Throughout history, humans have employed falcons as lethal hunters of other animals. Now those raptors are being sent after drones.
It turns out that many of the skills feathered predators use to find a tasty lunch can be applied to the developing field of drone defense. A U.S. Air Force-funded study by zoology researchers at Oxford University suggests that the means by which a peregrine falcon tracks its quarry could be effective in defending against drones that threaten troops, police or airports.
The researchers fitted the falcons with miniature video cameras and GPS receivers to track their angle and method of attack on other birds, or on bait being towed through the air by a drone. In a paper published Monday in the Proceedings of the National Academy of Sciences of the U.S., the falcons' approach to intercepting its target aligned closely with the rules of proportional navigation, a guidance system used by visually-directed missiles.
The principle is such that a missile—or a falcon on the hunt—will reach a target as long as its line-of-sight remains unobstructed while it closes in. The earliest AIM-9 Sidewinder heat-seeking missiles, dating to the 1950s, used this technique with a rotating mirror to "see" the target.
A key difference, however, is that falcons adjust their angle of attack to compensate for their slower speeds—which is where drones come in. The work, the researchers suggested, could be applied to the development of small, visually-guided drones that can disable other drones.
"We think that the finer details of how peregrines operate could certainly find application in small drones designed to remove other drones from protected airspace," Professor Graham Taylor, the principal investigator, wrote in an email. The research involved data from 55 attack flights in Wales with falconers and a certified drone operator.