Simi Valley defense firm develops artillery shield.

The "proximity fuse" is a nasty and ubiquitous piece of modern weaponry, but a Simi Valley company has come up with a way to essentially make it harmless.

Built into better than 80 percent of artillery and mortar shells, the proximity fuse is essentially a miniature radar system that detects when a shell is a dozen or so feet above target, and then detonates its explosive.

The effect is a wider radius of shrapnel damage than even a direct hit would inflict. Impact-detonated shells send much of their shrapnel straight into the ground.

Now Simi Valley-based Whittaker Corp. says it has a portable device that, according to Army testing, can thwart nearly any proximity-fuse shell by using the weapon's own radar against it.

The $100,000-plus Shortstop Electronic Protection System is a new version of a product first deployed in Saudi Arabia in the aftermath of the Gulf War. The Army had hoped to deploy it during the war, but the conflict ended too soon.

Testing has been completed on the new version of Shortstop at the Army's Yuma Proving Ground in Arizona, where it successfully detonated prematurely each of 5,000 live artillery and mortar rounds fired at it individually and in barrages, according to Army officials.

Based on the device's promise, Congress has added $5 million to the Army budget to buy 20 of the systems, and is considering funding 20 more next year.

That kind of contract would be a boon to Whittaker, which is looking to get out of defense electronics manufacturing by selling the very division that produced the device.

"Shortstop is one of the most exciting programs we have and one of the most visible," said James Schultz, Whittaker vice president for business development. As such, it could help attract potential bidders for ali or select parts of the company's electronic systems division, Schultz said.

The Army, for its part, is anxious to deploy Shortstop systems in South Korea, where U.S. soldiers are stationed near the demilitarized zone separating north and south. That area is expected to see heavy shelling in the event of a conflict.

U.S. soldiers deployed in Bosnia last year also took along a handful of the devices for field testing, though the Army would not comment on whether the systems were ever needed, or how well they performed.

But weapons analyst Joe Langevin, founder and CEO of Tracer Round Associates in Alexandria, Va., said Shortstop is an auspicious product.

"I think it's good," Langevin said. "I think it's very, very good."

While early models weighed in at nearly 200 pounds, and cost $30 million to develop, three newer versions are all lighter and cheaper. They include a vehicle-mounted Shortstop, one that rests on a tripod, and a 25-pound model that a soldier can carry in a backpack.

Schultz said Whittaker expects to get production costs for the devices down to around $60,000 apiece.

Though of varying sizes and ranges, all three of the Shortstop models function essentially the same way: The device's antenna passively detects radar signals from incoming shells. (Those signals tell the shell how far above the ground it is.)

Shortstop next fires a burst of radio signals at the shell, rotating through thousands of frequencies until one is found that the shell responds to. Shortstop then "lies" to the shell, telling it has reached its target altitude, causing the shell to detonate - ideally hundreds of meters prematurely.

Shortstop has no effect on shells that detonate on impact.

Beyond battlefield situations, Schultz said, Shortstop could be used to protect embassies, airports or even corporate headquarters; any area, in other words, that might attract terrorist shelling.

Indeed, Tracer Round's Langevin said commercial applications could eventually generate as much business for the Shortstop technology as military purchasers. So far, however, Whittaker is only allowed to sell the technology to the militaries of the so-called ABC countries - Australia, Britain and Canada.

With such a potentially lucrative market for Shortstop, why is Whittaker looking to sell its electronics division?

Size, says Schultz.

With ongoing consolidation in the defense industry, a company the size of Whittaker, with 900 employees and annual revenues in the $150 million range, can hardly compete with behemoths like GM Hughes Electronics Corp., McDonnell-Douglas Corp. and Boeing Co., he said.

"We don't believe that long-term, alone, that defense unit will have much (chance)," he said.