Undersea Technology: The fight for a combat system on the Future Submarine | ADM August 2012

Sometime next year, so Defence Minister Stephen Smith has indicated, government will decide on which combat system, sensors and weapon systems will equip Australia’s Future Submarine.

Although this aspect of the Sea 1000 indicative timetable released on 3 May has received little publicity, these are the decisions that will determine the warfighting capability of the Collins class replacement (although not its range and endurance), and therefore its reason for existence.

Notwithstanding the plethora of design studies and analyses likely to still be underway, they will also point towards which one or more of the four platform options that government is leaning– Military Off The Shelf (MOTS), Modified MOT S, Evolved MOTS (including Collins), or a new design.

These in turn will indicate in general terms whether government is holding to the broad range of capabilities specified for the Future Submarine in the 2009 Defence White Paper or whether it has decided to cut back on these requirements for reasons of design, cost, construction schedule and/or risk.

The combat management system at the core of the combat system, fusing sensor data to create a tactical picture and weapon engagement capability, generally is developed and marketed by a single company. Other subsystems such as sonar, radar, periscopes, electronic support measures, communications and navigation are drawn from a variety of sources.

This can increase the technical challenges involved in integrating client-specified non-standard capabilities, although all the systems likely to be under consideration for Sea 1000 feature open architecture technology, facilitating the interfacing or integration of third party applications.

Intellectual property and/or security issues can also be involved. In the case of the Collins class, US security regulations require the submarines’ Raytheon AN/BYG-1 (V) combat control system to be quarantined, meaning that data from Thales flank and towed sonar arrays must pass through stand-alone processors and a ‘data diode‘ to ensure the one-way movement of information.

Contenders

In addition to the AN/BYG-1 (V), the systems understood to be under consideration for Sea 1000 comprise Lockheed Martin’s SUBICS (Submarine Integrated Combat System); DCNS’ SUBTICS (Submarine Tactical Integrated Combat System); and the Atlas Elektronik ISUS-90 (Integrated Sensor Underwater System).

Of the four, the AN/BYG-1 (V) has been designated the baseline system for the entire US Navy nuclear submarine force and provides the command and control element for Collins, albeit interfaced to a range of separately-supplied sensor and other systems. It is now being marketed internationally by Raytheon as the world’s most advanced submarine combat system tailored to conventional submarine configurations.

SUBTICS equips both nuclear and conventional submarines, ISUS-90 is fitted in several classes of conventionally-powered boats, while SUBICS has been developed for diesel-electric submarines while drawing on Lockheed Martin’s extensive experience with the US nuclear submarine force.

Information on submarine technology is tightly held, none more so than data on combat systems.

Thus the only information Raytheon was prepared to provide on the AN/BYG-1 (V) was a product brochure which nevertheless encapsulates elements which competitors (and potential sovereign adversaries) can be assumed to either match or emulate, or be seeking to do so.

The publication highlights the variety of sonar suites – flank array, cylindrical array, passive ranging, intercept array, towed array, mine and obstacle detection and own noise monitoring – that can be integrated to accommodate unique customer requirements.

Likewise, using Sensor Interface Units and Interface Design Language, national proprietary ESM components or any radar or navigation suite can be integrated into the core combat control system without visibility into national sensitive or classified information. Weapons data senescence and other critical timing requirements are easily fulfilled, Raytheon says, via a high-speed network backbone.

Analogue and digital video obtained from periscopes can be supported through a high-speed local area network without the need for dedicated imaging workstations requiring special hardware configurations. Complex target motion analysis problems are solved with state-of-the-art algorithms jointly developed by the US Navy and Raytheon, the company states.

These are part of a US$1 billion research and development initiative supported by an intuitive, colour-coded parameter evaluation plot which is easily configured to incorporate new algorithms according to customer requirements.

SUBICS

SUBICS is based on Lockheed Martin’s experience as prime contractor and overall integrator for the USN’s Acoustic Rapid Commercial-Off-the-Shelf Insertion (ARCI) program. This has accelerated the introduction of improved signal processing to legacy sonar systems, while maintaining coherence with the parallel development of the command and control, communications and intelligence architecture for Virginia class attack submarines.

SUBICS has been selected as the integrated combat system for Navantia’s S-80 class, which has yet to enter service but is under consideration as a MOTS option for Sea 1000. The system leverages proven commercial technology used on the USN’s Virginia, Seawolf and Los Angeles class submarines, as well as Lockheed Martin’s involvement in ARCI since its inception in 1996.

The open architecture system for the S-80 consists of a Lockheed Martin command and control module and sonar and weapons systems interfaces, with Lockheed Martin having also developed and assembled the cylindrical and 27-metre flank sonar arrays.

SUBICS has also been selected for the upgrade of the Brazilian Navy’s five HDW 2009 Tupi and Tikana-class diesel-electric submarines, enabling the Brazilian boats to use the US Mk 48 Mod 6 torpedo in addition to their existing Tigerfish heavy torpedoes.

However, while SUBICS would provide Mk 48 capability to the S-80, the Spanish Armada has instead selected the Atlas Elektronik Seahake DM2A4 on performance grounds.

SUBTICS is the standard combat system for the DCNS diesel-electric Scorpene, the second of the three Sea 1000 MOTS options.

The system is currently at sea in France’s nuclear-powered ballistic missile and attack submarines, Chilean and Malaysian Scorpenes, the Pakistan Navy’s Agosta 90Bs and Singapore’s two Archer (former Swedish Västergötland) class. It is also in production for the French navy’s next generation Barracuda nuclear attack class, and Indian and Brazilian Scorpenes.

DCNS maintains SUBTICS is suitable for any type of submarine, its design and modular build enabling it to be updated and adapted as required. The system tracks up to 100 targets simultaneously and can control two wire-guided torpedoes (but not the Mk 48) and either two anti-ship missiles or one missile and a free-running torpedo.

ISUS-90

Atlas Elektronik’s ISUS-90 remains the most-widely used combat system for conventional submarines, with more than 80 systems either delivered or under contract to 12 navies.

Equipping as it does the HDW 214, the third MOTS option for Future Submarine, means its performance, along with that of its competitors, is being closely assessed by the Sea 1000 program office.

Yet the system is already well-known to many in the Australian submarine community. Exhaustive testing by the then Defence Acquisition Organisation saw a recommendation in 2001 that ISUS-90 replace the Collins class’s original and cumbersome Rockwell International combat system.

Instead, the government of the day overturned the recommendation and selected the US system based on the core of the AN/BYG-1 (V) 8. This was acquired under an Armaments Cooperation Program agreement enabling joint agreement with the USN rather than just a straight purchase.

Since then ISUS-90 has evolved through several generations, with current developments including vertically expanded flank array sonars and new forward looking active sonars.

Further potential extensions include off-board sensors such as the integration of unmanned underwater vehicles (UUVs) and unmanned aerial vehicles.

The fact that Atlas Elektronik could not rely on funding from a single source to support such developments is seen as a significant plus by the company, obliging it to operate across projects and customers and benefit from a greater variety of operational experiences, perspectives and variations. ATLAS has also provided specialised and tailored solutions serving the needs of individual customers.

As with SUBTICS, ISUS-90 has yet to integrate the Mk 48Mod 7 Common Broadband Advanced Sonar System (CBASS) torpedo, jointly developed by and currently in service only with the US and Australia.

Alfred Schulte, Chief Technical Officer at Atlas Elektronik’s Australian subsidiary Sonartech Atlas, sees no technical reasons why this could not be done – ATLAS Elektronik has integrated a variety of non-ATLAS torpedoes into the ISUS 90 family without any problem in the past.

However, sources close to the Future Submarine program were unenthusiastic about any move to integrate the Mk 48 Mod 7 with a European combat system even if US approval could be gained, citing additional complexity and therefore issues of cost, risk, and schedule.

According to the same sources, a decision to retain the AN/BYG-1 and Mk 48 CBASS combination could not be accommodated within a straightforward MOTS solution.

Combinations

Whether the US combination could replace the fitted systems within a Modified MOTS design, with no change to the hull length or diameter, would be known by First Pass which is scheduled for late 2013/early 2014. Government would also need to be satisfied with an operating concept dramatically different to Collins.

Both AN/BYG-1 and CBASS could be handled by the Evolved MOTS option, with the hull remaining the same diameter but capable of being lengthened as required. Should the preference be for a new design and a combat management system which was not the AN/BYG-1, the likely choice would be the system linked to the nation with which Australia was partnering on the platform design, the sources said.

The platform decision will be made at Second Pass, due in 2017. Given the length of time necessary to field either a new or an evolved design (possibly 18 and 13 years respectively) government could yet produce a surprise – not ‘this one or that one’ but rather ‘this one then