Planned JDAM upgrade boosts accuracy to 10 Feet: Navy completes development of new seeker that guides bombs with images. (Analysis).
The Joint Direct Attack Munition is a 1,000-pound or 2,000-pound free-falling bomb with a strap-on Global Positioning System/Inertial Navigation System (GPS/INS) guidance kit.
JDAM's accuracy is nearly 43 feet in the GPS/INS mode and 100 feet with INS alone. The new seeker, using uncooled imaging infrared focal plane array technology, would increase the accuracy to about 10 feet. The system is called Damask, an acronym for direct attack munition affordable seeker. Each system is expected to cost $12,700, said Michael Dietchman, director of strike technology at the Office of Naval Research. Each JDAM guided bomb costs about $20,000.
Air - to - surface weapon accuracy is defined by circular error probable, or CEP. That is the radius of a circle within which 50 percent of the weapons will strike. The smaller the CEP, the greater the weapon's accuracy. The JDAM CEP is 13 meters. Dietchman said that the addition of Damask to JDAM lowers the CEP to three meters (about 10 feet).
Three-meter accuracy is achievable with laser-guided bombs, which can only be used in clear weather with direct line-of-sight to the target, and require a dedicated designator. JDAM is less accurate but often a preferred choice, because it's satellite-guided, so it works in bad weather.
The Office of Naval Research (ONR) developed and tested the Damask seeker and has turned over the system to Navy weapon acquisition officials. Damask could soon be used to upgrade JDAMs currently in production at the Boeing Co.
"The acquisition part of the Navy is working with Boeing to look at the design and where to go from here," said Dietchman in a briefing to the Precision Strike Association. "The science and technology proved that it can work. Now it's in the hands of the acquisition community."
The Navy and the Air Force collectively could buy anywhere between 20,000 and 100,000 JDAMs during the next several years. These weapons were widely used in the 1999 air war over Kosovo and the campaign over Afghanistan this fall. JDAMs are compatible with Air Force B-2, B-52 and B-1 bombers, F-16C/D fighter aircraft, and with Navy F/A-18C/D fighter aircraft.
On the question on whether Damask could be viewed as an alternative to GPS, "one must be careful to distinguish between midcourse guidance and terminal guidance," said Gil Graff, program manager for weapons science and technology at ONR. The Damask only is an alternative for terminal guidance. Guidance accuracy, he said, is limited by the capabilities of GPS and by the initial target location error (TLE). An imaging seeker such as Damask can achieve "substantial improvement in the final accuracy [compared to] inertially guided weapons," said Graff.
He said he expects that this technology will have applications beyond JDAM. "While the initial focus of Damask was for JDAM improvement, we believe that the technology will support much smaller weapons--such as the Army Hellfire missile and the Air Force Small Smart Bomb and [other weapons] as small as 2.75-inch rockets.
"The real power of an imaging weapon," he said, "is that it allows the munition size to be reduced substantially for a given level of damage."
In his briefing, Dietchman noted that, if the GPS signal were jammed, Damask would be able to guide JDAM to the target nonetheless.
During tests last year, JDAM weapons, equipped with the Damask, successfully hit targets when the GPS signal was jammed, he said.
The Damask has been in development for three years. In 1998, the Raytheon Systems Co. received an $11 million Navy contract to work on the uncooled focal plane array technology. The detector in Damask is a thermal imaging IR camera produced by Raytheon for use in the night-vision system of the 2000 Cadillac Deville.
The upgrade kit includes a seeker mounted on the nose of the JDAM and processing electronics in the tail assembly.
Before a mission, an image of the target taken from infrared, visual, synthetic aperture radar, satellite photograph or other source is used to make a target template, which is loaded into Damask.
The target template can be created on a PC and loaded into Damask before aircraft launch. A template also can be downloaded to the aircraft from a reconnaissance unmanned aircraft or a satellite, or can be generated from the launch aircraft's onboard sensors and loaded into the weapon during the mission.
For most of the mission, guidance is exclusively by GPS/INS. Then, when the weapon is a few kilometers from the target, Damask can be used to supplement GPS. It looks at the target for a second or two and compares what it sees with the target template that's been loaded. If necessary, it updates the JDAM guidance unit.
A Damask prototype called GR-2 was tested a year ago at the Navy's air warfare range in China Lake, Calif. The test was designed to duplicate a GPS-jamming scenario and measure the effect Damask would have in improving the JDAM accuracy, Dietchman said.
The launch platform was an F-16 Fighting Falcon from Edwards Air Force Base. Accompanying the shooter aircraft was a two-seat F-16 flying chase.
The pilot released the weapon at a slant range of about six miles, altitude of 28,000 feet (mean sea level) and speed of 0.8 Mach. From the point of launch, the JDAM received no GPS signals, navigating solely on INS. The GR-2's target was a square aluminum plate. About 1,800 meters from the target, the Damask signal processor compared the target-area view through the IR seeker with a target-area template that had been loaded before flight, and then sent a correctional signal to the JDAM's tail-control surfaces, said Dietchman. "Five seconds later, the weapon punched a hole in the target."
RELATED ARTICLE: Pentagon Panel: Targeting Far From Perfect
U.S. military precision-bombing skills and capabilities have advanced in recent years, but there still is much room for improvement, said a Pentagon advisory panel.
Among the shortcomings that hinder U.S. air-to-ground precision-strike missions, the panel said, are unreliable target identification technologies and difficulties in defeating enemy deception tactics.
The Defense Science Board began a study on precision targeting about a year ago and has briefed its findings to senior Pentagon officials in recent months. The DSB recommendations will focus, among other things, on the need to share targeting data among the military services and to expedite development of advanced sensors for intelligence collection, said Diane Wright, assistant director for air warfare, at the office of the undersecretary of defense for acquisition, technology and logistics.
"We are very good at precision strike," she told a conference of the Precision Strike Association. "We have laser designators to guide weapons down airshafts and through windows." However, she added, "There is plenty of room for problems in this very complicated process."
These problems include the ability of U.S. aircrews to positively identify targets that are not in visual range and to hit moving targets even when they hide under cover, concealment and decoys.
The DSB said that the Defense Department should focus on developing a capability to link a "targeting database" of precise geographic coordinates with the sensors on reconnaissance or strike platforms.
Ideally, said Wright, a pilot would be able to point and click on a digital map and automatically receive that target's coordinates from the database. She called that capability a "gridlock" system.
The National Imagery and Mapping Agency manages the so-called digital point positioning database, or DPPDB. It is the Defense Department's primary source for targeting information and imagery for GPS-guided weapons.
The gridlock would automate the "geo-registration process for both still imagery and motion imagery," said Wright. The goal would be to link that process to surveillance and tactical platforms, she said. "If you can tie the platform sensors to the related PPDB database, you can establish a relationship, so you can get PGM-quality target coordinates, just by pointing at the target on the tactical imagery."
Every platform would lock to the same grid, she said, "so you can share target coordinates without the need for imagery, therefore reducing demand for wideband communications."
This technology, she said, could be transitioned to the Joint Strike Fighter and might be tested with the Predator unmanned aircraft motion imagery.
According to one industry official, the growing emphasis on "open architectures" in military workstations used for targeting missions will help the services share new software applications constantly being developed by the intelligence community. "There are so many collection systems--for imagery, signals intelligence, etc.--that being able to present diverse information in a coherent way is an enormous engineering job," said Don Bently, program manager at BAE Systems.
A shift to open architectures in computer systems, he said, "should be a major step toward resolving interoperability problems." BAE Systems makes the so-called precision-targeting workstation for the U.S. Navy.
The Defense Science Board also recommended that the Pentagon accelerate the development of a modular advanced electronically-scanned-array radar with ground moving target indicator (GMTI). Wright said that the panel urged the Defense Department to spend more money on new systems such as foliage penetration (FOPEN radar and precision signals intelligence (SIC-NT) to be used for targeting. A combination of GMTI and FOPEN technologies, she said could be used to create a "GMTI sentry" that would survey enemy strongholds and "effectively engage [targets] as they emerge from hiding."
The problems highlighted in the DSB study were seen in real-world operation over Afghanistan (against the ruling Taliban regime) in October, when errant bomb killed and injured civilians who were not the intended U.S. targets. In one instance, Navy F/A-18 Hornet dropped a 1,000-pound, laser-guided bomb on a warehouse used by the International Committee of the Red Cross in northern Kabul. The Pentagon said that was an unintentional strike, which apparently had been aimed at the Kabul air port, a couple of kilometers away. Marine Corps Lt. Gen. Gregory S. Newbold, the Joint Staff's director of operations, told reporter that the number of missed targets was "minuscule," in the context of the air was overall. Over a three-week span in October the United States and allies launched more than 3,000 bombs and missiles against tar gets in Afghanistan.
During one weekend in mid-October, a least three U.S. bombs were reported to hit civilian sites, unintentionally. A Navy F-14 dropped two 500-pound bombs on a residential area near Kabul. According to Pentagon officials, the fighter had been aiming at enemy vehicles parked less than mile away. In a separate strike mission, an F/A-18 was aiming at a Taliban storage facility but instead struck a field in the vicinity o a home for the elderly.
Defense Secretary Donald Rumsfeld said that incidents of misfires, regardless of whether they are caused by equipment failure or human error, should be accepted as realities of war.
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|Title Annotation:||Joint Direct Attack Munition|
|Author:||Erwin, Sandra I.|
|Date:||Dec 1, 2001|
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