Small Smart Bomb

[David]

Small Smart Bomb
Miniature Munition Capability
Miniaturized Munitions Technology Demonstration (MMTD)
Swing Wing Adapter Kit (SWAK)


As of 07 January 1998 ACC approved a new acquisition strategy for the Small Bomb System (SBS) program. This strategy involves integrating the SBS on the F-22, F-22X and JSF and also includes combining the SBS and the Low Cost Autonomous Attack System (LOCAAS) efforts into a single program. This new program has been designated Miniature Munition Capability and has a planned start date for FY03. Implementation details of the new strategy are still being developed.
The Small Smart Bomb is a 250 pound weapon that has the same penetration capabilities as a 2000lb BLU-109, but with only 50 pounds of explosive. With the INS/GPS guidance in conjunction with differential GPS (using all 12 channel receivers, instead of only 5) corrections provided by GPS SPO Accuracy Improvement Initiative (AII) and improved Target Location Error (TLE), it can achieve a 5-8m CEP. The submunition, with a smart fuze, has been extensively tested against multi-layered targets by Wright Laboratory under the Hard Target Ordnance Program and Miniature Munitions Technology Program. The length to diameter ratio and nose shape are designed to optimize penetration for a 50lb charge. This weapon is also a potential payload for standoff carrier vehicles such as Tomahawk, JSOW, JASSM, Conventional ICBM, etc.

The goal of the predecessor Miniaturized Munitions Technology Demonstration (MMTD) effort was to produce a 250-pound class munition effective against a majority of hardened targets previously vulnerable only to 2,000-pound class munitions. Using personnel and experience gained from the GBU-28 "Bunker Buster" program and the Exploitation of Differential Global Positioning System for Guidance Enhancement (EDGE) programs, the MMTD test team completed development testing in 18 months. McDonnell Douglas was awarded a $6 million contract to assist in the design and development of the MMTD concept. After completing successful warhead (Jan 96) and system (Mar 96) CDRs, the warhead already demonstrated the objective of penetrating 6 feet of reinforced concrete.

The second phase which integrates terminal seeker and anti-jam GPS technology into the Phase I baseline weapon is planned for FY99-02 under the Miniature Munition Capability effort. Because of the short flight times (about one minute) the GPS receiver must have fast acquisition capability.
The guidance law will be designed to penetrate the target with an obliquity angle of zero degrees. There is however an obliquity angle tolerance of approximately 20 degrees; anything greater will not ensure case survivability. The angle of attack at impact is constrained to be zero degrees with a tolerance of one degree. This nulling of the angle of attack must be achieved at least one missile time constant prior to impact. In addition, the munition is required to penetrate with an impact velocity of at least 1100 ft/sec. Consequently, the guidance law will be designed to optimize terminal velocity subject to the aforementioned constraints. In order to maximize terminal velocity, the vehicle will fly in a coordinated bank-to-turn mode (as opposed to skid-to-turn). While this does increase the complexity of the flight control system, the advantage of increased speed and maneuverability outweigh the increased complexity. The control variables for the guidance law are angle of attack (or normal acceleration) and bank angle. The autopilot architecture will be designed to be robust to disturbances and plant uncertainties. In addition, the autopilot is required to track the angle of attack and bank angle commands from the guidance law while stabilizing the vehicle. This will require a robust autopilot methodology. Many modern design techniques, such as LQR/LQG, LQG/LTR, Mu-synthesis, can provide controllers which achieve the specified design requirements. Implicit in this is the need to gain schedule the designs with altitude, Mach Number, angle of attack or a combination thereof. Analysis of the stability and performance robustness will be performed to ensure meeting the guidance, navigation and control requirements.
Flight testing demonstration for multiple Small Smart Bomb ejection external carriage from an F-16 is scheduled for 3Q00, and an internal carriage combined test event with the Royal Australian Air Force in 1Q01.


The Swing Wing Adapter Kit (SWAK) is added to give the SSB standoff of greater than 25 nm from high altitude release. The wing kit is jettisoned at a midcourse way point if penetration is required so that velocity can be increased after wing release. For soft targets the wing kit continues to extend the glide range until small arms threat altitude is reached. At this point the wings are released. With INS/GPS guidance, coupled with AII, a 6-8 m CEP can be achieved. This wing kit allows the SSB to be directly attached to the aircraft at any 300 lb store station or packaged in the High Leverage Munitions (HLM) for higher density carriage.

The second generation SSB has an advanced warhead which is designed to maximize penetration capability without sacrificing blast/fragmentation potential. This is achieved by use of liners to control fragmentation and enhanced energetic explosives such as HMX or CL-20.
Light Attack Bomb is a follow-on demonstration for the Small Smart Bomb to expand the SSB target set by demonstrating maneuver capability against ground mobile targets using an existing seeker for guidance.

The High Leverage Munitions (HLM) concepts are a class of next generation weapons designed to efficiently package small, highly lethal mini missiles of the future. They employ direct dispense technology being developed under WL/MN Low Cost Dispensing (LODIS) program as a means of high density loadouts for both internal and external carriage. This low observable/low drag container is capable of incremental or salvo dispensing and has virtual interface capability. Air bags are used to eject the mini missiles. The dispenser serves as a shipping/stores container. Electrical interface to the mini missiles is made via a single 1553 bus.

Specifications
Diameter	Six inches
Length	Six feet
Weight	250-lb
Warhead	steel case for penetration 50 lbs of high explosive
Guidance	Differential GPS/INS , Autonomous, all weather
Accuracy	three meters circular error probable (CEP) for surveyed target
Penetration	six feet of reinforced concrete