HR: 15:50h
AN: NS34A-02    [Abstracts]
TI: Integration of GPR and Laser Position Sensors for Real-Time 3D Data Fusion
AU: * Grasmueck, M
EM: mgrasmueck@rsmas.miami.edu
AF: University of Miami, RSMAS-MGG 4600 Rickenbacker Causeway, Miami, FL 33149 United States
AU: Viggiano, D
EM: dviggiano@rsmas.miami.edu
AF: University of Miami, RSMAS-MGG 4600 Rickenbacker Causeway, Miami, FL 33149 United States
AB: Non-invasive 3D imaging visualizes anatomy and contents inside objects. Such tools are a commodity for medical doctors diagnosing a patient's health without scalpel and airport security staff inspecting the contents of baggage without opening. For geologists, hydrologists, archeologists and engineers wanting to see inside the shallow subsurface, such 3D tools are still a rarity. Theory and practice show that full-resolution 3D Ground Penetrating Radar (GPR) imaging requires unaliased recording of dipping reflections and diffractions. For a heterogeneous subsurface, minimum grid spacing of GPR measurements should be at least quarter wavelength or less in all directions. Consequently, positioning precision needs to be better than eighth wavelength for correct grid point assignment. Until now 3D GPR imaging has not been practical: data acquisition and processing took weeks to months, data analysis required geophysical training with no versatile 3D systems commercially available. We have integrated novel rotary laser positioning technology with GPR into a highly efficient and simple to use 3D imaging system. The laser positioning enables acquisition of centimeter accurate x, y, and z coordinates from multiple small detectors attached to moving GPR antennae. Positions streaming with 20 updates/second from each detector are fused in real-time with the GPR data. We developed software for automated data acquisition and real-time 3D GPR data quality control on slices at selected depths. Standard formatted (SEGY) data cubes and animations are generated within an hour after the last trace has been acquired. Examples can be seen at www.3dgpr.info. Such instant 3D GPR can be used as an on-site imaging tool supporting field work, hypothesis testing, and optimal sample collection. Rotary laser positioning has the flexibility to be integrated with multiple moving GPR antennae and other geophysical sensors enabling simple and efficient high resolution 3D data acquisition at different GPR frequencies and polarizations. Existing GPR systems can be upgraded with a simple start-of-trace trigger modification and an investment similar to the cost of a standard GPR unit. This opens new opportunities for wider application of fully resolved 3D and 4D imaging in the near surface environment.
UR: http://www.3dgpr.info
DE: 0694 Instrumentation and techniques
DE: 0910 Data processing
DE: 0994 Instruments and techniques
DE: 1800 HYDROLOGY
DE: 9805 Instruments useful in three or more fields
SC: Near-Surface Geophysics [NS]
MN: 2005 Joint Assembly