New surface-to-air missile technology reduces radar signature of Navy fleet

The eponymous Medium Range Surface to Air Missile (MR-SAM), jointly developed by India and Israel to defend the Navy’s warships against incoming anti-ship missiles, achieved a crucial landmark on Friday. MR-SAMs fired simultaneously from different vessels were directed to two different targets by a single warship, allowing a naval flotilla to reduce its give-away electromagnetic signature.

Warships typically switch on their multi-function surveillance and target acquisition radar (MF-STAR) while firing an MR-SAM – usually when an incoming anti-ship missile is still over a hundred kilometres away. The radar guides the missile towards the target, bringing it close enough to allow the missile’s seeker to home onto the anti-ship missile, and strike it precisely while it is still 70 kilometres away.

If a second incoming anti-ship missile is detected, another warship launches a missile to down it. But heavy electronic signatures from multiple radars make the flotilla easily detectable, allowing the enemy to target it with anti-radiation missiles (ARMs).

This vulnerability was reduced through the “cooperative engagement firing” tested on Friday. Two navy destroyers INS Kochi and Chennai fired MR-SAMs simultaneously at two simulated incoming missiles. But then, INS Chennai kept its radar switched off, while INS Kochi directed both missiles to the target through electronic data links.

“The missiles of both ships were controlled by one ship to intercept different aerial targets at extended ranges… The Indian Navy has become a part of a select group of navies that have this niche capability,” stated the defence ministry.

This allows large naval formations – such as an aircraft carrier battle group (CBG), which typically includes a carrier, along with several large warships like destroyers or frigates – to operate with a greatly reduced “electromagnetic signature”.

In a statement of confidence in the MR-SAM, which has been developed by the Defence R&D Organisation (DRDO) in cooperation with Israel Aerospace Industries (IAI) and manufactured by Bharat Dynamics Limited (BDL), the defence ministry announced that the missile system would be fitted “on all future major warships of the Indian Navy.”

So far, the MR-SAM has been operationally deployed only on three destroyers -- INS Kolkata, Chennai and Kochi. Each of them carries 32 missiles deployed in “vertical launch unit” (VLU) canisters. Now they will be fitted on four more destroyers being built under Project 15B and seven frigates being constructed under Project 17A.

IAI has designed and developed about 80 per cent of the MR-SAM, including the Elta MF-STAR radar. The DRDO has designed the missile’s propulsion system, including a sophisticated dual-pulse motor, thrust vector controls, and the electrical harness (wiring).

It was originally planned to deploy the MR-SAM in Indian as well as in Israeli navy warships. While BDL has received orders from the Indian navy, orders from the Israeli navy are still awaited.

The MF-STAR radar is built in Israel, as are the VLU canisters.

The DRDO says the MR-SAM project has enabled the indigenous development of a number of new technologies that will feed into new projects, such as the “quick reaction SAM (QR-SAM). Besides the dual pulse rocket motor, this includes a new smokeless propellant.