Last year, I wrote about the early days of mine detecting vehicles in Rhodesia and South Africa, of which I had a certain amount of personal experience. They progressed from looking for metallic land mines, to using ground-penetrating radar to look for the holes dug to take them (which allowed them to look for plastic or wood mines as well).
Now the same approach appears to offer promise when adapted to small, low-cost drone aircraft.
Most civilized nations ban the use of landmines because they kill indiscriminately, and for years after they are planted. However, they are still used in many places around the world, and people are still left trying to find better ways to find and remove them. This group is looking at an interesting new approach: using ground-penetrating radar from a drone [PDF link].
The idea is that you send out a radio signal, which penetrates into the ground and bounces off any objects in there. By analyzing the reflected signal, so the theory goes, you can see objects underground. Of course, it gets a bit more complicated than that (especially when signals get reflected by the surface and other objects), but it’s a well-established technique even though this is the first time we’ve seen it mounted on a drone. It’s a great idea: the drone allows you to have the transmitting and receiving antennas separated with both mounted on pole extensions, meaning that the radio platform can move. Combined with a pre-planned flight, and we’re looking at a system that can fly over an area, scan what is under the ground, and store the data for analysis.
. . .
The trials on the device look promising: the team was able to detect several metal objects in a number of different soil types.
There's more at the link, and at the linked report (although that's much more technical). Very interesting reading.
This is potentially very useful indeed. Such drones can be carried by almost every vehicle in a convoy, if necessary, as their low cost will make them essentially a convenient spare part. They can inspect, not just the road surface, but the shoulders of the road, pull-off points, parking and rest areas, and so on. They can be far more effective than a surface-vehicle-mounted detection system, which can only detect objects over or near which it drives (to possibly detrimental effect if it sets them off). Being airborne, they are much less subject to the risk of explosion - although an inevitable countermeasure is likely to involve setting up extended tilt fuses using the thinnest, lightest materials possible, in an effort to blow up a drone as it passes over a mine. I've already seen some that used a transparent drinking straw filled with typical local surface dirt, which was very difficult to see in time to avoid it while driving at speed over an unpaved road. I daresay a higher-tech solution will be along shortly.
In my days in uniform, we'd probably have done just about anything, up to and including assault and maiming, to get our hands on something like this. I'm sure US forces in Afghanistan and other operational areas will do the same today. Kudos to the experimenters. Now, how soon can this be perfected and put into operation?