Sea-FDS-IrvinGQ
Radar corner reflectors represent one valuable soft kill countermeasure which can be deployed against radar-guided anti-ship missiles.

Innovations in anti-ship missile design are concentrating the minds of soft kill countermeasures experts to respond in kind.

The naval soft-kill countermeasures engineer has their work cut out: “The evolution of missile technology is making the Anti-Ship Missile (AShM) more challenging to defeat,” asserts Andy Hogben, managing director of Chemring.

His views chime with those of Richard Morgan, business development manager for naval decoy systems at IrvinGQ: “Anti-ship missiles are increasing in threat level by becoming smarter, faster and more sensitive.”

Mr. Hogben cites the use of exotic materials in the construction of AShM airframes as an evolution making these weapons harder to detect. For example, the joint Indo-Russian BrahMos surface-to-surface missile, which could emerge as a potent AShM, is thought to use sophisticated non-metallic composites to reduce the missile’s chances of being detected by a ship’s radars. A warship’s other means of detecting an incoming AShM is by using its electronic support measure to detect radar emissions from the AShM as it activates its radar.

However, increasingly sophisticated radar waveforms employed by AShM radar seekers which use low probability of interception/detection and frequency-agile techniques frustrate the work of the ESM, Mr. Hogben continues: “Early detection and classification is key, as is the ability to employ the most appropriate effector, whether hard or soft kill, or a combination of both, at the right time.”

Similarly, a written statement supplied by Etienne Lacroix to Armada Analysis warned of “future radar seekers which will have higher performance analysers and algorithms to enhance their capabilities.” It added that such advancements could have implications for current soft kill techniques: “Due to technological evolutions, it is now quite easy to integrate a chaff discriminator feature inside the radar seeker, making decoy techniques based solely on chaff less effective.”

Speed is another areas of concern. Emerging AShMs such as the BrahMos can reach hypersonic velocities; that is speeds above 3,333 knots (6,172 kilometres-per-hour) which “reduce ships’ defence response time, requiring more sensitive, earlier warning sensors,” asserts Mr. Morgan. Echoing trends in the anti-tank guided missile domain, these weapons may attack a ship from above to “exploit defensive vulnerabilities.”

Costs

Given the potent nature of the threat, Mr. Hogben asserts that soft kill countermeasures cannot be developed in a vacuum, and must instead be realised in a holistic fashion involving other stakeholders developing warship self-protection systems: “The challenges we face are to gain the threat information of evolving threats, understand how to exploit their weaknesses and then work in conjunction with the end user to develop an appropriate countermeasure.”

This includes a close integration of the ship’s hard kill and soft kill capabilities “to allow a wider choice of responses to enable effective anti-ship missile defence.” Etienne Lacroix agrees, stressing the importance of “being able to quickly fire a decoy before engaging the hard kill capability which enhances survivability for the vessel.”

Arguably not discussed as much as it perhaps should be is the financial cost of vessel AShM defence. Alongside soft kill countermeasures, a warship will be equipped with Surface-to-Air Missiles (SAMs) and Close-In Weapons Systems (CIWS) which can be brought to bear against an AShM threat. However, is it always appropriate to use a SAM or CIWS ammunition, both of which maybe costly and difficult to replenish at sea, when a soft kill countermeasure maybe just as capable of defeating the threat, but at lower cost?

“The challenge we have is then to develop and produce this capability at an affordable cost, i.e. the decoy is a lower cost solution than a SAM, of which the latter cannot be replenished at sea and must be retained for the higher capability threats,” says Mr. Hogben.

“Currently there is almost a one to 100 cost ratio of countermeasures to SAMs. While this will decrease as countermeasures become more complex, they remain highly viable as they can defeat up to 70 percent of the current missile threat and can be replenished at sea to sustain units on operations.”

Mr. Morgan adds that the increasing sophistication of the threat will demand soft kill decoys that can “present a more complex signature through a full 360 degrees.”

One solution is combining soft kill countermeasures when responding to an AShM threat: “This can be achieved through passive decoys working in combinations, with for example, a large spherical floating decoy producing a core bulk radar cross section, complemented when required by other passive RF decoys and infrared flares to create a complex radar decoy image that is quick to deploy and difficult to discriminate from the real target.”

All three companies have a proven track record in developing and producing soft kill countermeasures for navies around the globe, and such countermeasures are very much here to stay: “In the future, passive decoys will remain essential so as to add credible targets in the field of view of the missiles,” says Etienne Lacroix. The continuing proliferation of sophisticated radar-guided AShMs means that they have their work cut out for many years to come.

by Dr. Thomas Withington