Draper to provide interferometric fiber optic gyros (IFOGs) for ballistic nuclear missile guidance

Questions and answers:

• What technology is Draper Laboratory providing for the Navy’s Trident II missiles? Interferometric fiber optic gyros (IFOGs) and related guidance system components that provide precise inertial navigation for the Trident II submarine-launched ballistic missiles.
• Why are IFOGs critical for Trident II guidance? They offer ultra-reliable, self-contained navigation that does not depend on external signals like GPS
• How is Draper supporting the long-term operation of the Trident II missile? Draper is upgrading and replacing inertial measurement units, electronics, and software as part of the D5 Life Extension Program to keep the missile system effective through at least 2042.

WASHINGTON – U.S. Navy strategic missiles experts are asking The Charles Stark Draper Laboratory Inc. in Cambridge, Mass., to build additional interferometric fiber optic gyros (IFOGs) for submarine-launched Trident II (D5) ballistic nuclear missiles under terms of a $68.4 million order announced in August.

Officials of the Navy Strategic Systems Programs in Washington are asking Draper Lab for design analysis, testing, procurement, manufacturing, and repair of interferometric fiber optic gyros. Work is for the U.S. Navy and the United Kingdom Royal Navy.

The IFOG provides inertial guidance and navigation for the Trident II missile. Nuclear missiles must have ultra-reliable self-contained guidance systems that do not rely on outside signals such as satellite navigation systems.

IFOGs have low-mass solid-state configurations that give them advantages like high reliability, long lifetimes, the ability to withstand shock and vibration, a large dynamic range, a wide bandwidth, and low power consumption.

Fiber-optic gyros

Other than munitions, IFOGs also are for automotive, aircraft, and satellites, satellite antenna pointing and tracking, mining and tunneling operations, and helicopter attitude control.

Draper Lab is designing the boost guidance system for the Trident II missile to keep the nuclear weapon system operating through at least 2042. The company is replacing inertial measurement units, electronic assemblies, electronic modules and mission-critical flight and shipboard-test software for the Trident submarine fleet.

These systems upgrades are designed to fit into the space within the missile used by the previous system, and Draper engineers modified radiation-hardened technologies to withstand the rigors of the strategic missile application.

Draper is using a modular design approach that allows simultaneous development of several solutions for higher-risk components, such as gyroscopes. Draper engineers have adapted commercial technologies such as fiber-optics for gyroscopes and magnetoresistive memory.

Nuclear deterrence

Trident II D5s are among the most advanced long-range submarine-launched nuclear missiles in the world. These weapons are the primary U.S. sea-based ballistic nuclear missile, and are deployed aboard U.S. Navy Ohio-class ballistic missile submarines.

The Lockheed Martin Corp. Space Systems segment in Titusville, Fla., builds the Trident II (D5) missile for Navy Ohio-class and future Columbia-class ballistic missile submarines, as well as for United Kingdom Royal Navy's Vanguard-class and future Dreadnought-class ballistic missile submarines.

The U.S. Navy operates 14 Ohio-class ballistic missile submarines, each of which can carry as many as 24 Trident II missiles. Although the Trident II is designed to carry as many as 12 multiple independently targetable reentry vehicle (MIRV) warheads, current treaties reduce this number to four or five.

Each Trident II missile has a range of 4,000 to 7,000 miles, and its guidance subsystem uses a combination of inertial and celestial navigation. The Trident II D5 was first deployed in 1990 and is scheduled to remain in service until at least 2027.

Tell me more about submarine-launched ballistic nuclear missile guidance ...

• Submarine-launched ballistic missiles rely on extremely precise guidance systems to ensure they can deliver their nuclear warheads accurately -- even when launched from a moving, submerged submarine in the middle of the ocean. The missile’s guidance system tracks its position, speed, and trajectory using inertial navigation. The inertial navigation system is the core of submarine-launched ballistic missile guidance. it uses ring laser gyroscopes or fiber-optic gyros – to measure rotation and maintain orientation, while accelerometers measure changes in velocity. Modern submarine-launched ballistic missiles can use star Sightings to correct gyro drift.

The Navy started the D5 Life Extension Program in 2002 to replace obsolete components using as many commercial off-the-shelf (COTS) parts as possible to keep costs down and to enhance the missile's capability. Draper Lab is in charge of upgrading the Trident II's guidance system.

In practice, the Trident II missile's inertial measurement system receives targeting data from computers aboard the submarine. The inertial measurement unit then transmits signals to the D5 flight-control computer and converts them into steering commands to keep the ballistic missile on target.

On this order Draper will do the work in Cambridge and Pittsfield, Mass.; East Aurora, N.Y.; and Clearwater, Fla., and should be finished by February 2029. For more information contact Draper online at www.draper.com, or the Navy Strategic Systems Programs office at www.ssp.navy.mil.