For decades, hostile combatants have used networks of underground tunnels and passageways to fight US troops. Instances of “tunnel warfare” can be seen in both world wars, Vietnam, and even nowadays in Iraq and Afghanistan. US forces have struggled to locate these underground passageways for a long time, to the point where it’s hindered their progress on past battlefronts.
That has since changed as the battlefield has modernized. The US Army Engineer Research and Development Center (ERDC) at the Geotechnical and Structural Laboratory in Vicksburg, Mississippi, developed a device known as the Rapid Reaction Tunnel Detection (R2TD) System. The device detects the underground voids formed by tunnels, along with sounds made by people or objects, using ground penetrating radar with an electromagnetic induction system.
The R2TD uses multiple sensors to pick up acoustic and seismic energy, and can use its detection equipment to remotely transmit its findings to analysts who view the data in graphical form. The device can be carried by a soldier or used inside a vehicle to scan potential tunnel areas, and takes just one day to train an operator. Combat engineers that used the system have given positive feedback, and indicated they like the ease of use and data displays. The R2TD has also been used by the Department of Homeland Security, along with other military services and allies.
While technology capable of detecting tunnels has been around for the past few decades, these systems have reached the current levels of accuracy and sophistication in recent years. R2TD has been used on the battlefront since 2014, however, the enemies who use these tunnels that this device seeks out have managed to continually adapt by building tunnels deeper underground in a more discrete manner. In addition to its sophisticated tunnel detection system, a passive sensing system uses a linear array of sensors just below the surface of the ground to monitor and process acoustic and seismic energy, which also can be monitored remotely.
The ERDC responded to this by trying to stay at least one step ahead and continually refining the software algorithms used to reject false positives and negatives. The system upgraded to a higher power cable-loop transmitter that sends signals deeper underground. The system’s ability to detect tunnels deeper underground improved as a result, along with the technology’s ability to sense underground head and infrastructure signals, which can differentiate between normal and underground movement.
Filed Under: M2M (machine to machine)