Electrical Conductivity Object Locator
Currently, millions of objects remain buried worldwide ranging from small-sized land mines to large-size waste disposal and storage drums. Many of these sites are current and former DoD installations, which are coming under remediation or reclamation. These sites contain everything from the motor pool, laundry, landfill, to an array of abandoned ordnance. In addition the techniques to locate, identify and characterize buried objects such as reinforcing bars, fibers and cracks in concrete structures, composite materials, and other metallic and non-metallic structures are in great demand. The most useful techniques are those that can locate, identify and characterize buried objects in real time.
The Johns Hopkins Applied Physics Laboratory has developed and patented apparatus and method for locating objects in a body through the mapping and imaging of the conductive profiles of such objects by applying a force to the object and/or body and measuring certain characteristics of the body response to the application of the force. The force applied to the object is in the form of an electrical voltage or current such that the electrical potential, currents and magnetic fields are generated throughout the subsurface site. The voltage, current or magnetic field is then measured at the surface, above the surface or at the boundary of the body. A global stochastic approximation technique is then used to estimate the subsurface conductivity and the location of the objects by minimizing a loss function. The loss function is formed from the total errors between the measured values from the sensors and the computed values from the conductivity profile and the locations of the objects by finite element method. The object locations and conductivities identify the object types and their material composition.
Dr. G. R. Jacobovitz
Phone: (443) 778-9899