DHS tries to find tunnels below the surface

摘要

The surface of the earth has been mapped and mastered, with lidar, photography, infrared and other now-familiar systems, on satellites, manned aircraft and drones. Thermal imagers can even penetrate thin layers of soil. But go just a bit deeper, and you reach one of the last frontiers of ISR. How do you see into solid ground, below the roads, the rocks and the desert sand? It's a hot topic in U.S. government research. Tunnels have bedeviled prisons, security forces and border agents for years. Last summer, authorities discovered a 240-yard drug tunnel, fitted with electricity and lights and and a ventilation system, under Arizona's border with Mexico. The year before, there was embarrassing news from Kandahar: Almost 500 prisoners, including Taliban fighters, escaped from an Afghan prison via a 1,000-foot tunnel.