US Marines' latest anti-drone toy is an AI turret that uses regular machine guns

The US military is adding autonomous gun-based counter-drone systems intended to reduce its reliance on expensive interceptor missiles.

Defense robotics firm Allen Control Systems (ACS) announced a deal with the US Marine Corps on Monday to get its Bullfrog autonomous weapon system attached to the Light Marine Air Defense Integrated System (L-MADIS) expeditionary counter-drone platform. L-MADIS consists of pairs of off-road vehicles, one carrying a suite of sensors and the other slated to be outfitted with a Bullfrog autonomous weapon station.

Bullfrog systems are a little different from your typical AI-controlled counter-drone systems in that they’re not built with an attached weapon, but are designed to slot in “any legacy or modern firearm” in order to turn them into systems able to “detect, track, and defeat incoming threats at a fraction of the cost of even the least expensive kinetic interceptors.”

In other words, ACS claims it's cheaper to build a system that can adapt existing military firearms than to invest in a purpose-built counter-drone weapon system. Bullfrog units provide the AI, computer vision, and precision aiming robotics to take out drones, while the military only has to plug in its own hardware.

There are several variants of the Bullfrog available from ACS, with units designed for everything from the M240 machine gun to the M2 50-caliber machine gun. The company is currently working on M230 chain gun and M134 minigun variants as well. In the case of the Marine Corps contract, it appears the service is taking on some M240 variants based on a link in ACS’s press release to the M240-variant’s page.

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The M240, the smallest of the weapons designed for the Bullfrog, fires up to 850 7.62×51 mm NATO rounds per minute and is effective up to 800 meters in the Bullfrog. The Bullfrog M240 is capable of taking down drones up to DoD Group 3, meaning anything with a max gross takeoff weight less than 1,320 lbs, able to operate as high as 18,000 feet above sea level, and with an airspeed of less than 250 knots. The DoD grouping goes up to Group 5, which includes some of the military's largest drones, such as the RQ-4 Global Hawk.

The US Army and US Navy are both already fielding Bullfrog units, making the Marines the third branch to get their hands on the system. ACS cited the proliferation of cheap drones in the Russia/Ukraine conflict and in the Middle East as a need for comparable cheap counter drone tech.

Videos on ACS’ YouTube page demonstrate the Bullfrog in action, taking down a number of small drones in demonstrations over the past couple of years. A short video on the company's channel also shows a Bullfrog unit switching from targeting aerial drones to ground targets with ease. This suggests that Bullfrog systems aren't just capable of knocking drones out of the sky.

After we published this article, ACS has been in touch to explain that, despite what the video showing Bullfrog switching from aerial to ground targets on demand, it's not correct to say it autonomously targets humans.

"Bullfrog has robust software protections against the fully autonomous engagement of designated targets, including human combatants," an ACS representative told us.

The company went on to explain that, while Bullfrog can target humans, it doesn't do so without human operator oversight.

"Bullfrog is designed to operate under accepted rules of engagement and laws of war. The computer doesn’t decide what to do — humans do," the spokesperson told us.®

Updated on July 22 with comment from ACS about autonomous targeting.