Metal Detecting from the Air

Recall a DOD project looking a a related problem.   Hope this does not become an issue in greater Europe.

Metal-Detecting Drone Could Autonomously Find Land Mines A drone with 5 degrees of freedom can safely detect buried objects from the air.  By Evan Ackerman 

Several stitched-together photographs of gray three-propellered drones with metal detectors hovering just above grass

This composite photo shows how a tricopter drone with a lidar and metal detector can fly around an obstacle close to the ground.

Metal detecting can be a fun hobby, or it can be a task to be completed in deadly earnest—if the buried treasure you’re searching for includes land mines and explosive remnants of war. This is an enormous, dangerous problem: Something like 12,000 square kilometers worldwide are essentially useless and uninhabitable because of the threat of buried explosives, and thousands and thousands of people are injured or killed every year.

While there are many different ways of detecting mines and explosives, none of them are particularly quick or easy. For obvious reasons, sending a human out into a minefield with a metal detector is not the safest way of doing things. So, instead, people send anything else that they possibly can, from machines that can smash through minefields with brute force to well-trained rats that take a more passive approach by sniffing out explosive chemicals.

Because the majority of mines are triggered by pressure or direct proximity, it may seem that a drone would be the ideal way to detect them nonexplosively. However, unless you’re only detecting over a perfectly flat surface (and perhaps not even then) your detector won’t be positioned ideally most of the time, and you might miss something, which is not a viable option for mine detection.

But now a novel combination of a metal detector and a drone with 5 degrees of freedom is under development at the Autonomous Systems Lab at ETH Zurich. It may provide a viable solution to remote land-mine detection, by using careful sensing and localization along with some twisting motors to keep the detector reliably close to the ground.  ...'