Use of Ground Penetrating Radar for Locating Contraband Aboard Ocean Going Vessels: Feasibility Study

摘要

Ground Penetrating Radar (GPR) surveys were conducted over various stockpiled materials at the Alabama state Docks located in Mobile, AL, to determine whether GPR is a viable method for rapidly detecting contraband materials buried in the cargo holds of ocean going vessels. The surveys were conducted by burying various objects including a contraband simulant (a bundle of four 10-lb bags of sugar duct-taped together) in stockpiled materials available at the site. The stockpiled materials tested were crystal gypsum, powdered gypsum, crushed pumice, coarse coal, fine coal, and bauxite. Two GPR systems, the pulseEKKO 1000 and the Noggin Plus systems, manufactured by Sensors & Software, Inc., were used to conduct the surveys. GPR surveys were run over the stockpiled materials using a suite of antenna frequencies ranging between 225 and 900 MHz to determine the effects of material type on depth of penetration and target resolution. All of the antennas tested were successful in detecting the location of the contraband simulant in at least one of the stockpiled materials. The 225 and 250 MHz antennas had the highest percentage of detecting the simulant in the stockpiled materials (60 and 90 percent, respectively) whereas the 900 MHz antenna had the lowest (30 percent). All antennas tested have penetration depths of greater than 1.5 in. The GPR surveys run on the different stockpiled materials at the Alabama State Docks demonstrate that GPR is a feasible means of locating contraband buried to depths of at least 1 to 2 in (limit of testing). However, the probability of success of locating contraband with GPR on board ships depends on the size and depth of the target as well as the magnetic and electrical properties of the target and the material in which it is hidden.