GPR advances from Project DETERMINE at Cranfield University
Earlier this week representatives from Find A Better Way visited part of the advanced ground penetrating radar (GPR) project the charity is funding, known as Project DETERMINE. Spread across two institutions, Cranfield University and University College London, this visit was to the Cranfield campus at Shrivenham where project leader Dr. Ivor Morrow explained to us what he and PhD student Sebastian Wirth have been up to.
‘GPR has huge potential as a tool for the demining industry,’ Ivor explained, ‘but commercially available GPR cannot provide the detail or the precision necessary for detecting anti-personnel mines. It is perfectly adequate for finding a buried building wall if you are an archeologist, or approximating the depth of a building’s foundation or buried pipes if you are a structural engineer, but identifying something as small as a landmine (and being absolutely sure it is a landmine and not a rock or a buried coke can) is beyond current capabilities.’
The Project DETERMINE work at Cranfield is vastly improving GPR resolution by collecting several-times as much data as standard GPR through a process known as ‘full polarmetry.’ At the same time, the team are improving the software that helps filter out the surface and sub-surface clutter that accompanies radar signals and obscures the important information.
‘It’s not enough to simply make GPR more powerful,’ Ivor continued. ‘If you ramp up the power you get a lot more signal, but you also get a lot more unwanted noise along with it. By taking measurements from different angles and polarisations we are able to better filter out the unwanted clutter we get with any measurement, and clearly identify the real threats.’
In addition to improving GPR itself, Ivor and Sebastian are also testing the way different soil types, particularly types of non-cooperative soil, affect GPR signals. This is done by testing the way pulverized samples of different soil types behave in an electromagnetic field. A software algorithm ‘filter’ is then created which will help GPR processors compensate for the natural distortions that occur in real-life scenarios.
The Cranfield team are also developing a new type of GPR antenna they hope will be especially useful for demining in the field.
‘We can’t anticipate what sort of device our GPR will work best with, but we know the lighter and cheaper our equipment is the better. GPR antennas capable of the measurements we need are typically very heavy and can cost hundreds of pounds. We’ve started 3D printing plastic antennas and then electroplating them with copper where the metal parts would normally be. They are not only a fraction of the price, but can also be printed on-site and on-demand by deminers when and where they are needed.’
Project DETERMINE is currently mid-way through its current three-year funding agreement with Find A Better Way, and on course to deliver all of its objectives by the Autumn of 2018.