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. It has a top attack functionality.
In addition to basic land and helicopter variants the DRDO is now developing number of advanced variants of the Nag missile:
HeliNa, (Helicopter-launched Nag) with a range of 7–8 km, launched from twin-tube stub wing-mounted launchers on board the armed HAL Dhruv and HAL Light Combat Helicopter produced by state-owned Hindustan Aeronautics Ltd (HAL). It will be structurally different from the Nag. The Helina will make use of an IIR seeker for target engagement like the Nag.
The Helina was expected to be tested by the end of 2010. The first ground launches of the missiles were conducted in 2011. During which the missile was launched onto a target and launched. While the missile was in flight, a second target was chosen for the missile to hit which got destroyed. This demonstrated the capability of the missile to lock onto and hit another target while in flight. A 2-way RF command-video data link has been released which is intended to be fired from HAL Rudra.
On July 13, 2015, three round trials of Helina were conducted at Chandhan firing range in Jaisalmer, Rajasthan. As per the defense source the missile was test fired from HAL Rudra and two missiles succeeded in hitting the targets at a range of 7 km, while one reportedly missed the target.