The silent sentinel

Always on guard: Radars are the first line of a strong defense

A radar, a highly advanced type of sensor, is patient. It’s always on, searching and detecting. It's quiet until needed.

“Sensors aren’t sexy,” said Cliff Johnson, a director for business development in tactical radars at Raytheon.

Yet radars help military operators distinguish between friend or foe. Without it, they might as well be using binoculars.

To detect and identify an airborne object, a radar relies on its command and control, the brains of the system. The information it collects alerts those it defends to possible danger and helps them decide how to deal with it.

“If the data shows it’s hostile, then the brain looks for a way to engage and defend,” Johnson said.

Two multi-function radars, Raytheon’s KuRFS and Sentinel, maintain high-fidelity tracks on targets even as they search for new targets.

KuRFS, or the Ku-band Radio Frequency System, is a 360-degree radar that cues defensive weapons. It can be set up within 30 minutes, either in a fixed location or on a vehicle.

Raytheon built the KuRFS multi-mission radar to help the U.S. Army defend against rocket, artillery and mortar attacks in Iraq and Afghanistan. Today, it is also used as a counter-drone radar. It works with multiple weapons systems, including the land-based Phalanx Weapon System, 50-caliber guns, 30mm cannons and the Coyote unmanned aircraft system.

“Both KuRFS and Sentinel are eyes in the sky,” Johnson said.

Sentinel, technically known as AN/MPQ-64, is a radar that alerts front-line, air-defense weapons to hostile planes, helicopters, drones or missiles. It has three-dimensional coverage, reporting the range, bearing and elevation of the objects it is tracking.

With more than 300 systems deployed around the world, the Sentinel radar is relied upon for short-range to medium-range detection.

Watching the drones

Both radars can detect low-flying, small, slow drones, Johnson said. That specific mission helps to close the threat gap that other sensors might miss.

“With the smaller drones, operators have less to detect due to smaller wing, motor and engine sizes, and they fly slower that many radars are tuned for,” he said.

Engagement is the endgame, according to Johnson.

Raytheon’s directed energy systems work with radar to identify and track incoming drones. The high-energy laser system, or HEL, uses  beams of focused light to take down small, fast-moving targets like drones or mortars.

“One of the unique things about the high-energy laser is that because it moves at the speed of light, it can (very quickly) take a drone down,” said Michael Hofle, HEL product line lead at Raytheon Space and Airborne Systems.

When swarms of drones attack, ground troops can use a high-power microwave that emits an adjustable energy beam to disrupt and down unmanned aircraft systems. There is also the Stinger missile, which is now equipped with a proximity fuse that allows it to destroy drones by detonating near them.

All of these engagement options depend on a capable radar.

“If you don’t have the ability to see the target, you minimize the ability to engage the targets,” he said.