Detection of UXO-like Targets with Portable Transient Electromagnetic System

With the advantages of strong anti-interference ability and high spatial resolution, electromagnetic induction (EMI) has proven to be successful in unexploded ordnance (UXO detection. Portable transient electromagnetic system can work in a variety of complex conditions where the large and heavy vehicular systems cannot be readily used. The detection of UXO-like targets with portable transient electromagnetic (TEM) system is discussed detailed in this paper. Firstly, with description of the single dipole model for UXO response approximation, the location and characteristic response extraction for UXO-like targets is talked with the DE algorithm. Then, the improved sensor of the portable TEM system with a single-layered transmitting coil and five 3-component receiving coils is introduced. The transmitting coil is constructed with a diameter, number of turns, and transmitting current of 0.5 m, 30, and 5 A, respectively. The receiving coil is constructed with a length, number of turns, and resonant frequency of 6 cm, 600, and 180 kHz, respectively. Finally, 12 UXOs and 6 harmless targets buried in the area of 10 m × 6 m at different depths in different orientations have been detected with the improved portable TEM system. Target location and characteristic response have been estimated by DE algorithm with the measured response. The experimental results show that the high-quality data provided by the improved portable TEM system combined with the DE algorithm based on the dipole model can locate and characterize the separated targets accurately. Most of the position errors are within 10cm in x position and 5cm in depths for separated buried targets. For the multiple-targets buried together, the system can still locate and characterize the targets even if the response of two targets overlaps.