34. Naval Combat Systems

(Published Defence Security India, Feb 2014)

The ultimate aim of a combat weapon system is to destroy the target by transferring energy (through warhead explosion, directed energy etc.) to it, sufficient for its disintegration. A naval combat weapon system comprises of a large number of subsystems interwoven by data links and computers. The system’s capability of multitasking, enables engaging of multiple 3D threats simultaneously. Detection of a target involves search in an area of its presence, localizing the target by finding its range, bearing, elevation or depth and finally its identification. For this purpose, radars, sonars, electro optics, and magnetic sensors are used. Once target is identified, continuous updates are required regarding its velocity and position to enable engagement by the weapon system. Prediction of the target’s future position is essential for launch of a weapon to neutralize the target. The sensors are, in a way, required to follow the target. Track while scan systems enable search radars to carry out the integrated function wherein the sensors input the positional information and the computers calculate and predict the future position. This eliminates the need of separate fire control radar; the fire control solution is available almost concurrently with the target’s detection. Electronic scanning has drastically reduced the reaction times as compared to the mechanical scanning, which had involved physical positioning of the antenna. In the case of underwater targets, sonars are used instead of radars but the medium of water is not as amenable to detection of the target as air and introduces uncertainties, which continue to favor the target. Phased arrays and synthetic aperture technologies are being used in both radars and sonars.

Computers enable a weapon system to detect, track, and predict future position of a target for launch of a suitable weapon. A capable weapon system should also be able to scan for multiple threats and identify potential targets for engagement. Once the weapon is launched, its probability of hitting the target is highly increased if it has been designed for guidance during its flight. Guidance in a weapon implies the ability of the weapon to be guided by external/internal means to the target there by increasing the terminal hit probability. Weapons incorporating guidance include missiles (surface to air, surface-to-surface, and air to surface), torpedoes, and guided bombs. However, the design of a weapon, which is amenable to guidance and fitted with a proximity fuse for detonation of the warhead near the target, is very complex and costly.

A torpedo or missile has some common components like sensor, propulsion, warhead & fuse, electronics (guidance & control, on board computers) etc. Its structure is designed to provide protection to these components against shock and vibration experienced during its launch and propagation to the target. The architecture of the weapon’s structure must support aero/hydro dynamic principals for efficient movement through air/ water. The storage and launch system also form part of the weapon system, the main purpose is to enable efficient replenishment as well as alignment so that the weapon can be placed in line with the estimated position of the target. This is relevant in case of unguided projectiles as well as guided weapons as it enables a weapon to head to the target even if there is a fault in the guidance and weapon has to proceed in autonomous mode. Some of the noteworthy combat systems are described in succeeding paragraphs.

AEGIS Weapon System. This was first deployed on US Naval Ship, USS Ticonderoga. This system covers the complete range from detection of a target to its neutralization. The Aegis radar, AN/SPY-1, has the capability to simultaneously search, track and attack (provide guidance to missiles) up to 100 targets. It is an advanced, automatic detect and track, multi-function phased-array radar. The Aegis has as its foundation  an advanced computer based command and decision system which enables it to carry out operations against multi-mission threats arising from the beneath the sea, surface and air. Lockheed Martin is producing the Aegis weapon system. The US Navy has 72 ships with Aegis system. It has recommenced production of new DDG 51 Class destroyers which will have increased COTS components in its subsystems like the Surface Electronic Warfare Improvement Program (SEWIP), Multi-Mission Signal Processor (MMSP),  AN/SQQ-89(V) Anti-Submarine Warfare/Undersea Warfare Combat System (ASWCS/USWCS), and the Ballistic Missile Defense (BMD) 5.0. It is understood that the BMD capability upgrades are being reintroduced after the development of Dong Feng 21 D carrier killer missile by China. The ships are being provided BMD capability by modifications to Aegis software & computers and provisioning of the BMD interceptor missiles. The BMD missiles are the Standard Missile-3 (SM-3) and the Standard Missile-2 Block IV (SM-2 Block IV). The BMD system has achieved 25 successful exo-atmospheric hits out of 31 trials since 2002. Raytheon currently manufactures the missiles.

Cruise Missiles. Some of the naval cruise missiles worth mentioning are the Brahmos, the Tomahawk, the Klub, and the Exocet. Tomahawk by Raytheon, is perhaps the most famous and widely used cruise missile. It consists of a family of subsonic missiles which can target different types of surface targets. The current version is network centric and can utilize data from a variety of inputs like UAVs, satellites and ground forces. Retargeting during its flight is possible due to its loitering feature. The Russian Klub is an anti shipping subsonic missile with a supersonic terminal speed of 2.9 mach. It has a warhead of 200kg and a range of 220km. Exocet missile produced by MBDA is a sea skimming turbojet missile with a range of +180km. It has a warhead of 165kg. Indian Navy has ordered the submarine fired version of this missile, namely the SM 39, for the Scorpene submarines under acquisition.

The two stage supersonic Brahmos cruise missile is the product of BrahMos joint venture between India and Russia. The Indian Navy had contracted it for fitment on its surface ships after ten consecutive successes in trials. It has been inducted in to the Indian Navy and the Indian Army. Its ramjet ensures cruise speeds of ~three Mach up to its range of 290 km. It carries a conventional warhead of 200-300 kg. Brahmos is capable of being launched from multi platforms like ships, submarines, and aircraft. It is understood that the Brahmos has recently been upgraded by addition of the Russian satellite navigation system, GPS-GLONASS existing in the strategic cruise missiles of the Kh-101 and Kh-555 type. It is likely to be inducted in to the Indian Air force and the Indian Naval submarines once the ongoing trials are completed.

Naval Guns and Close in Weapon Systems. Some of the heavy guns in use are, OTO Melara 127/64, Advanced Gun System (AGS), American 5” Mark 45, OTO Melara 76 mm gun, and Bofors 57/70 mm. The Italian OTO MELARA 127/64 LW Light Weight Naval Gun is used on board the Italian FREMM and the German F125 frigates. This rapid-fire gun can be installed on large and medium size ships, for surface fire and naval gunfire support, with anti-aircraft fire as its secondary role. The compactness of the gun feeding system makes it possible to install it on narrow section crafts. The gun can fire all standard 127mm/5 inches ammunition including the VULCANO long range guided ammunition. VULCANO is a family of Extended Range (ER) unguided ammunition and Long Range (LR) guided ammunition for the 127mm naval guns and 155mm land artillery system. VULCANO is a new and emerging technology based upon a fin stabilized airframe with canard control for terminal guidance; mechanical interfaces are same as standard 127mm ammunition. Various configurations for VULCANO projectiles available for 127mm naval gun are, unguided extended range multirole ammunition, guided long range ammunition with IR seeker and autonomous IMU / GPS guided ammunition.

Also of interest is the 155mm (6-inch) Advanced Gun System, manufactured by BAE Systems, it is intended to fill the gaps in Naval Gun Fire Support role of the US Navy in providing a heavy volume, precise and sustained gun fire support to forces ashore. The LRLAP ammunition is being developed by BAE and Lockheed Martin Missile and Fire Control. The LRLAP is capable of hitting targets at a range of 137 km with rocket booster assisted launch.

A close in weapon system is a last ditch measure to target incoming anti ship missiles/aircraft. Some major CIWS are, Mk 15 Phalanx (USA), Goalkeeper (Netherlands), DARDO (Italy) and the AK- 630 (Russia). The US navy has over 250 of the Raytheon’s Mk 15 Mod 21-28 Phalanx CIWS autonomous combat systems mounted on the US Naval ships. It can be used also against small craft and for ant- air warfare. The Phalanx System is designed as a standalone integrated system which encompasses search (KU band radar and electro-optic), detection, target declaration, tracking, threat elevation, engagement, fire control and damage assessment, this ensures a very quick reaction time that is required for a CIWS. The heart of the Phalanx system is the M61A1 20 mm Gatling gun, providing a rate of fire between 3000-4500 rounds per minute, firing specially designed high kinetic energy rounds. Incidentally the under trial SeaRAM Mk 15 Mod 31 CIWS is also based upon the Block 1B Phalanx with the gun system being replaced by the RIM 116 Rolling Airframe Missile (RAM). It is designed as a companion system to target supersonic ASCMs. It utilises the exact deck dimensions of the Phalanx system and can be conveniently mounted on ships. It has an 11-cell RAM launcher. The RAM is a Mach 2+ missile with a blast fragmentation warhead of 11.2 Kg. It has a range of 9 km. It can be guided in three modes namely; infrared dual mode enabled (radio frequency and infrared homing), infrared only or passive radio frequency/infrared homing.

Indian Naval ships have the following main guns; A-190(E) 100mm,100mm AK-100 naval gun,AK-176-M 76mm gun,AK-76/62 76mm gun, Twin mount gun (76mm), OTO Melara Otobreda 76 mm gun. The CIWS guns include; AK-630 six-barreled 30 mm Gatling gun, AK-230 twin 30 mm gun. Indian Navy also uses Barack 1 point defense missile system from Israel Aerospace Industries (IAI) and Rafael Advanced Defense Systems. The missile is 2.1 m long, with a diameter of 170 mm and has a weight of 98 kg. It has a blast fragmentation warhead of 22 kg weight with a proximity fuse. It has a speed of 2.1 Mach and employs Command to line of sight (CLOS) guidance. Its radar system is known as C3I and it can target missiles as close as 500 meters from the ship. India is also co-developing with Israel a new generation Barack 8 missile with a range of 70 km under a tripartite agreement between DRDO, Indian Navy, and IAI.

Indian Navy has placed an RFP for 127 mm guns in Nov 2013.As far as CIWS (guns) is concerned, a RFI for 30 in number 40mm guns with EOFS has been issued in 2011 and the DAC has in addition cleared a proposal for 116 in number 30 mm guns for the warships in 2012.

Torpedoes. Heavy weight torpedoes are a weapon of choice against ships and submarines. Notable heavy weight torpedoes include the US Mk 48 ADCAP, the Russian 53-65 KE, the Italian Blackshark, and the German Seehect. Hughes Aircraft produce the US MK 48 ADCAP wire guided torpedo. This thermal torpedo has a range of 30Km at 65kts and 50Km at 40kts. It has digital fusing systems, digital guidance-and-control systems, and a sophisticated sonar among other improvements over its previous version. It has reduced self noise due to improvements in its propulsion system. Whitehead Sistemi Subacquei has developed Blackshark also known as A184. It has advanced ECCM, motor design and battery, giving it a speed of +50Km at +50kts. Atlas Elecktronik manufactures Seehecht, DM2A4. It was the first torpedo to be fitted with a fiber optic wire guidance system.

Indian Navy has the SUT-266 German torpedo, the Russian wake homer 53-65 KE, SET 65, and the Russian 71ME wire guided torpedoes. It has been contemplating procuring Blackshark torpedo for its Scorpene class submarines. Indian Navy has recently issued an RFI for heavy weight torpedoes for its submarines and warships in pipeline.

Light weight torpedoes (LWT) are launched form ships and fixed/rotary wing aircraft against submarines. One of the LWTs, which is claimed to be the most tested torpedo in the world is the US Mk 54 torpedo (Raytheon) and deserves a mention as it also traces its lineage from other Raytheon torpedoes like the MK46, Mk50, Mk 48, and ADCAP. It has proved itself against submarine targets in various exhaustive tests in the US. It will replace Mk 46 and MK 50 torpedoes by end of 2014. The Mk 54 torpedo is 271cm to 287cm, weighs between 276 Kg to 293 Kg, and has a diameter of 32 cm. As per Raytheon, Mk 54 Sonar has evolved from Mk 50 and can generate up to 62 independent beams that can be steered in both the horizontal and vertical planes.

The European torpedo of interest is the MU90/IMPACT (A 244/S Mod 3) Advanced Lightweight Torpedo produced by EUROTORP and jointly developed by WHITEHEAD ALENIA Sistemi Subacquei (Italy, a FINMECCANICA company), DCNS International, and THALES (France). As per the manufacturers, The MU90 is a NATO-standard-caliber (323,7mm) fire-and-forget LWT of 304 Kg and 285 cm length, designed to counter any type of nuclear or conventional submarine, acoustically coated, fast-evasive, deploying active or passive anti-torpedo effectors. The torpedo can be deployed from surface vessels, fixed/rotary wing aircraft, or missile.

Indian Navy uses A224S lightweight torpedo manufactured by WASS Italy. DRDO (NSTL Visakhapatnam) has developed Torpedo Advanced Light (TAL) a lightweight torpedo, 2.75 meters in length and weight of 220kg.It is produced and assembled by Bharat Dynamics Limited (BDL). TAL is an anti-submarine torpedo, which can be launched from both, surface ships and helicopters. It can attack and cripple submarines at speeds of up to 33 knots and up to a depth of 540 meters. It uses sea water activated batteries and can travel up to a maximum distance of seven km; it has an explosive weight of 50Kg. The Indian Navy has placed an order for 25 TALs and further orders are likely.

Need for Strategic Perspective. The sheer complexity of the Naval combat system due to, the variety of underlying technologies, the vast number of components covering a multitude of engineering disciplines, the large number of vendors located in different nations, and the high costs,   lead to inevitable collaborations with foreign governments and manufacturers. This in turn raises the question of unhindered supply of components and subassemblies during contingencies in future that may or may not be ideologically favored by the nation where the vendor is located. There is a need therefore of a comprehensive exercise, to correctly identify every source which is required for production and maintenance of a combat weapon system. Thereafter, a study should be carried out about the country’s relation with India, its policies & laws and other factors that may affect weapon component life cycle supplies. In case of slightest apprehension, second sources/alternative designs need to be developed indigenously to eliminate dependencies. In case that appears formidable or involves exorbitant costs then such items need to be sourced in advance as per projected life cycle requirements and local periodic maintenance facilities developed. Since weapon systems have, a life spanning up to three decades there is also a need to have a strategic perspective in to government to government procurements as well as offset clauses. These dependencies can only be insured through effective long duration foreign and domestic policies of the government pertaining to national security of India.