Joint Direct Attack Munition

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Image:GBU-31 xxl.jpg GBU-31: Mk84 bomb fitted with JDAM
Joint Direct Attack Munition (JDAM)
Primary function:	GPS/INS smart tailkit that fits on general purpose unguided bombs
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 miles (24 km)

The Joint Direct Attack Munition (JDAM) is a guidance tail kit that converts existing unguided free-fall bombs into accurate, adverse-weather "smart" munitions. With the addition of a new tail section that contains an inertial guidance system and a Global Positioning System guidance control unit, JDAM vastly improves the accuracy of otherwise unguided, general purpose bombs in any weather condition. JDAM is a joint United States Air Force and United States Navy program.

1 Overview
2 Integration
3 General characteristics
4 Variants
- 4.1 Laser JDAM
5 Notes
6 See also
7 External links

[edit] Overview

JDAM is a guided air-to-surface weapon that is used with Mark 80 series of bombs, which range in size from 500 to 2,000 pound (900 kg) warheads as the payload. JDAM enables employment of accurate air-to-surface weapons against high priority fixed and relocatable targets from fighter and bomber aircraft. 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 before weapon release, and automatically entered through target designation with onboard aircraft sensors. In its most accurate mode, the JDAM system will provide a weapon circular error probable of 13 meters or less (some Boeing sources report less than 10 meters CEP) during free flight when GPS data is available. If GPS data is denied, the JDAM will achieve a 30 meter CEP or less for free flight times up to 100 seconds with a GPS quality handoff from the aircraft.

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.

Desert Storm highlighted a shortfall in air-to-surface weapon capability. Adverse weather conditions limited 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..."^{[citation needed]}. 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, a precision seeker for terminal guidance 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.

[edit] Integration

JDAM is currently compatible with:

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

[edit] 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)

[edit] Variants

GBU-29 based on 250-lb Mk 81 (cancelled)
GBU-30 based on 500-lb Mk 82 or BLU-111/B
GBU-31 based on 2000-lb Mk 84 or BLU-109
GBU-32 based on 1000-lb Mk 83
GBU-35 based on 1000-lb BLU-110
GBU-38 based on 500-lb Mk 82

[edit] Laser JDAM

As of July 2006, a development program is underway to provide a terminal laser guidance capability for JDAM which will enable it to engage moving targets as well as increasing accuracy against fixed targets if laser designation is available.<ref>Boeing Scores Direct Hit in Laser JDAM Moving Target Test</ref> The weapon will retain the ability to operate on GPS/INS alone if necessary.