U.S. Army presses ahead on precision-guided artillery.

To help fill the void caused by cancellation of the Crusader artillery system, the U.S. Army is speeding up development of the Excalibur XM-982 family of precision-guided munitions.

Excalibur--named for the sword of Britain's mythical King Arthur--will be the Army's first artillery projectile guided by a global positioning system, according to the prime contractor, Raytheon Missile Systems, of Tucson, Ariz. It is similar to the Extended Range Guided Munition (ERGM) and Long Range Land Attack Projectile (LRAP), which also are being developed by Raytheon.

The ERGM will be fired by the Navy's new 5-inch, 62-caliber Mod 4 gun, now being installed on Arleigh Burke-class destroyers. The LRAP is planned for the 155 mm Advanced Gun System, which United Defense, L.P., of Arlington, Va., is developing for the Navy's DD-X family of future surface-combat ships.

Excalibur will be a family of modular projectiles with three distinct payloads. A unitary warhead will be used against personnel, equipment and building targets in urban or complex terrain. A sensor-fuzed munition variant will engage self-propelled artillery and armored vehicles. A dual-purpose, improved conventional-munitions version will be employed against personnel, materiel and light armor.

The concept is considered a technological breakthrough for the Army, said Lt. Col. Jeffrey K Wilson. He is Excalibur's product manager in the Army's Armaments Research, Development and Engineering Center (ARDEC) at Picatinny Arsenal, N.J. "With Excalibur, we can take on missions that field artillery could never rake on before," he told National Defense.

Range and Accuracy

As envisioned, he said, Excalibur would extend the range and accuracy of existing artillery weapons, such as the Paladin M-109A6 155 mm self-propelled howitzer and two towed cannon, the British-made XM-777 lightweight 155 mm howitzer and the heavier, 20-year-old M-198 155 gun. Current U.S. howitzers are outgunned by those used by potential adversaries, such as Iraq and North Korea, according to Army officials.

Although Excalibur is being designed to be fired by 155 mm howitzers, versions also could be developed for the Mobile Gun System, which is part of the Army's new Stryker family of light armored vehicles, and the Future Combat System, which is scheduled to be fielded in 2010, Wilson said.

"It's just a matter of exporting the technology to a smaller caliber," he explained. The MGS--the first of which was delivered to the Army in July--carries a 105-mm gun. Designers are considering either a 105 or 120 mm weapon for the FCS.

In August, the Army awarded a $27 million contract to United Defense, which lost the Crusader job, calling for the firm to begin designing a cannon system for the FCS. The new contract was for the remainder of fiscal year 2002.

The House and Senate, in their respective appropriations bills, agreed to provide another $368.5 million in fiscal year 2003 for the FCS cannon project. At press time, however, the two houses had yet to agree upon a single bill for the president to sign into law.

Crusader was intended to be an automatic-loading, self-propelled 155 mm howitzer. It was supposed to replace the 40-year-old, manual-loading M-109 series of cannons, which includes the Paladin, also made by United Defense. The Bush administration, however, cancelled the $11 billion program, saying that the 40-ton Crusader was too heavy for rapid deployment.

Excalibur is intended to improve the performance of existing artillery systems and to be compatible with future ones, explained retired Army Col. Frank Hartline, a business-development manager for Raytheon. It works like this: A cannon fires the munition high into the air, where it receives target-location data from GPS. Then, it deploys its wings and flies to the target, guided by an inertial navigation system equipped with anti-jamming technology.

Excalibur can destroy targets in first-round fire from ranges up to 30 miles, Hartline noted. It could extend the range of the Palladin, for example, by up to 30 percent, he said.

Also, Hartline said, Excalibur offers improved accuracy Excalibur is an extremely precise munition,' he said. It can hit within a circle of 10 to 20 meters, as opposed to 370 for traditional shells, he said. If you can do that, "you can be very lethal. You can have one-shot kills."

Increased accuracy means less collateral damage, Hartline said. "We've been fighting in a lot of places with civilian populations," he said. In Afghanistan, he noted, air strikes sometimes have hit civilians apparently in error. "Excalibur can hit the bad guys with less chance of killing civilians," Hartline said.

More accurate fire also can mean fewer casualties among U.S. and allied troops. In the Gulf War a decade ago, so-called friendly fire caused 17 percent of all U.S. casualties. Several such incidents also have occurred in Afghanistan.

Of course, precision guidance doesn't help if you use incorrect coordinates or choose the wrong target altogether, Wilson said. Using a relatively small artillery shell, however, can cause less damage than a major air strike, he said. "If you drop a 5,000-pound bomb, it's going to take our a much larger area."

Also, Hartline said, increased accuracy means that it will take fewer munitions to kill a target. "Excalibur will reduce the logistics burden by 30 to 40 times," he said.

Carrying fewer rounds, the weapon's crew will be able to fire, hit the target and move on--an artillery tactic known as "shoot and scoot"--much more quickly, Hartline explained. This will enhance the crews survivability by making it "much less likely for them to be fired upon themselves," he said.

Lightening the load also might make it easier to deploy artillery pieces, Hartline said. U.S. commanders cited logistical concerns as among the reasons for not deploying artillery in Afghanistan's rugged terrain.

Individual Excalibur rounds, however, certainly will not be light, Wilson said. Weighing 106 pounds apiece, they wilt have to he loaded manually to he fired from current artillery pieces, he noted. "It's definitely a two-man lift," he said.

Excalibur is being developed by a team that includes--in addition to Raytheon and ARDEC--General Dynamics Ordnance & Tactical Systems, of St. Petersburg, Fla.; L-3 Communications, of Redmond, Wash.; Eagle-Picher Technologies, of Joplin, Mo.; Alliant Techsystems, of Minneapolis; Micro Pulse, of Camarillo, Calif., and the Army Research Laboratory, in Adelphi, Md.

The program began in 1998 as part of the Pentagon's effort to develop precision-guided munitions that can be fired from Army and Navy artillery pieces. Precision-guidance systems have been used in missiles and bombs for years, Hartline said.

Those munitions, however, subject their guidance systems to considerably less stress than artillery, he said. The bombs simply are dropped into the air, and the missiles rise slowly from their launch pads, gradually building speed. But artillery is something else, Hartline said.

"The biggest challenge for cannon-launched, precision-guided munitions has been getting that sensitive guidance technology safely out of the very difficult environment of a gun barrel," Hartline explained. When a cannon is fired, it can release a force equal to 15,500 G's or more. "That has a huge impact on anything inside the barrel," he said. That is especially true of sensitive precision-guidance equipment, he noted.

In May of this year, the Excalibur ream successfully fired a precision-guided projectile equipped with a complete Inertial Measurement Unit at the maximum permissible launch acceleration.

Tests at Yuma

The test--which took place at the Army's Yuma Proving Grounds in Arizona--was significant, because "it confirmed that new cushioning material and structural anchoring designs can withstand forces beyond the maximum permissible pressures experienced in the gun environment," said David Martin, Raytheon's vice president for guided projectiles.

The tests at Yuma used multiple cameras, radar and on-board sensors to record stability, structural integrity and flight characteristics of the projectile. Tests were performed at minimum and maximum charge zones, including five percent over maximum operational gun pressures, producing velocities up to 850 meters per second from the 39-caliber cannon.

The ERGM and LRAP programs, which use similar technology, also have completed several successful tests in the past two years.

Over the next one to two years, the Excalibur team plans to test fire frill rounds, Wilson said.

The team had planned to field Excalibur in 2008, he said. But Michael Wynne, principal undersecretary of defense, technology and logistics, has said he wants fielding to take place in 2006.

Some experts have questioned the wisdom of speeding up development of Excalibur's new and relatively untested technologies. Such an acceleration would be "a recipe for failure," warned Phil Coyle, the Pentagon's former director of operational test and evaluation, who is now an advisor for the Center for Defense Information, a Washington, D.C.-based think-tank. "Why shouldn't the Army be given the time for a real, no-kidding analysis of alternatives?"

Both Wynne and Hartline, however, argue that early fielding is achievable. In fact, Hartline said, "we think it could be done in 2005 if the Army wants to get it out that soon.

In an effort to speed up development, the Bush Administration is increasing spending on the project. Through fiscal year 2001, the Excalibur program spent $60 million, according to Chris J. Grassanoo, Excalibur's deputy product manager. The 2002 budget was $61.2 million, he said.

For 2003, the administration has proposed reallocating $48.3 million from the defunct Crusader program to Excalibur, increasing the yearly total for the new munition system to $119.2 million, Grassano said.

Like all precision-guided munitions, individual Excalibur rounds will not be cheap. In a report accompanying on the 2003 defense bill, two Democrats on the House Appropriations Committee--Reps. Norm Dicks, of Washington state, and Chet Edwards, of Texas--estimated that it would cost about $222,000 per round, or $2.1 billion for the first 9,417 Excalibur projectiles.

Grassano presented a much lower figure. "While the unit cost varies significantly with quantity, current conservative estimates indicate an average per-unit cost of $35,000 for 105,000 projectiles," he said.

Further complicating Excalibur's development is the Army's decision last year to merge it with a similar project, the Trajectory Correctable Munition (TCM). Like Excalibur, TCM was intended to become an extended-range, precision-guided 155 mm projectile. It was a joint project involving the U.S. and Swedish armies; Science and Applied Technology Inc., of Woodland Hills, Calif., and Bofors Defence, a Swedish subsidiary of United Defense. Congress in 1999 directed the Pentagon to pursue the TCM concept with the Swedes. TCM was making progress. In February 2001, Bofors successfully tested deployment of TCM fins at high speed. But the Army decided last year that it couldn't afford to fund two programs that are so similar,

Instead, it is combining the best elements of the two programs--Excalibur's guidance and control element and TCM's airframe and folding fins-into one system, Grassano explained. In May, the Army selected a new, single design for the combined munition. A contract for the next stage is scheduled to be awarded later this month, he said.

The merger "has a lot of advantages," Hartline said. It "has a lot of problems too," but none that are not solvable, he said. One attractive aspect of the merger from the U.S. standpoint, he said, is that the Swedish army is investing $54 million in the program.

In any case, Hartline said, it is important that artillery get a precision-guided munition of some kind. "Some of us believe that, if cannon artillery doesn't make that transition, its role will be limited in the future."

With precision-guidance, Wilson said, artillery will remain "the quickest way to get steel on tar get."