How the Army Plans to Counter and Destroy Enemy Drone Swarms
February 19, 2020 Topic: Technology Region: Americas Blog Brand: The Buzz Tags: SwarmU.S. ArmyArmyMilitaryTechnologyWorld

How the Army Plans to Counter and Destroy Enemy Drone Swarms

Will it work?

Key point: Missile and drone swarms are a real threat because they overwhelm anti-air defenses. The military knows this and wants to find a way to shut them down.

A drone and cruise missile attack that occurred on Saudi oil facilities in August 2019 revealed just how important short-range air defenses are becoming for defense against cruise missiles and drones that are proliferating across the globe.

Existing air defense batteries like the Patriot missile or THAADs have been optimized to defeat high-flying jet fighters and ballistic missiles. 

Drones and cruise missiles are fairly small and can skim close to the ground. That makes them relatively difficult to detect on radar, meaning they may only be detected once they are fairly close to their targets. And that’s where short-range defense can provide protection and a final layer of defense, like a goalie in a soccer team.

In a recent article, I highlighted that the Army is moving rapidly to acquire Stryker mobile air defense vehicles, and Israeli Iron Dome batteries for more static defense roles to fill in this increasingly dangerous gap in its air defense capabilities.

However, a colleague of mine in the Air Force challenged me: what specific capabilities did the new Stryker anti-aircraft vehicle possess would perform so much better against drone swarm attack? 

After all, the Saudi had deployed radar-assisted 35-millimeter flak cannons and Shahine self-propelled anti-aircraft systems (basically Crotale missiles plopped on top of a French AMX-30 tank)  already deployed at the sight didn’t have?

If this sounds like another near-religious invocation of the Air Force’s classic mantra “The bomber will always get through,” it is, sort of. 

But this time it’s rather that “the drone swarm will always get through.”

Large numbers of missiles or drones can overwhelm air defenses with little concern. Not only are many existing air defense systems incapable of dealing with numerous targets fast enough, but their individual missiles costing tens of thousands of dollars may be to expensive and limited in number to expend in the volumes necessary to clear the skies of cheaper types of drones in particular.

Currently, the U.S. Army’s only mobile SHORADS system is the AN/TWQ-1 Avenger, a Humvee mounting two four-shot missile pods on its back loaded with FIM-92 heat-seeking Stinger missiles.  It has a fast-firing .50-caliber M3 machinegun as a backup weapon.

The Avenger uses a forward-looking infrared sensor and a laser-range finder, but doesn’t have an organic radar to peer further over the horizon.  Instead, it can use tracking data networked from an external radar vehicle.

This Avenger doesn’t compare all that favorably with Russia’s specialized tracked Tor missile system or its Pantsir-S1 air defense vehicle.  The latter truck-mounted system has an organic radar that can spot targets up to 20 miles away, backup infrared sensors, command-guided missiles with three or four times the Stinger’s range, and two super rapid-firing 35-millimeter cannons. 

The disparity in performance reflects that Russia worries a lot more about being attacked from the air, while the U.S. Army has trusted the Air Force to take care of aerial threats since the end of the Cold War.

But the drone and cruise missile threat emerging even from lower-capability adversaries like ISIS or Iran is proving that assumption to be outdated.

What does the Stryker Bring to the Table?

In 2018, the Army revealed its initial solution for mobile short-range air defense would come in the form of a modified Stryker armored vehicle.

The Stryker is an eight-wheeled armored personnel carrier is intended for deployment in medium- to low-intensity conflict areas. The basic M1126 infantry carrier models weighs eighteen tons, is protected against heavy-machine gunfire and comes in numerous variants support-role variants.

The M-SHORAD Stryker’s armor protection is already an important leap up from the soft-skinned Avenger.  While the Stryker isn’t built to withstand proper anti-tank weapons, it can brush off machinegun fire and or light artillery fragments that are more common battlefield threats. That, in turn, means it can accompany U.S. mechanized units into more dangerous combat situations.

The M-SHORAD Stryker features a new turret called the Reconfigurable Integrated weapons Platform (RIwP, a rather awkward acroyn) combining four weapons: a 30-millimeter M230F(L) automatic cannon, Stinger missiles like on the Avenger, heavier Hellfire missiles, and a 7.62-millimeter machinegun.

This unconventional package os seemingly calculated to remain effective against enemy armored vehicles as well as attack helicopters, drones, missiles and low-flying jets.

The AGM-114 Hellfire is generally thought of as a laser-guided tank-busting missiles. However, the AGM-114L model of the Hellfire, which uses a millimeter-wave radar seeker, might prove appropriate for engaging airborne targets.

The Hellfire’s most obvious draws compared to the Stinger, however, is that it has twice-range at five miles, and hits much heavier with its shaped-charge warhead. However, the crew of the SHORAD Stryker will have to exit the turret to reload the two-shot Hellfire pod.

One pod mounts four Stinger missiles which can be reloaded inside the vehicle. The Stinger has a range of 3 miles and uses a dual infrared/ultraviolet seeker, and downed numerous Soviet aircraft in the 1980s when transferred by the U.S. to Afghan insurgents. 

Recently, the U.S. began procuring new Stinger model with a proximity warhead intended to increase its odds of knocking down drones, as dramatically illustrated in this test video.

The 30-millimeter M230LF chain gun—like the Hellfire, armament more traditionally found on the Apache attack helicopter—could also engage more distant targets with its air-bursting shells that can be discharged at a rate of over three rounds per second. 

The M230 has a maximum range of 2.5 miles away, though its accurate range may be closer to one mile. However, depending on how the M-SHORAD Stryker’s turret is configured, it may not be able to elevate the gun high enough to shoot at closer, higher-flying targets.  A superficial examination of the proposed SHORAD turret suggests it may not be able to elevate more than perhaps 60-70 degrees, though there may be additional accommodations to exceed that.

For self-defense and flexibility for engaging easier, lower-urgency targets, the M-SHORAD Stryker also retains a light 7.62-millimeter machinegun.

Sensors and Electronic Warfare

Unlike the Avenger, each Stryker M-SHORAD will have its own organic radar built by Radar capable of providing 360 degree coverage to track, identify and engage both air and ground targets.  This means that individual Strykers won’t depend on the presence of external radars like the Avenger.  And if they are networked with additional radars, they might actually contribute to expanding the collective radar coverage.

Though the radar likely exceeds the range of the Stryker’s weapon, it will allow the crew better situational awareness and cue their weapons once the hostiles enter within range.

The U.S. Army has also combat-tested anti-drone jammers that disrupt the signals remote-controlling them—causing drones to literally fall out of the sky for lack of input.  In one Syrian drone attack on a Russian airbase, seven of thirteen drones shot down were disabled by such attacks.  Therefore, the electronic warfare system may end up proving at least as valuable as the Stryker’s more obvious weapons.

The M-SHORAD Stryker is due to debut in an Army exhibition later this October. The Army plans to receive 144 SHORAD Strykers—the first twelve-vehicle batteries entering operational service in 2020, with four battalions planned by 2022.

Northrop Grumman is separately developing a SHORAD variant armed with a 50-kilowatt laser designed to burn drones out of the sky.  That may be more cost-effective versus inexpensive drones, though performance may be impaired by inclement weather.

Overall, while the Army has been understandably tight-lipped about the exact performance parameters of its forthcoming new air defense vehicles, it seems to boast improved capability to detect incoming threats and engage them with a variety of weapon systems.  Whether it can do so well enough against new threats posed by drones and cruise missiles remains to be seen.

Sébastien Roblin holds a Master’s Degree in Conflict Resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing, and refugee resettlement in France and the United States. He currently writes on security and military history for War Is Boring. This first appeared in 2019.

Image: Reuters