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Guided Bomb Units

posted by Jiri Wagner

The Army began research into laser guidance systems in 1962 and by 1967 the Air Force had conducted a competitive evaluation leading to full development of the BOLT-117. Although its 1968 combat evaluation was considered highly successful, it was decided to discontinue use of the BOLT-117 in favor of a 2,000-pound LGB called the GBU-10. The larger bomb had proven twice as accurate and had far more explosive power. While production of the BOLT-117 was limited, its impact on airpower was revolutionary. Laser guidance kits turned standard "dumb" ordnance into "smart bombs," yielding a 100-fold increase in effectiveness compared with free-fall, unguided bombs.

Texas Instruments BOLT-117 Laser Guided Bomb

The BOLT-117 (BOmb, Laser Terminal-117) was the world's first laser guided bomb (LGB). It consisted of a standard 750-pound bomb case with a KMU-342 laser guidance and control kit.

 

Guided Bomb Unit-15 (GBU-15)

  The GBU-15 bomb is an unpowered, glide weapon used to destroy high value enemy targets. It is designed to be used with F-15E and F-111F aircraft. The weapon consists of modular components that are attached to either an MK-84 or BLU-109 penetrating warhead. Each weapon has five components -- a forward guidance section, warhead adapter section, control module, airfoil components and a weapon data link. The guidance section is attached to the nose of the weapon and contains either a television guidance system for daytime or an imaging infrared system for night or limited, adverse weather operations. A data link in the tail section sends guidance updates to the control aircraft that enables the weapon systems operator to guide the bomb by remote control to its target. An external electrical conduit extends the length of the warhead which attaches the guidance adapter and control unit. The conduit carries electrical signals between the guidance and control sections. The umbilical receptacle passes guidance and control data between cockpit control systems of the launching aircraft and the weapon prior to launch. The rear control section consists of four wings are in an "X"-like arrangement with trailing edge flap control surfaces for flight maneuvering. The control module contains the autopilot, which collects steering data from the guidance section and converts the information into signals that move the wing control surfaces to change the weapon's flight path. The GBU-15 may be used in direct or indirect attack. In a direct attack, the pilot selects a target before launch, locks the weapon guidance system onto it and launches the weapon. The weapon automatically guides itself to the target, enabling the pilot to leave the area. In an indirect attack, the weapon is guided by remote control after launch. The pilot releases the weapon and, via remote control, searches for the target. Once the target is acquired, the weapon can be locked to the target or manually guided via the date-link system. This highly maneuverable weapon has an optimal, low-to-medium altitude delivery capability with pinpoint accuracy. It also has a standoff capability. Desert Storm F-111F pilots used GBU-15 glide bombs to seal flaming oil pipeline manifolds sabotaged by Saddam Hussein's troops. The Air Force Development Test Center, Eglin AFB, Fla., began developing the GBU-15 in 1974. It was a product improvement of the early guided bombs used during the Southeast Asia conflict. Flight testing of the weapon began in 1975. The GBU-15 with television guidance, completed full-scale operational test and evaluation in November 1983. In February 1985, initial operational test and evaluation was completed on the imaging infrared guidance seeker. In December 1987, the program management responsibility for the GBU-15 weapon system transferred from the Air Force Systems Command to the Air Force Logistics Command. The commands merged to become the Air Force Materiel Command in 1992.  

Guided Bomb Unit-27 (GBU-27)

The Guided Bomb Unit-27 (GBU-27) is a GBU-24 modified for delivery by the F-117 stealth fighter. The operator illuminates a target with a laser designator and then the munition guides to a spot of laser energy reflected from the target. It uses a 2,000-pound penetrating warhead against hard targets. The GBU-27 was used in Operation Desert Storm. According to the Air Force, the GBU-27 hit 70 percent of its targets. The GBU-27 was designed specifically for use by the F-117's advanced target acquisition/designator system. The GBU-27 uses a BLU-109 improved performance 2,000 pound bomb developed in 1985 under the project name HAVE VOID. The BLU-109 was designed for use against hardened structures and features a high-strength forged steel case and a new delayed-action tail fuze. It carries 550 pounds of high explosives and can penetrate more than six feet of reinforced concrete. The GBU-27 uses a modified Paveway II guidance control unit which provides "terminal trajectory shaping" for optimum impact angle against various target structures. For example, it will hit an aircraft shelter with a vertical impact, but make a horizontal approach to a bridge support. A Paveway II tail assembly with folding wings completes the bomb. The F-117 can carry two GBU-27s in two weapons bays and is reportedly capable of hitting a one square meter target from an altitude of 25,000 feet.  

JDAM - Joint Direct Attack Munition (GBU-31)

The Joint Direct Attack Munition (JDAM) GBU-31 is a tailkit under development to meet both USAF and Navy needs, with the Air Force as the lead service. The program will produce a weapon with high accuracy, all-weather, autonomous, conventional bombing capability. JDAM will upgrade the existing inventory of general purpose and penetrator unitary bombs, and a product improvement may add a terminal seeker to improve accuracy. JDAM is not intended to replace any existing weapon system; rather, it is to provide accurate delivery of general purpose bombs in adverse weather conditions. The JDAM will upgrade the existing inventory of Mk-83 1,000- and Mk-84 2,000-pound general purpose unitary bombs and the 2,000-pound hard target penetrator bomb by integrating a guidance kit consisting of an inertial navigation system/global positioning system guidance kit. The 1,000-pound variant of JDAM is designated the GBU-31, and the 2,000-pound version of the JDAM is designated the GBU-32. JDAM variants for the Mk-80 250-pound and Mk-81 500-pound bombs are designated GBU-29 and GBU-30, respectively. The JDAM will be continuously updated by aircraft avionics systems prior to release. Once released, the bomb's INS/GPS will take over and guide the bomb to its target regardless of weather. Guidance is accomplished via the tight coupling of an accurate GPS with a 3-axis INS. The Guidance Control Unit provides accurate guidance in both GPS-aided INS modes of operation and INS-only modes of operation. This inherent JDAM capability will counter the threat from near-term technological advances in GPS jamming. The weapon system allows launch from very low to very high altitude and can be launched in a dive, toss, loft or in straight and level flight with an on-axis or off-axis delivery. JDAM also allows multiple target engagements on a single pass delivery. JDAM provides the user with a variety of targeting schemes, such as preplanned and inflight captive carriage retargeting. JDAM is being developed by Lockheed Martin and Boeing [McDonald Douglas] and will be operational by 1998. In October 1995, the Air Force awarded a contract for EMD and for the first 4,635 JDAM kits at an average unit cost of $18,000, less than half the original $40,000 estimate. As a result of JDAM's pilot program status, low-rate initial production was accelerated nine months, to the latter half of FY 1997. JDAM will be carried on virtually all Air Force fighters and bombers, including the B-1, B-2, B-52, F-15E, F-16, F-22, F-117, AND F/A-18. JDAM was certified as operational capable on the B-2 in July 1997. The JDAM program is nearing the end of its development phase. More than 250 flight tests involved five Air Force and Navy aircraft. The 11 Feb 1998 drop from a B-1B was the 122nd guided JDAM launch. Early operational capability JDAMs have been delivered to Whiteman AFB, Mo., and low-rate, initial production JDAM deliveries begin on 02 May 1998. The JDAM product improvement program may add a terminal seeker for precision guidance and other system improvements to existing JDAMs to provide the Air Force with 3-meter precision and improved anti-jamming capability. The Air Force is evaluating several alternatives and estimates that the seeker could be available for operations by 2004. The seeker kit could be used by both the 2,000-pound blast fragmentation and penetrator JDAMs.  

 

Press Releases

Boeing Awarded Laser JDAM Contract / 2007-06-11