.
 DRDO. ‘Nag Update’. Technology
Focus, January 1998. [print edition]
 Jane’s Armour and Artillery
1999/2000 Alexandria, VA: JIG 1999.
 Own notes. See also ‘Nag test fired’.
Indian Express, 11 September 1997.
 'India's Nag ready for production'.
Jane's Defence Weekly, 06 January 1999.
 Indian Army Press Release, 27 January
 Ibid. See also 'Fire-and-Forget' system
for Nag tested'. Times of India, 22 January 2000.
 Indian Army Press Release, 27 January 2000.
 Indian Defence Yearbook 2000. Natraj Publishers, Dehra Dun, India 2000.
 Indian Army Press Release, 27 January 2000. See also ‘BDL launches serial production of missiles’. Deccan Herald, 09 April 2000.