Test and evaluation of Japanese GPR-EMI dual-sensor systems at Benkovac Test Site in Croatia

This chapter presents an experimental design and the evaluation results of trials that were carried out from 1 February to 9 March 2006 using real PMA-1A and PMA-2 landmines at the Benkovac test site in Croatia. The objective of the Croatia-Japan joint trial is to evaluate dual sensor systems, which use both ground-penetrating radar (GPR) and electromagnetic inductive (EMI) sensors. A comparative trial was also carried out by Croatian deminers using an existing EMI sensor, i.e., a metal detector. The trial aimed to evaluate differences in performance between dual sensors and metal detectors, especially in terms of discrimination of landmines from metal fragments and extension of the detectable range in the depth direction. The devices evaluated here are four prototypes of antipersonnel landmine detection systems developed under a project of Japan Science and Technology Agency (JST), the supervising authority of which is the Ministry of Education, Culture, Sports, Science and Technology (MEXT). The prototypes provide operators with subsurface images, and the final decision as to whether a shadow in the image is a real landmine or not is left to the operator. This is similar to the way that medical doctors find cancer by reading CT images. Since operators' pre-knowledge of the locations of buried targets significantly influences the test result, three test lanes, which have three different kinds of soils, were designed to be suitable for blind tests. The results showed that the dual sensor systems have a potential to discriminate landmines from metal fragments and that the probability of detection for small targets in mineralized soils can be improved by using GPR.