NAG is an indigenous 3rd generation ANTI-TANK missile which is developed by DRDO.NAG is developed at a cost of 3 billion rs or 44.6million US $. It is a "FIRE & FORGET " system which means once the user locks the target and fires the missile his work is done and he doesn't require to guide the missile towards target after that.It is an all weather system with varying range for various variants.Land base variant NAG has range of upto 4 km but Air launched version HELINA has extended range of 7 kms to 8 kms .
Although NAG is a lock-on before fire missile system but the air launched variant HELINA is also capable of lock-on after launch which means after the missile is launched from the flying platform it can then be locked on target which may not be visible during launch and then it can engage that target .
The missile uses an 8 kg tandem HEAT (High Explosive Anti-Tank) warhead capable of defeating modern armour including ERA (Explosive Reactive Armour) and composite armour.It is capable of engaging both stationary as well as moving tanks and armoured vehicles.The missile uses a top side attack which means when it is fired it attacks the locked target from above (like American javelin system) which is generally the weakest point in tanks because it has minimum armour thickness.
NAG was originally planned to have 3 way guidance systems , it was planned to be wire guided as well as use an active imagine infrared sensor as well as use millimetric wave active radar homing seeker , but the wireguidance system was later removed because army changed requirements and Millimetric Wave Active Radar homing seeker development is underway and its fusion with
active imagine infrared sensor is being worked on to make it capable of firing in all weather conditions .
NAG missile has various variants as per different requirements of ARMY AND AIRFORCE.
- NAG-It is the land based variant which is fired using mounted missile launcher. Namica is a carrier and missile launcher created on BMP2 SARATH platform . It is AMPHIBIOUS LAUNCHER same as the BMP 2 platform it is built on . It can move in water with speed of 7 kms/hr and can carry upto 12 missiles .Land based nag has range of upto 4 kms .
- HELINA- it means HELICOPTER LAUNCHED NAG(HeLiNa). It can be fired from both HAL RUDRA & HAL LCH and has range of 7 to 8 kms .HELINA is also capable of lock-on after launch which means after the missile is launched from the flying platform it can then be locked on target which may not be visible during launch and then it can engage that target .Also the missile is capable of switching targets while inflight.
- Aircraft launched version - an aircraft launched version with range of upto 10 kms is also under development .It will use a nose-mounted millimetric-wave active radar seeker and would be fired from jaguar and hal tejas .
- MAN PORTABLE VARIANT- much like American javelin system .DRDO is working on the,"Man Portable" Nag very . It would weigh less than 14 kg.
The missile till 2010 cleared all Developer trials and army was very happy with the missile so it ordered 450 NAG with 12 HELINA launchers .
Later during final user trials by army the project suffered a setback when missile tested during the summer in Rajasthan failed to achieve its objective of hitting the target at the intended 4 km range. The scientists found the fault with the heat seeker unable to distinguish the heat signature of the target and the surrounding during extreme temperate at great distance. This led to the development of a better seeker with higher resolution and sensitivity that can track and distinguish targets at long distances.
DRDO has also requested to slightly reduce the max range to 3.2 to 3.6 kms for using during day at places like Rajasthan where it is extremely hot during day . This doesn't mean that the range of missile is reduced or anything , the missile is fully capable of engaging the target at 4 kms max distance but during day (mostly between11 am to 3 pm when temp are extremely hot) when the difference in temp of target and surrounding may be negligible(less than even half degree) it may be difficult for seeker to differentiate between target and its surroundings and it may not be able to engage target with pin point accuracy.This problem will be eliminated in next phase or by fusing Millimetric Wave Active Radar homing seeker in missile soon.
The missile with modified seeker was tested again in Rajasthan in Jan 2016 where during night trials the missile score what was said to be "bulls eye " by army.The trial validated the enhanced 4-km range capability of Imaging-Infrared seeker, which guides the missile to the target after its launch.With the modified seeker achieving requisite range capability, the Nag missile is now ready for final, pre-induction user trials.
The army will do the final trials soon and the production of NAG may begin in early 2017 .Currently army has a projected requirements of thousands of anti tank missiles .