Underground Tunnel Detection Across Border Areas

Tunnels are considered as the oldest method of passageway. Underground tunnels are popular from olden eras for connecting places, travelling, and aid for various surface threats. They are also used for illegal activities like smuggling of unlicensed drugs, weapons, currency, gold, explosives, and even human trafficking is being done through these tunnels. These immoral activities are concentrated in national border areas in order to escape from the border security measures. Hence the detection processes of such tunnels in the national security border areas are necessary in order to protect our homeland security systems. The geology plays an important role in the detection of the underground tunnel system procedures. There is no perfect system for the tunnel detection and localization and even today the tunnels revealed in coincidence. The basic principle to find the hollow space (tunnel) is, by sending an ultrasonic frequency signal into the ground, and study the reflected beam from the tunnel or the hollow space. By analyzing the reflected signal characteristics, preliminary detection of a tunnel/void is possible. Basic idea of the detection is to perform the range estimation algorithm (REA) by pulse echo method. From these, we can estimate the depth of the tunnel. The characteristics of the signal at the soil-tunnel (air) reflection interface are to be investigated.