Preliminary investigation of the reststrahlen phenomenology at low-grazing angles

Detection of buried and flush buried landmines has been dangerous and time consuming for both military and humanitarian de-mining personnel throughout the world. In an effort to make the process safer, faster, and more reliable, scientists have successfully employed Ground Penetrating Radar (GPR) systems in nadir and near nadir viewing angles. Leveraging this successful technology, Forward-Looking Ground Penetrating Radar (FLGPR) technology, using low grazing angles, is being developed which promises to provide an increase in detection stand-off distance thereby increasing safety of personnel during land-based mine detection efforts. However, the application of GPR for the detection of buried plastic mines has been problematic, research has begun to exploit the comination of broadband and hyper-spectral passive electro-optical technologies with GPR technologies. One such embodiment is to use Forward Looking InfraRed (FLIR) technology with the intention to augment the capability of, and overcome limitations inherent to, current FLGPR technology. The emphasis in using FLIR is to understand and exploit specific spectral features which are complementary fo FLGPR and exhibited by buried metal and plastic mine targets. One spectral feature being investigated is the resstrahlen emission which results when soil is excavated or disturbed. This paper is a preliminary investigation of the performance of a vehicle based FLIR camera system for detecting resstrahlen emissions from disturbed soils. Specifically, this paper will examine the robustness of the resstrahlen feature in a forward-looking low grazing angle application. The data presented in this paper was collected at an eastern US Army testing site over targets deployed in soils which had been disturbed from one day before the start of the collection.