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The submarine community has begun development of a new combat system, the Submarine Advanced Combat System. SUBACS will be the immediate successor to today 1 s AN/BQQ-5 sonar and MK 117 fire control systems. It will eventually encompass the entire combat system including
electronic warfare, exterior communications, and navigation systems.

SUBACS is being designed as a total system from the start, rather than as a family of separately designed, loosely interfaced subsystems as we have built in the past. SUBACS uses distributed microprocessors linked together by digital data buses to provide a degree of reliability and growth capacity not possible with today’s systems. This comprehensive approach will enable SUBACS to support the new sensors and weapons we need to stay abreast of the threat throughout the life of the ships.

As the Navy develops new weapons and improves sensors to counter the improving Soviet submarine
threat and accommodate new attack submarine missions such as strike warfare, the demands for
computer capacity are growing rapidly. Today’ s combat systems, already near the practical limits
of their computer capacity, were not designed for expandability.

Each new weapon, each new sensor, and each new mission also increases the amount of information
the submarine crew must digest in order to fight the battle. This information must be sorted and presented to the submarine commander in a form which supports rapid decision-making in combat.
Today’s information load already taxes the capacity of the crews using today’s methods. For the future, more computer assistance will be needed.

Addition of new capabilities is expensive and cannot continue indefinitely in today’ s systems. Where they require major modifications or wholesale replacement to accommodate growth, SUBACS can grow by adding hardware and software building blocks. When a change is needed, a component can be unplugged and replaced by another, or one added, with minimum disturbance to the rest of the system.

Just as the central computer design limits growth, so does space for new hardware in the 688 Class. This will be solved in SUBACS by the use of new apace-saving microelectronics and dense electronic packaging technology. This approach is expected to recover over 400 square feet of deck space from the present combat system. Through SUBACS, computer reserves will be doubled, with a twenty percent built-in growth potential.

SUBACS will increase combat system effectiveness by improving overall system reliability and availability. Today’s combat systems are somewhat like series electrical circuits — the failure of a single component can put the entire system down. SUBACS, however, is more like a parallel circuit where if one component fails, the remainder continue to operate. Today’s combat systems also contain components which were designed in the mid-60s. SUBACS will capture the latest technology and will be amenable to technology insertion. its circuit cards will accommodate embedment of very high speed integrated circuits which are in the early stages of development.

Reliability can be improved considerably with the more modern design inherent in SUBACS — which
expects to achieve a 99.5 percent availability through redundancy in its distributed processing system. The key benefit from these improvements will be an extremely low probability of failure
during critical phases of combat.

Life-cycle costs for SUBACS will be considerably less than for today’s systems. SUBACS will reduce investment and ownership costs significantly through techniques such as systemwide parts cornmonali ty, modularized software, reductions in the number of types of power supplies and functional modules used, logistics standardization, fewer equipment foundations and
less cabling. for example, the number of unique parts in SUBACS is being reduced by a factor of
three compared to today’s systems; the system contains 28 fewer cabinets, and requires 15,000
feet less cable. The system will also require less operator maintenance and will permit a 40
percent reduction in training costs through rating consolidation.

Costs to upgrade software are expected to drop through the use of a more efficient computer language, modularized software, and the use of Navy standard computers such as the AN/UYK-44 and the Enhanced Modular Signal Processor. SUBACS is also being designed to absorb the next generation of technology without major modifications — a serious deficiency of today’s combat system.

SUBACS will enter the fleet in three stages. Each builds on the previous one in a preplanned
manner leading to the full system in the third stage. This phased introduction gets improvements into the fleet as they are ready without waiting until all are completed. It also spreads the technological risk over time so experience is gained with one improvement before the next is introduced.

SUBACS Basic, the first phase, will emphasize introduction of badly needed acoustic improvements which take advantage of systems now in development. Advanced sonar systems linked by high speed digital data buses will be installed with only minor modifications to the fire control system. This phase of the preplanned product improvement plan sets internal ship arrangements and establishes the overall system architecture so the full system can be backfitted on the first ships at minimum cost. SUBACS A, the second phase, will make major operability improvements, incorporate the fire control function into the integrated system architecture, and introduce the Enhanced Modular Signal Processor.

SUBACS B, the third phase, will add an improved sonar suite. SUBACS B will also introduce the integrated communication system and an expanded electronic warfare support measures suite. SUBACS will use a land-based test site which will be used for configuration management, software
maintenance, and independent verification and validation testing. Each phase of SUBACS will be
tested at sea aboard a dedicated SSN assigned to the submarine development squadron before it
enters the fleet. Ships which received SUBACS Basic and A will get the full SUBACS B backfi t in
their first overhaul.

SUBACS will be installed in all new construction SSNs beginning with SSN 751. It will also be the
combat system for any class of SSNs built as a follow-on to the 688s. It is being designed to
maintain the qualitative combat advantage which U.s. attack submarines presently enjoy and must
preserve if we are to compete with an everimproving foe who outnumbers us.


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