Program to Introduce New Threat Detection, Countermeasure Capabilities

By Donna Miles
American Forces Press Service

April 27, 2009 - A lot of questions are likely to rush through your head when you're out on the battlefield and the enemy projectiles come flying. The Defense Advanced Research Project Agency is making big strides on a program to respond with life-saving speed and accuracy. The goal of DARPA's CROSSHAIRS – or Counter Rocket-Propelled Grenade and Shooter System with Highly Accurate Immediate Responses -- program is to develop a threat detection and countermeasure system for light tactical vehicles, program manager Karen Wood explained.

As envisioned, Wood said, CROSSHAIRS will be able to detect and locate enemy shooters firing threats ranging from bullets to rocket-propelled grenades to anti-tank guided missiles to direct-fired mortars. In addition, it will engage the shooters and notify other friendly forces of the threat.

"In an engagement, what am I worried about?" Wood asked. "The first thing I have got to know is what is coming at me. So the CROSSHAIRS system has to be able to identify the threat coming in."

Next, Wood said, "I need to know, 'Is it going to hit me or not?' So CROSSHAIRS has to be able to track whatever is coming in."

"The third thing you want is to know where that shooter is so you can retaliate or put down suppressive fire" or take some other action, she said. "Then lastly, if something like an RPG is coming in, can I have self-protection?" she asked. "Do I have an active protection system to help me with vehicle survivability?"

CROSSHAIRS aims to do all this, then share details about the attack and the enemy's precise location with other friendly forces.

"I can seamlessly network that information to other vehicles in my convoy and let them know there is a shooter here," Wood said. "That way, if I am busy with survivability, they can do the retaliatory fire or respond to the shooter."

The CROSSHAIRS program builds on another DARPA effort: the Boomerang II acoustic gunshot detection system. This vehicle-mounted anti-sniper system "listens" for a bullet's shockwave and muzzle blast and transmits the shooter's location to the vehicle crew – all in less than a second.

The Army ordered about 8,000 Boomerang systems, and about half of them already have been deployed to the combat theater, Wood said.

But test results during earlier stages of the CROSSHAIRS program determined that radars are the best way to detect larger projectiles. The contractor ultimately selected came up with a system Wood said was "head and shoulders above the rest" in successfully identifying the type and source of incoming fire.

The "Cross-Cue" sensor system combines low-cost radar and acoustics technology with signal processing.

The CROSSHAIRS system marries the two sensor technologies to respond to a full array of threats. "Now we have the Boomerang for gunshots and the Cross-Cue radar solution for everything else." Wood said.

The CROSSHAIRS program got a shot in the arm when the Army's Rapid Equipping Force agreed to team with DARPA to apply the technology to the Vanguard vehicle it was developing. In December, DARPA engineers took CROSSHAIRS' dual detection systems, along with its networking piece, and automatic weapon "slew-to-cue" capability and put the system through the paces at the Redstone Technical Test Center in northern Alabama.

"We don't make it easy for these contractors," Wood said. CROSSHAIRS had to stand up to gunshots, RPG rounds and machine-gun fire, all coming from different sources and often all at once. And as it responded, it simultaneously networked the information to another vehicle, which demonstrated an automatic weapon slew-to-cue to the shooter location based on the information received from the vehicle under fire.

Even Wood was surprised at the results. "The system really kind of hit a home run," she said. "Very rarely do you get to go before your director and say, 'We met all the objectives we were going after in this phase of the program.'"

The program, now in its final phase, then turned to developing an active protection system for CROSSHAIRS. The engineers faced two major challenges, Wood said. The system had to be affordable enough to deploy on light, tactical vehicles, and deployable in a way that didn't cause additional collateral damage.

"We are not gong to be spraying shrapnel or blowing something up at a distance, because innocents could get killed," she said.

After exploring numerous options, the DARPA team ultimately settled on another system their agency had initiated: the Iron Curtain. This system, mounted on the roof of a Humvee, defeats incoming projectiles using a shoot-down system to dud the round before it strikes the vehicle.

Because Iron Curtain shoots directly down from the rooftop and engages the incoming round just inches away from the vehicle, it causes little or no collateral damage, Wood said.

Wood explained how the integrated CROSSHAIRS system works. The radar detects and tracks the incoming round. An embedded optical sensor gives a profile of the round. "Based on a lot of shots, we know exactly where to hit that RPG to make it dud," she said.

Meanwhile, the vehicle crew is able to monitor the process, seamlessly networking the shooter's location and threat type to other friendly forces.

"It's quite amazing what we have done," Wood said of the system. "We are just marching on, developing these capabilities and hoping it is going to save soldiers' and Marines' lives."

If the program gets adopted by the services, as Wood said she fully expects, she said it will bring tremendous additional capabilities to warfighters.

"I've got the best job in the whole world," she said. "It's incredibly rewarding to have things go out that you know are going to protect our men and women."

With two nephews in the military, one who has seen combat in Iraq and a niece who will be deployed at the end of the year, Wood takes the mission personally.

"If there's anything I can do to help the warfighter, I'm all about it," she said. "It's very rewarding, and it's very satisfying."