Joint Direct Attack Munition

GBU-31: Mk84 bomb fitted with JDAM
GBU-31: Mk84 bomb fitted with JDAM
Joint Direct Attack Munition (JDAM)
Use: Fixed target, precision strike, Moving Vehicle
Length: 9.9–12.75 feet (3.0–3.89 m)
Wingspan: 19.6 to 25 inches (500 to 630 mm)
Range: Up to 15 nautical miles (28 km)
Cost: $35,000+ for the GBU-38 $70,000+ for the GBU-31

The Joint Direct Attack Munition (JDAM) is a guidance kit that converts unguided gravity bombs, or "dumb bombs" into all-weather "smart" munitions. JDAM-equipped bombs are guided by an integrated inertial guidance system coupled to a Global Positioning System (GPS) receiver, giving them a published range of up to 15 nautical miles (28 km). The guidance system was developed by the United States Air Force and United States Navy, hence the "joint" in JDAM. The JDAM was meant to improve upon laser-guided bomb and imaging infrared technology, which can be hindered by bad ground and weather conditions. Laser designators are now being fitted to some JDAMs, because they can help attack certain types of targets.

Contents

Overview

The JDAM is not a weapon; rather it is a "bolt-on" for unguided gravity bombs consisting of a tail section with aerodynamic control surfaces, a strake kit, and a combined inertial guidance system and GPS guidance control unit. It is installed by Naval Ordnancemen or Air Force Munition Systems Specialists.

JDAM-equipped bombs range from 500 pounds (230 kg) to 2,000 pounds (910 kg).[1] When installed on a bomb, the JDAM kit is given a GBU (Guided Bomb Unit) nomenclature, superseding the Mark 80 or BLU (Bomb, Live Unit) nomenclature of the bomb to which it is attached.

History and development

The Air Force's initial bombing efforts during 1991's Operation Desert Storm suffered for the lack of an air-to-surface weapon that could work regardless of smoke, fog, dust, and cloud cover. Research, development, testing and evaluation (RDT&E) of an "adverse weather precision guided munition" began in 1992. Several proposals were considered, including a radical concept that used GPS. At the time, there were few GPS satellites and the idea of using satellite navigation for real-time weapon guidance was untested and controversial. To identify the technical risk associated with an INS/GPS guided weapon, the Air Force created in early 1992 a rapid-response High Gear program called the “JDAM Operational Concept Demonstration” (OCD) at Eglin Air Force Base. Honeywell, Interstate Electronics Corporation, Sverdrup Technology, and McDonnell Douglas were hired to help the USAF 46 Test Wing demonstrate the feasibility of a GPS weapon within one year. The OCD program fitted a GBU-15 guided bomb with an INS/GPS guidance kit and on 10 February 1993, dropped the first INS/GPS weapon from an Air Force F-16 on a target 88,000 feet (27 km) downrange. Five more tests were run in various weather conditions, altitudes, and ranges.[2] The OCD program demonstrated an 11-meter Circular Error Probable (CEP).

OCD First Flight Test of the first GPS guided weapon, a direct hit on the target, Eglin Air Force Base, 10 February 1993

The first JDAM kits were delivered in 1997, with operational testing conducted in 1998 and 1999. During testing, over 450 JDAMs were dropped achieving a system reliability in excess of 95% with a published accuracy under 10 metres (33 ft) CEP.[3] In addition to controlled parameter drops, the testing and evaluation of the JDAM also included "operationally representative tests" consisting of drops through clouds, rain and snow with no decrease in accuracy from clear weather tests. In addition, there have been tests involving multiple weapon drops with each weapon being individually targeted.[4]

JDAM and the B-2 Spirit stealth bomber made their combat debuts during Operation Allied Force. The B-2s, flying 30-hour, nonstop, round-trip flights from Whiteman Air Force Base, Missouri, delivered more than 650 JDAMs during Allied Force. An article published in a military acquisition journal in 2002 cites that "[d]uring Operation Allied Force ... B-2s launched 651 JDAMs with 96% reliability and hit 87% of intended targets..."[5] Due to the operational success of the original JDAM, the program expanded to the 500 pounds (230 kg) Mark 82 and 1,000 pounds (450 kg) Mark 83, beginning development in late 1999. As a result of lessons learned during Operation Enduring Freedom and Operation Iraqi Freedom, the Navy and Air Force are both pursuing enhancements to the kits such as improved GPS accuracy as well as a precision seeker for terminal guidance for use against moving targets.

JDAM bombs are inexpensive compared to alternatives such as cruise missiles. The original cost estimate was $40,000 each for the tail kits, but after competitive bidding, contracts were signed with McDonnell Douglas (later taken over by Boeing) for delivery at $18,000 each. Unit costs have since increased to $21,000 in 2004 and are expected to reach $31,000 by 2011.[6] For comparison, the newest Tomahawk cruise missile, dubbed the Tactical Tomahawk, costs nearly $730,000 a piece.[7][8]

Operational use

JDAMs loaded under the left wing of a F-16 Fighting Falcon with a LITENING II Targeting Pod visible beneath the fuselage

Guidance is facilitated through a tail control system and a GPS-aided inertial navigation system (INS). The navigation system is initialized by transfer alignment from the aircraft that provides position and velocity vectors from the aircraft systems. Once released from the aircraft, the JDAM autonomously navigates to the designated target coordinates. Target coordinates can be loaded into the aircraft before takeoff, manually altered by the aircrew in flight prior to weapon release, or entered by a datalink from onboard targeting equipment, such as the LITENING II or "Sniper" targeting pods. In its most accurate mode, the JDAM system will provide a minimum weapon accuracy CEP of 13 meters or less when a GPS signal is available, though Boeing and the Air Forces report less than 10 meters CEP in testing. If the GPS signal is jammed or lost, the JDAM can still achieve a 30 meter CEP or less for free flight times up to 100 seconds.[9]

The introduction of GPS guidance to weapons brought several improvements to air-to-ground warfare. The first is a real all-weather capability since GPS is not affected by rain, clouds, fog, smoke, or man-made obscurants. Previous precision guided weapons relied on seekers using infrared, visual light, or a reflected laser spot to “see” the ground target. These seekers were not effective when the target was obscured by fog and low altitude clouds and rain (as encountered in Kosovo), or by dust and smoke (as encountered in Desert Storm).

The second advantage is an expanded launch acceptance region (LAR). The LAR defines the region that the aircraft must be within to launch the weapon and hit the target. Non-GPS based precision guided weapons using seekers to guide to the target have significant restrictions on the launch envelope due to the seeker field of view. Some of these systems (such as the Paveway I, II, and II) must be launched so that the target remains in the seeker field of view throughout the weapon trajectory (or for lock-on-after-launch engagements, the weapon must be launched so that the target is in the field of view during the terminal flight). This requires the aircraft to fly generally straight at the target when launching the weapon. This restriction is eased in some other systems (such as the GBU-15 and the AGM-130) through the ability of a Weapon System Operator (WSO) in the aircraft to manually steer the weapon to the target. Using a WSO requires a data link between the weapon and the controlling aircraft and requires the controlling aircraft to remain in the area (and possibly vulnerable to defensive fire) as long as the weapon is under manual control. Since GPS-based flight control systems know the weapon current location and the target location, these weapons can autonomously adjust the trajectory to hit the target. This allows the launch aircraft to release the weapon at very large off-axis angles including releasing weapons to attack targets behind the aircraft.

The third advantage is a true “fire-and-forget” capability in which the weapon does not require any support after being launched. This allows the launching aircraft to leave the target area and proceed to its next mission immediately after launching the GPS guided weapon.

Another important capability provided by GPS-based guidance is the ability to completely tailor a flight trajectory to meet criteria other than simply hitting a target. Weapon trajectories can be controlled so that a target can be impacted at precise headings and vertical angles. This provides the ability to impact perpendicular to a target surface and minimizing the angle of attack (maximizing penetration), detonating the warhead at a the optimum angle to maximize the warhead effectiveness, having the weapon fly into the target area from a different heading than the launch aircraft (decreases the risk of detection of the aircraft). GPS also provides an accurate time source common to all systems. This allows multiple weapons to loiter and impact targets at preplanned times and intervals.

In recognition of these advantages, most weapons including the Paveway, GBU-15, and the AGM-130 have been upgraded with a GPS capability. This enhancement combines the flexibility of GPS with the superior accuracy of seeker guidance.

Despite their precision, JDAM employment does not come without risk. On 5 December 2001, a JDAM dropped by a B-52 in Afghanistan nearly killed Hamid Karzai, while he was leading anti-Taliban forces near Sayd Alim Kalay alongside a US Army Special Forces (SF) team. A large force of Taliban soldiers had engaged the combined force of Karzai's men and their American SF counterparts, nearly overwhelming them. The SF commander requested Close Air Support (CAS) to strike the Taliban positions in an effort to stop their advance. A JDAM was subsequently dropped, but instead of striking the Taliban positions, it struck the Afghan/American position. An investigation of the incident determined that the U.S. Air Force Tactical Control Party (TACP) attached to the Special Forces team had changed the battery in the GPS receiver at some point during the battle, thereby causing the device to return to "default" and "display its own coordinates." Not realizing that this had occurred, the TACP relayed his own coordinates to the delivery aircraft.[10][11]

Upgrades

U.S. military experience during Operation Enduring Freedom and Operation Iraqi Freedom highlighted the need for additional capability in one package, resulting in ongoing program upgrades to place a precision terminal guidance seeker in the JDAM kit.[12] The Laser JDAM (LJDAM), as this upgrade is known, adds a laser seeker to the nose of a JDAM equipped bomb, giving the ability to engage moving targets to the JDAM. The Laser Seeker is a cooperative development between Boeing Integrated Defense Systems and Israel's Elbit Systems.[13] It is called Precision Laser Guidance Set (PLGS) by Boeing and consists of the Laser Seeker itself, now known as DSU-38/B, and a wire harness fixed under the bomb body to connect the DSU-38/B with the tailkit. During FY2004, Boeing and the U.S. Air Force began testing of the laser guidance capability for JDAM, with these tests demonstrating that the system is capable of targeting and destroying moving targets.[14] This dual guidance system retains the ability to operate on GPS/INS alone, if laser guidance is unavailable, with the same accuracy of the earlier JDAM.

On 11 June 2007, Boeing announced that it had been awarded a $28 million contract by the U.S. Air Force to deliver 600 laser seekers (400 to the Air Force and 200 to the Navy) by June 2009.[15] According to the Boeing Corporation, in tests at Nellis Air Force Base, Nevada, Air Force F-16 Fighting Falcons and F-15E Strike Eagles dropped twelve (12) 500 pounds (230 kg) LJDAMs that successfully struck high-speed moving targets. Using onboard targeting equipment, the launch aircraft self-designated, and self-guided their bombs to impact on the targets. In addition to the LJDAM kits, Boeing is also testing under a Navy development contract, an anti-jamming system for the JDAM, with development expected to be completed during 2007, with deliveries to commence in 2008.[16] The system is known as the Integrated GPS Anti-Jam System (IGAS). Boeing announced on 15 September 2008, that it had conducted demonstration flights with the LJDAM loaded aboard a B-52H.[17]

On 24 July 2008 Germany signed a contract with Boeing to become the first international customer of LJDAM. Deliveries for the German Luftwaffe will begin in mid-2009. The order also includes the option for further kits in 2009.[18]

Integration

JDAMs loaded onto a Multiple Ejector Rack under the wing of a B-52H Stratofortress

Current

JDAM is currently compatible with:

Planned

Follow-on integration efforts are currently underway or planned to evaluate compatibility with:

Past

JDAM was compatible with the following aircraft:

Export

The U.S. Government has approved the JDAM for export sale under the Arms Export Control Act, though in limited numbers to only a few countries. Outstanding requests for purchase are under review.

Export customers

Export requests

General characteristics

Variants

USAF artist rendering of JDAM kits fitted to Mk 84, BLU-109, Mk 83, and Mk 82 iron bombs.

Similar systems

See also

Notes

  1. ↑ "JDAM continues to be warfighter's weapon of choice". http://www.af.mil/news/story.asp?storyID=123017613. Retrieved 2007-07-27. 
  2. ↑ INS/GPS Operational Concept Demonstration (OCD) High Gear Program, IEEE Aerospace and Electronic Systems Magazine, 8 August 1994
  3. ↑ (PDF) JDAM: The Kosovo Experience and DPAS. The Boeing Company, Charles H. Davis. 19 April 2000. http://guidebook.dcma.mil/38/dpas/12DavisPres.pdf. Retrieved 2007-09-01 
  4. ↑ The Boeing Company (17 September 2003). "U.S. Air Force B-2 Bomber Drops 80 JDAMS in Historic Test". Press release. http://www.boeing.com/defense-space/missiles/jdam/news/2003/q3/nr_030917o.html. Retrieved 2007-09-02. 
  5. ↑ Myers, Dominique (2002). "Acquisition Reform-Inside The Silver Bullet" (PDF). Acquisition Review Journal IX, no. 2 (Fall 2002): 312–322. http://www.dau.mil/pubs/arq/2002arq/MyersFL02.pdf. Retrieved 2007-09-01 
  6. ↑ DEPARTMENT OF THE NAVY FISCAL YEAR (FY) 2006/FY 2007 BUDGET ESTIMATES
  7. ↑ "The JDAM Revolution" article by Peter Grier in Air Force Online, the journal of the Air Force Association, September, 2006
  8. ↑ "BGM-109 Tomahawk: Variants". http://www.globalsecurity.org/military/systems/munitions/bgm-109-var.htm. Retrieved 2007-07-27. 
  9. ↑ "USAF Factsheet: JOINT DIRECT ATTACK MUNITIONS". http://www.af.mil/factsheets/factsheet.asp?fsID=108. Retrieved 2007-07-27. 
  10. ↑ "Killing Your Own: The Problem of Friendly Fire During the Afghan Campaign". http://www.cdi.org/terrorism/killing.cfm. Retrieved 2007-07-27. 
  11. ↑ uni-bielefeld.de Why-Because analysis (p. 9).
  12. ↑ "Dual Mode Guided Bomb". http://www.deagel.com/Tactical-Bombs/DMGB_a000937001.aspx. Retrieved 2007-07-27. 
  13. ↑ U.S. Backs Israeli Munitions Upgrades, Defence News, May 3 2010
  14. ↑ "Boeing Scores Direct Hit in Laser JDAM Moving Target Test". http://www.boeing.com/news/releases/2006/q3/060711a_nr.html. Retrieved 2007-07-27. 
  15. ↑ The Boeing Company (11 June 2007). "Boeing Awarded Laser JDAM Contract". Press release. http://www.boeing.com/defense-space/missiles/jdam/news/2007/q2/070611c_nr.html. Retrieved 2007-09-02. 
  16. ↑ The Boeing Company (18 June 2007). "Boeing Completes JDAM Anti-Jamming Developmental Flight Test Program". Press release. http://www.boeing.com/defense-space/missiles/jdam/news/2007/q2/070618a_nr.html. Retrieved 2007-09-02. 
  17. ↑ Boeing Press Release, 15 September 2008
  18. ↑ [1], Boeing.com - Germany becomes the first international customer of LDJAM
  19. ↑ "boeing.com Boeing JDAM Wins Australian Competition". http://www.boeing.com/ids/news/2005/q4/nr_051019s.html. Retrieved 2007-07-27. 
  20. ↑ "First International JDAM Sale: Boeing to Integrate Weapon on Israeli Aircraft". http://www.boeing.com/defense-space/missiles/jdam/news/2000/news_release_000601n.htm. Retrieved 2007-07-27. 
  21. ↑ "global security.org". http://www.globalsecurity.org/military/systems/munitions/jdam-history.htm. Retrieved 2007-07-27. 
  22. ↑ 航空ファン 2008-12 P118
  23. ↑ "Dutch secretary of defense details plan for purchase of JDAM's". http://www.mindef.nl/actueel/toespraken/2003/4/091203_airpowersymposium.aspx. Retrieved 2007-07-27. 
  24. ↑ "Norway Signs Contract for Boeing JDAM". http://www.boeing.com/defense-space/missiles/jdam/news/2006/q1/060220a_nr.html. Retrieved 2007-07-27. 
  25. ↑ "Gates says Washington to sell smart bombs to Saudi Arabia". http://www.haaretz.com/hasen/spages/850746.html. Retrieved 2007-07-27. 
  26. ↑ "FMS: Third Phase of Finnish F/A-18 MLU". http://www.deagel.com/news/FMS-Third-Phase-of-Finnish-FA-18-MLU_n000001010.aspx. Retrieved 2007-07-27. 
  27. ↑ "FMS: Greece - F-16C/D Munitions". http://www.asd-network.com/press_detail/10501/FMS:_Greece_-_F-16C/D_Munitions.htm. Retrieved 2007-07-27. 
  28. ↑ "Komutanlar Anadolu Kartali'nda (In Turkish)". http://www.sage.tubitak.gov.tr/haberler%5Cmilliyet%5C2%5C2.htm. Retrieved 2009-04-13. 
  29. ↑ "Anadolu Kartali'na Yerli Bilim Katkisi (In Turkish)". http://www.milligazete.com.tr/haber/anadolu-kartalina-yerli-bilim-katkisi-23260.htm. Retrieved 2009-04-13. 

References

External links

Lists relating to aviation
General
Timeline of aviation · Aircraft (manufacturers) · Aircraft engines (manufacturers) · Rotorcraft (manufacturers) · Airlines (defunct) · Airports · Civil authorities · Museums
Military
Air forces · Aircraft weapons · Experimental aircraft · Missiles · Unmanned aerial vehicles (UAVs)
Accidents/incidents
General · Commercial (airliners) · Military
Records
Airspeed · Altitude · Distance · Endurance · Most-produced aircraft