Landmines have been used extensively in conflict zones throughout the world. Though wars may come to a close, subterranean landmines stay active and threaten to kill anyone who walks across the surface above the explosives. The HALO Trust estimates that fifty-eight countries, including Cambodia, Laos, Zimbabwe, and Afghanistan, have undetected landmines buried in the earth. Because landmines can remain active for decades, affected countries and humanitarian organizations have worked to increase and improve demining efforts.

Experts have employed ground-penetrating radar (GPR) in their efforts to safely locate and remove active landmines. Ground-penetrating radar offers a subsurface scan of the earth by sending small radio signals into the ground. Images, or “radargrams,” are created as the machine measures the time it takes underground structures to reflect the signal back to the scanner. Disturbances, called anomalies, in the wavelengths shown by the radargram indicate the presence of an underground structure. These scans offer a more comprehensive view of the earth’s subsurface than metal detection as GPR can sense and map non-metal objects.

Because landmines are set off when the ground above them is disturbed, demining comes along with considerable risks for workers. Most GPR systems have a stroller-like structure that a technician pushes across the ground. However, because an ordinary scanner cannot not be pushed over a potential minefield, researchers at the Tokyo Institute of Technology designed the Gryphon Humanitarian Demining Robot to combat this challenge.

The Gryphon makes use of both GPR and metal detection technology to identify and mark spots that may house an underground landmine. The machine has a body with four wheels that stays on safe ground while its crane-like arm extends over unsafe ground and scans without touching the surface. When a potential mine is detected, the Gryphon uses paint to mark the spot for further inspection. Because the arm and its sensors are remotely operated, workers stay on safe ground throughout the scan.

Since 2001, researchers have worked to test and improve the Gryphon system so that it may be integrated into global demining efforts, and thereby increase the safety of workers and citizens around the world.