An Innovative Algorithm for Ground Penetrating Radar (GPR ...
Graduate Category: Engineering and Technology Degree Level: Ph.D. Abstract ID# 540
An Innovative Algorithm for Ground Penetrating Radar (GPR) Detection of Concealed Subsurface Objects Mohammad M. Tajdini, Carey M. Rappaport, Borja Gonzalez-Valdes, and Jose A. Martinez-Lorenzo Electrical and Computer Engineering Department, Northeastern University, Boston, MA 02115 Abstract Ground penetrating radar (GPR) is an efficient tool for fast noninvasive sensing and localization of hidden subsurface objects. Air-coupled GPR can be vehicle mounted and driven at highway speeds. However, there are two important issues about GPR subsurface detection. The first problem is when the ground surface is rough, where the obscuring effect of the random rough soil clutter is a great obstacle in precise localization of buried objects. The second issue is when the ground surface material is not homogeneous, such as the GPR detection of deteriorated concrete bridge decks, when in addition to the fact that the bridge is made of different layers the strong scattering of reinforcing metal bars (rebars) changes the GPR response significantly. In this work, we propose an efficient method to simulate and remove the clutter noise in order to supplement the subsurface localization accuracy in both cases.
Ground Penetrating Radar (GPR) for Deteriorated Concrete Bridge Decks with a Grid of Rebars
A bridge deck with two layers of 3.8 cm asphalt at the top and 18.4 cm concrete below it reinforced by a grid of #4 rebars (d=15 cm) with a subsurface defect inside (D=7.5 cm). The GPR transmitter is a 2 GHz CW source 7.5 cm above the surface.
Synthetic Aperture Radar (SAR) Imaging of Realistic Rough Soil for Localization of Subsurface Threats Antenna Array
Rough Soil
Actual surface (left) and reconstructed surface (right), using SAR imaging method in the frequency band-width of 8-12 GHz via a 2D array of monostatic antennas with 60° incident angle 2 m above the surface. Scattered electric field by a) analytic method and b) FDFD method.
Received electric field from a y-directed electric dipole 5 cm above the rough surface at z= 4 cm by direct FDFD method (left) and analytic/FDFD method (right) which is a much faster method.
Conclusions a) The scattering effect of rebar and b) the wave propagation of GPR through the bridge itself. The surface of the bridge deck is at z=0 cm. Analytically simulated electric field on the surface of the concrete bridge deck; a) reinforced bridge deck with embedded sphere, b) reinforced bridge deck alone c) difference due to the hidden defect.
A numerical investigation for GPR detection of subsurface objects is presented here. The GPR sensing for concrete bridge decks with a grid of rebars and some hidden subsurface defects is based on the Green’s function analysis of the structure in combination with method of moments (MoM). The reconstruction of the soil surface exploits the SAR imaging via the calculation of reflection from the soil. The rough surface is simulated and its additive clutter is subtracted in another frequency from the measured data.
References [1] W. C. Chew, Waves and Fields in Inhomogeneous Media, IEEE Press, 1995. [2] M. M. Tajdini and C. M. Rappaport, “An efficient forward model of ground penetrating radar for sensing deteriorated bridge decks,” presented in 2013 IEEE AP-S/USNC-URSI Symp., Orlando, FL, 2013.
An Innovative Algorithm for Ground Penetrating Radar (GPR) Detection of Concealed Subsurface Objects Mohammad M. Tajdini, Carey M. Rappaport, Borja Gonzalez-Valdes, and Jose A. Martinez-Lorenzo Electrical and Computer Engineering Department, Northeastern University, Boston, MA 02115 Abstract Ground penetrating radar (GPR) is an efficient tool for fast noninvasive sensing and localization of hidden subsurface objects. Air-coupled GPR can be vehicle mounted and driven at highway speeds. However, there are two important issues about GPR subsurface detection. The first problem is when the ground surface is rough, where the obscuring effect of the random rough soil clutter is a great obstacle in precise localization of buried objects. The second issue is when the ground surface material is not homogeneous, such as the GPR detection of deteriorated concrete bridge decks, when in addition to the fact that the bridge is made of different layers the strong scattering of reinforcing metal bars (rebars) changes the GPR response significantly. In this work, we propose an efficient method to simulate and remove the clutter noise in order to supplement the subsurface localization accuracy in both cases.
Ground Penetrating Radar (GPR) for Deteriorated Concrete Bridge Decks with a Grid of Rebars
A bridge deck with two layers of 3.8 cm asphalt at the top and 18.4 cm concrete below it reinforced by a grid of #4 rebars (d=15 cm) with a subsurface defect inside (D=7.5 cm). The GPR transmitter is a 2 GHz CW source 7.5 cm above the surface.
Synthetic Aperture Radar (SAR) Imaging of Realistic Rough Soil for Localization of Subsurface Threats Antenna Array
Rough Soil
Actual surface (left) and reconstructed surface (right), using SAR imaging method in the frequency band-width of 8-12 GHz via a 2D array of monostatic antennas with 60° incident angle 2 m above the surface. Scattered electric field by a) analytic method and b) FDFD method.
Received electric field from a y-directed electric dipole 5 cm above the rough surface at z= 4 cm by direct FDFD method (left) and analytic/FDFD method (right) which is a much faster method.
Conclusions a) The scattering effect of rebar and b) the wave propagation of GPR through the bridge itself. The surface of the bridge deck is at z=0 cm. Analytically simulated electric field on the surface of the concrete bridge deck; a) reinforced bridge deck with embedded sphere, b) reinforced bridge deck alone c) difference due to the hidden defect.
A numerical investigation for GPR detection of subsurface objects is presented here. The GPR sensing for concrete bridge decks with a grid of rebars and some hidden subsurface defects is based on the Green’s function analysis of the structure in combination with method of moments (MoM). The reconstruction of the soil surface exploits the SAR imaging via the calculation of reflection from the soil. The rough surface is simulated and its additive clutter is subtracted in another frequency from the measured data.
References [1] W. C. Chew, Waves and Fields in Inhomogeneous Media, IEEE Press, 1995. [2] M. M. Tajdini and C. M. Rappaport, “An efficient forward model of ground penetrating radar for sensing deteriorated bridge decks,” presented in 2013 IEEE AP-S/USNC-URSI Symp., Orlando, FL, 2013.
