Animals

Peregrine Falcon Attack Strategies Could be Used to Down Rogue Drones

Oxford University researchers plan to replicate the bird of prey's attack strategy. Friday, 8 December 2017

By Jonathan Manning
A peregrine falcon patrols the sky above Manchester.

The dramatic stoop of the peregrine falcon in attack mode uses the same control strategies as guided missiles to hit its prey, researchers at Oxford University have discovered.

Their findings contradict previous assumptions that the world’s fastest animal follows simple geometric rules when ambushing its targets.

The research was initially funded by the US Air Force Research Laboratory and could be applied to the design of small, visually guided drones that can take down other ‘rogue’ drones in settings such as airports or prisons.

The peregrine falcon is the fastest bird on the planet, capable of reaching speeds of 200mph when it dives to attack prey.

The Oxford researchers spent four field seasons flying falcons in the Welsh hills, working with an experienced falconer and a qualified drone pilot as part of their study. They attached miniature GPS receivers to track the raptors as they attacked dummy targets thrown by the falconer or towed by a drone. The scientists then applied a mathematical simulation to these movements to model the dynamics of the bird of prey’s guidance system used to intercept its next meal.

Principal investigator Professor Graham Taylor, of the Oxford Flight Group in Oxford University’s Department of Zoology, said: ‘Falcons are classic aerial predators, synonymous with agility and speed. Our GPS tracks and on-board videos show how peregrine falcons intercept moving targets that don’t want to be caught. Remarkably, it turns out that they do this in a similar way to most guided missiles.”

The findings are published in the journal PNAS, and may also give scientists greater insight into the pursuit behaviours of other predatory species, whether in the air, in water, or on the ground.

On-board video gave a falcon’s-eye view of the attacks and reinforced the researchers’ conclusions. They discovered that the terminal attack trajectories of peregrines follow the same law – known as proportional navigation (PN) – used by visually guided missiles, but with a tuning appropriate to their lower flight speed. This method does not require any information on a target’s speed or distance, but instead relies simply on information about the rotation of the attacker’s line of sight to the target.

Recent publicity has revealed the growing problem of drones flying drugs and mobile phones into prisons, and of drones being flown in the vicinity of airports, and the researchers suggest that PN guidance optimised for low flight speeds could be a practical solution for small, visually guided drones designed to take out other drones from protected airspace.

Co-author Dr Caroline Brighton, from Oxford’s Department of Zoology, said, “It was very exciting to study these sleek, formidable aerial predators, and to watch them as they chased down our manoeuvring lure towed behind a small remote-controlled airplane – then, through our computer modelling, to reveal the secret of their attack strategy.”

The ultimate airborne hunter could soon be 'teaching' drones how to take down other rogue drones.
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