Joint Direct Attack Munition

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File:GBU-31 xxl.jpg
GBU-31: Mk84 bomb fitted with JDAM
Joint Direct Attack Munition (JDAM)
Mission: Close air support, interdiction, offensive counterair, suppression of enemy air defense, naval anti-surface warfare, amphibious strike
Length: 9 ft 11 in – 12 ft 8 in
(3.0 to 3.9 m)
Wingspan: 1 ft 7 in – 2 ft 1 in
(483 to 635 mm)
Range: Up to 15 nm (24 km)

The Joint Direct Attack Munition (JDAM) is a low-cost guidance kit that converts existing unguided gravity bombs, or "dumb bombs", into accurate, all-weather "smart" munitions. JDAM equipped bombs are guided to their target by an integrated inertial guidance system coupled with a Global Positioning System (GPS) receiver for enhanced accuracy, giving them a published range of up to 15 nautical miles from the release point. JDAM is a joint United States Air Force and United States Navy program. It is in service with the U.S. Air Force, U.S. Navy and the U.S. Marine Corps.

Contents

Overview

The JDAM is not a stand alone weapon system, rather it is a "bolt-on" upgrade for unguided gravity bombs that is installed in the field by aircraft armorers. JDAM equipped bombs range in size from 500 lbs (225 kg) to 2000 lbs (900 kg).[1] The kit is compatible with the entire family Mk-80 family of general purpose bombs, as well as the corresponding BLU penetrator warheads. JDAM consists of a tail section with integrated aerodynamic control surfaces, a stabilizing strake kit, and a combined inertial guidance system and GPS guidance control unit. JDAM enables accurate delivery against high priority fixed and relocatable targets from both fighter and bomber aircraft.

History & Development

Desert Storm highlighted a shortfall in air-to-surface weapon capability. Limited visibility of the ground caused by smoke, fog, dust and cloud cover limited the employment of precision guided munitions. Unguided weapon accuracy was also degraded when delivered from medium and high altitudes. Research and development of an "adverse weather precision guided munition" began in 1992. The first JDAMs were delivered in 1997 with operational testing conducted in 1998 and 1999. More than 450 JDAMs were dropped during testing, recording an unprecedented 95 percent system reliability while achieving a 9.6 meter accuracy rate. JDAM performance has been demonstrated in operationally representative tests including drops through clouds, rain and snow. These tests included a B-2 Spirit releasing 16 JDAMs on a single pass against multiple targets in two separate target areas.

JDAM and the B-2 made their combat debuts during Operation Allied Force. The B-2s, flying 30-hour, nonstop, roundtrip flights from Whiteman Air Force Base, Missouri, delivered more than 600 JDAMs during Allied Force. Military sources say that "During Operation Allied Force, March 29 through June 9, 1999, B-2s launched 651 JDAMs with 96 percent reliability and hit 87 percent of intended targets..." Growth of the JDAM family of weapons expanded to the 500 pound (230 kg) Mark 82 bomb version, which began development in late 1999. Also, the Navy is currently studying the effects of adding enhancements such as improved GPS accuracy as well as a precision seeker for terminal guidance for use against moving targets and additional warheads.

On September 10, 2003, a B-2 Spirit bomber successfully released eighty (80) inert 500 pound (230 kg) JDAM munitions on a single sortie, demonstrating a saturation precision attack capability not thought possible in the early days of smart weapons.

JDAM bombs are cheap compared to alternatives such as cruise missiles. The original estimate was $40,000 each for tail kits, but after competitive bidding, contracts were signed with McDonnell Douglas (later overtaken by Boeing) for delivery at $18,000 each. For instance, the newest Tomahawk, dubbed the Tactical Tomahawk, costs nearly $730,000 apiece, and despite its tremendous operational capabilities will not replace manned aircraft carrying JDAMs, and other "smart munitions."[2][3]

Operational Use

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 datalink from onboard targeting equipment, such as the LITENING II Targeting Pod. In its most accurate mode, the JDAM system will provide a weapon Circular Error Probable (CEP) of 13 meters or less (some Boeing sources report less than 10 meters CEP) when a GPS signal is available. 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.[4]

JDAM can be launched from very-low to very-high altitudes in a dive, toss-and-loft, or in straight-and-level flight, with an on-axis or off-axis delivery. JDAM enables multiple weapons to be directed against single or multiple targets on a single pass. The JDAM system permits variable fuzing, from air-burst through contact- and penetration-fuzing, making it a versatile guidance system.[4] Fuzing must be set prior to takeoff, as the aircrew have no way to adjust this in flight.

Despite their precision, JDAMs have been involved in "friendly fire" incidents in which U.S. troops were killed. On December 5, 2001, a JDAM dropped by a B-52 in Afghanistan nearly killed Hamid Karzai, now the country's president, near Sayd Alim Kalay. Three U.S. troops and five allied Afghans were killed, with over forty injured. The JDAM's GPS battery had been changed, apparently causing the incident. "The receiver defaults to display its own coordinates after the battery is replaced, something the operator either did not know or overlooked in the heat of battle."[5]

Upgrades

U.S. military experience during Operation Enduring Freedom and Operation Iraqi Freedom highlighted the need for an even more accurate delivery of bombs.[6] The Laser JDAM adds a laser seeker to the nose of a JDAM equipped bomb, alowing for highly precise terminal guidance, allowing for a CPE of 3 meter, with the ability to strike a moving target. During FY2004, the Boeing and the U.S. Air Force began testing of the laser guidance capability for JDAM. These tests demonstarted that the system is capable of targeting and destroying moving targets. [7] The weapon retains the ability to operate on GPS/INS alone, if laser guidance is unavailable, with the same accuracy of the earlier JDAM.

Integration

File:JDAM GBU30 MER.jpg
JDAMs loaded onto a Multiple Ejector Rack under the wing of a B-52H Stratofortress

JDAM is currently compatible with:

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

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

  • Primary function: Guided air-to-surface weapon
  • Contractor: Boeing
  • Length: (JDAM and warhead) GBU-31 (v) 1/B: 152.7 in (3879 mm); GBU-31 (v) 3/B: 148.6 in (3774 mm); GBU-32 (v) 1/B: 119.5 in (3035 mm)
  • Launch weight: (JDAM and warhead) GBU-31 (v) 1/B: 2,036 lb (925 kg); GBU-31 (v) 3/B: 2,115 lb (961 kg); GBU-32 (v) 1/B: 1,013 lb (460 kg)
  • Wingspan: GBU-31: 25 in (635 mm); GBU-32: 19.6 in (498 mm)
  • Range: Up to 15 miles (24 km)
  • Ceiling: 45,000 ft (13,700 m)
  • Guidance system: GPS/INS
  • Unit cost: Approximately $21,000 per tailkit (FY 01 dollars)
  • Date deployed: 1999
  • Inventory: The tailkit is in full-rate production. Projected inventory is approximately 240,000 total, 158,000 for the US Air Force and 82,000 for the US Navy. (As of October 2005)

Variants

File:JDAM family (1).jpg
USAF artist rendering of JDAM kits fitted to Mk 84, BLU-109, Mk 83, and Mk 82 iron bombs.
  • GBU-31(V)1/B (USAF) Mk-84
  • GBU-31(V)2/B (USN/USMC) Mk-84
  • GBU-31(V)3/B (USAF) BLU-109
  • GBU-31(V)4/B (USN/USMC) BLU-109
  • GBU-32(V)1/B (USAF) Mk-83
  • GBU-32(V)2/B (USN/USMC) Mk-83
  • GBU-35(V)1/B (USN/USMC) BLU-110
  • GBU-38/B (USAF) Mk-82,(USN/USMC)Mk-82 and BLU-111

See also

Notes

  1. ^ JDAM continues to be warfighter's weapon of choice
  2. ^ "The JDAM Revolution" article by Peter Grier in Air Force Online, the journal of the Air Force Association, September, 2006
  3. ^ "BGM-109 Tomahawk: Variants"
  4. ^ a b USAF Factsheet: JOINT DIRECT ATTACK MUNITIONS
  5. ^ [1]
  6. ^ Dual Mode Guided Bomb
  7. ^ Boeing Scores Direct Hit in Laser JDAM Moving Target Test
  8. ^ First International JDAM Sale: Boeing to Integrate Weapon on Israeli Aircraft
  9. ^ global security.org
  10. ^ boeing.com Boeing JDAM Wins Australian Competition
  11. ^ Norway Signs Contract for Boeing JDAM
  12. ^ Dutch secretary of defense details plan for purchase of JDAM's
  13. ^ FMS: Third Phase of Finnish F/A-18 MLU
  14. ^ FMS: Pakistan New F-16C/D Block 50/52 Aircraft
  15. ^ FMS: Singapore Potential F-15 Weapons, Logistics and Training Package
  16. ^ FMS: Greece - F-16C/D Munitions

References

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