The historic L-70 anti-aircraft gun famed for its use in the second world war is now being optimized as a modern-day ‘drone killer’ by the Indian Army.
The L-70 anti-aircraft gun was one of the most popular medium-weight anti-aircraft systems during World War II and was used by the majority of western Allies. However, the vintage weapon has been modified into a ‘drone killer’ as a part of a project initiated around a year ago by the Indian Army’s Air Defence Corps.
The Anti-Drone Test
On 17th September 2021, the Air Defence Corps carried a successful test of the anti-drone gun. As per reports, a rogue drone was successfully intercepted by the gun. Another test was carried out on 21st September 2021 at the Army Air Defence College on the seafront at Gopalpur, Odisha, where the gun intercepted another 0.6 metres wide commercially purchased drone.
In the first test, a commercially available UAV was shot down from 500 meters away. Initially, the drone was monitored from the command posts of the Air Defence gunners, post which a four-round clip was shot from the L-70 gun fed by special ammunition manufactured by the Bharat Dynamics Limited (BDL). Thousands of tungsten fragments in these 40mm shells were detonated by a proximity fuse, resulting in target neutralization.
The gun is equipped with a counter-drone system developed by Hyderabad-based Zen Technologies Ltd. The private company serves as the Indian Army and Indian Airforce’s (IAF) deterrent against the emerging drone menace.
Counter-drone systems ordered by IAF
The Indian Air Force placed a ₹120 crore order for an unknown number of counter-drone systems in August 2021 from Zen Technologies Limited. The variant of the Zen-Anti Drone Air Defence Systems (ZADS) ordered by the IAF is primarily a ‘soft kill’ system, which means that the system can detect and jam radio frequency emissions from the drone between 10 metres and 10 kilometres.
The first use of it as a ‘hard kill’ system was done during the firing trials in Gopalpur where the system physically destroyed the drone.
An Upcoming New age Threat
Earlier this year, two drones successfully managed to infiltrate and exfiltrate the Jammu airbase dropping two different types of Improvised Explosive Devices (IED) which punched through the roof of a building without any casualties. However, another drone was detected flying near the air force station weeks after the incident.
Pakistan-based terrorists are making use of drone systems to drop arms and ammunition in India, and so, in the wake of such occurrences, the strategic discourse towards anti-drone operations came to higher importance.
As said by former Director-General of Artillery, Lieutenant General PR Shankar (Retd) in a paper published by the United Services Institute of India (USI), “UAV operations are coming of age, and the UAV threat is increasing by the hour. As the threat increases, the need to protect own forces and vulnerabilities against this potent game-changing threat is also growing,”
Low-cost Countermeasure
Because of its small size, the existing ground-based air defence radars are incapable of tracking commercially obtained drones as a one-metre drone has the radar cross-section of a bird and can often be mistaken for one. In-country solutions to replace costly imports are offered by the integration of the counter-drone system along with legacy AD systems.
In an approximated range of ₹6 to ₹8 crores per gun upgrade, older guns like the Swedish L-70s and the Soviet-made ZSU-23 guns can be modified into drone killers. Initially, the guns will have to be upgraded with an electro-optical system before being interfaced with the ZADS counter-drone system; along with that, newer ammunition like the special proximity-fused ammunition shall also be needed for the modified guns.
Approximately 1,180 L-70 anti-aircraft guns are said to be possessed by the Army, which was first bought off-the-shelf in the late 1960s and later licensed and produced by the Ordnance Factory Board (OFB).
However, before being certified for use, the system needs a new X-band radar to detect autonomous drones (those that fly without a link between drone and operator) over the next few months.