17
Jun
2016

Non-cooperative soil – What is it? And why is it so important for landmine detection?

Speak to any of the scientists working on one of the landmine detection research projects Find A Better Way fund and within a few minutes you are bound to hear the term ‘non-cooperative soil.’

The term may sound a bit odd at first if you are not immersed in the world of demining, but non-cooperative soil is a major challenge for all landmine detection technologies. We thought we would take a moment to explain just what it is, why it is so important, and what Find A Better Way is doing to address the challenges it creates.

What is non-cooperative soil?

‘Non-cooperative soil’ is typically a mineral rich soil that causes interference with the readings from metal detectors, ground penetrating radar, and other detection devices.

When an electromagnetic waves penetrate the ground they can be corrupted by the magnetic properties of some minerals commonly present in soil, like iron or aluminium. You can experience a similar phenomenon if you listen to a radio station while driving under a bridge or inside a carpark.

Anything magnetic can distort the behaviour of energy waves, and most detection devices, old or new, rely on reading electromagnetic waves that pass through soil looking for buried landmines.

Another related issue is ground moisture as water boosts the conductivity of any soil. Poor drainage can result in massive interference for any detection device.

And, just to make matters more complicated, these two problems are often combined. Laterite a soil type that has a rusty-red colour because of its high iron content, typically has a clay-like consistency and can hold water close to the surface almost indefinitely.  Frustratingly, Laterite is estimated to cover up to a third of the Earth’s surface, and is common in several countries, like Colombia, where landmines are an enormous problem.

Why are non-cooperative soils so important?

Finding new ways to detect landmines is only the starting point for most FABW funded research. The much bigger challenge for our researchers is making their ideas work outside the lab in real-world environments. The real world is full of non-cooperative soil types, so any new technology needs must address the issue early in the development process.

Critically, non-cooperative soils are not limited to particular countries or regions of the world. They can occur anywhere, often in small patches interspersed with less difficult soil types. To be effective, any new landmine detection technology must cope with non-cooperative soils effectively.

What Find A Better Way is doing to address the challenge of non-cooperative soils:

The challenge posed by non-cooperative soils is an issue nearly all Find A Better Way detection research projects face. Project PERUN, based at the University of Zagreb, is focused exclusively on the issue. By improving the design of commercially-available metal detectors, which have not changed significantly for several decades, and creating improved processing algorithms, Professor Vedran Bilas and his team hope to make all metal detection more adaptable to non-cooperative soil issues.

Project AQUAREOS at King’s College London fires radio waves at suspected landmines. Their device then listens for energy signatures which are produced when the radio waves are absorbed by explosive materials. Non-cooperative and wet soils play havoc with traditional so-called “resonant” radio antennas, disturbing the tuning and degrading the signal — just like what can happen with the antenna on your radio at home when it is disturbed. By using broad-spectrum ‘non-resonant’ antennae the team can be sure to catch the signal, but they will receive dozens of other unwanted signals in the process – everything from overhead power lines to local radio stations can show up in their results. “It’s like trying to overhear a whispered conversation across the room at a crowded cocktail party,” explains project researcher Dr Jamie Barras.  “That’s why perfecting ways to filter out this unwanted chatter is a big part of what we are doing for FABW.”

And these are just two of the ways FABW is dealing with non-cooperative soils.

Developing improved landmine detection technologies means addressing dozens of difficult issues, of which non-cooperative soils is just one. Find A Better Way is committed to overcoming all of these challenges. With your support we will be putting improved landmine detection technology in the hands of frontline deminers, making landmine detection easier, cheaper, and safer.