GPR Environmental-Based Landmine Automatic Detection

According to the United Nations, as of the year 2000 there were 70 million landmines planted in a third of the world’s nations affecting global causality rate of up to 20,000/year, (Anderson, 2002). That is why landmine detection has attracted much attention by many research teams around the world during the last two decades; among them is our research team in Nagoya University. Anti-personnel (AP) mine ranges from 5 to 15 cm in size; they can be metal, plastic, or wood. AP mines are normally buried at shallow depth; detonated by very low pressure, and designated to kill or maim people. PMN2, Type72 and PMN are examples, Fig. 1. In real world clearance activities, AP mine suspect areas are divided into 1 m grid squares, and each square meter is probed with a bayonet or plastic rod. Probing is done at an oblique angle to the ground so that the rod will encounter the side of a land mine and not trip the fuse. No need to say, this work is very dangerous and proceeds very slow, (Siegel, 2002). The need for a safer and more fast humanitarian demining action by replacing a manual sensing task by vehicle sensing task have motivated our research team to introduce a low-ground-pressure tires detection vehicle, (Hasegawa et al, 2004-A). The unmanned vehicle that can move in mine field without detonating a group of AP mines will be presented in this chapter. One of the big challenges in demining process is detection. If a mine is detected, deminers can explode, mark or move it to a pit for later detonation or defusing. Conventional mine detection, by a metal detector, is often difficult for two reasons. First, mines are increasingly being made of plastics, minimizing the more easily detectable metal components. Second, mined areas are often equipped with metal scraps creating a high false alarm rate. Because of the difficulty encountered in detecting the tiny amounts of metal in a plastic landmine with a metal detector, technology development has been extended to other sensors. Ground penetrating radar (GPR) used for about 70 years for a variety of geophysical subsurface imaging applications including utility mapping and hazardous waste container has been actively applied to the problem of land mine detection for nearly the last two decades of research. It provides sensing objects underground based on dielectric properties. It senses the reflected electromagnetic wave by a buried object. It is expected that GPR be a good alternative sensor and/or an important support sensor when fused with a metal detector for