Small drones are a growing battlefield threat. Some are garage-built projects, others simply commercial quadcopters modified to drop grenades. They can do tremendous damage – as the attack which knocked out the Abqaiq oil processing plant last year showed – and proved frustratingly difficult to shoot down with small arms when used by ISIS in Mosul.
Raytheon are the premier makers of surface to air missiles for the U.S. military, producing everything from long-range Patriots to shoulder-launched Stingers. But when it comes to tackling swarms of $2,000 drones, a new approach was needed. In 2018 the U.S. military deployed Raytheon’s Coyote for drone defense. This is a tube-launched interceptor, driven by an electric propeller and cruising at 60 mph which destroys targets with an explosive warhead.
The new Coyote 2 is a dramatic upgrade. After a high-speed, rocket-boosted launch, a miniature jet turbine cuts in. This makes it much faster than the original Coyote – Raytheon will not say just how fast — and more maneuverable than a missile.
“We’ve leveraged commercial, off-the-shelf components to design a low-cost interceptor driving down the cost exchange ratio,” says project manager Abel Ghanooni. In other words, unlike a typical surface-to-air missile it is cheap enough to be used against large numbers of incoming drones.
The Coyote 2’s agility is provided by four small control surfaces which pop out around the tail, resembling the fins of a rocket. These allow it to slew around at high speed and pursue difficult targets.
“It has dogfight-type of capability,” says James McGovern, Raytheon VP of mission systems and sensors. “With a turbine engine, it has controllable thrust throughout the entire engagement, allowing it to close in on small targets that may be evading or jinking.”
Tests with an inert warhead showed that the interceptor is accurate enough to physically impact the target, hard enough to punch through (see 0:17 in video above). However, it does not need to get that close. While surface-to-air missile warheads are designed to damage larger aircraft, Coyote 2’s warhead has been engineered to produce a ‘fragment field’ of small, fast-moving shrapnel optimized to take out small drones.
The interceptor is linked to mobile radar on the ground, known as KuRFS. Unlike most radar, this is specially designed to spot, locate, and track small targets at long range using multiple small antennas. The radar is sensitive enough to pick up incoming mortars and rockets, as well as drones. The radar passes target data to the Coyote 2, so the interceptor itself does not require sophisticated onboard sensors. The combination is like a rifle with expensive sights but firing cheap ammunition, a useful capability for dealing with swarms of small drones.
McGovern says the idea is to have a layered defensive system, with the interceptors doing the work at long range and guns, missiles – or in future lasers or microwave weapons (which Raytheon is also developing) – taking on the rest. The basic system carries four Coyote 2s ready to launch, but more launchers can be added to the system as needed.
“You want to engage as many targets as you can at longer range so what you get at short range is a few leakers, not the whole swarm,” says McGovern.
Coyote 2 has entered service with the U.S. military and Raytheon are now offering it to international customers. The attack on Abqaiq, and mass drone assaults on the Russian airbase at Khmeimim in Syria, show how easily swarms of drones can be deployed even by non-state actors. Such attacks can rapidly deplete stocks of expensive missiles, or overwhelm them. Any drones that get through can attack with lethal effects.
In future conflicts, drone swarm versus interceptors is likely to become an increasingly key battle. Whoever has the fastest, most agile, and most numerous drones is likely to come out the winner. Coyote 2 may help defenders stay ahead of the threat.