Geophysical and Operational System Performance Tool for the detection of clandestine tunnels: Enhancement and case studies

Clandestine tunnels in the southwest border have posed a serious threat and are a growing concern for United States' national security. To address the challenges and the asymmetric threat they present, the Department of Homeland Security (DHS) Science and Technology Directorate (S&T) is presently leading the development of the Geophysical and Operational System Performance Tool (GOSPT) that can be used to assist technology acquisition, mission planning, and sensor performance assessment. The GOSPT combines subsurface geo-environmental data of the southwest border, geophysical models, and sensor physics to conduct tunnel detection system performance analysis. Its capabilities include physics based 1D, 2D and 3D high-fidelity numerical modeling and simulation of various sensor system/configurations in operational environments. False targets and clutter may also be added to the simulations to assess sensor performance under a variety of conditions. This paper describes several enhancements of the GOSPT, including using advanced spatial and temporal processing techniques, and geo-statistical modeling tools, to improve sensor detection performance characterization. In addition, a Java-based, fully integrated end-to-end sensor simulation environment was developed to allow interactive sensor performance prediction, providing an effective mechanism of exploring sensor system integration, hardware/software advancement and data fusion technology development. The tool enables system developers to quickly and precisely observe the effects on system performance to changes in sensor design and geological conditions. Case studies utilizing the GOSPT for assessing the performance of an existing ground penetrating radar system on a concrete-lined tunnel, and investigating potential improved detection capabilities using advanced sensor placement and coherent multiple element array technology will be discussed in the paper.