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Ground Penetrating Imaging Radar (GPIR)

DSED is using it's unique facilities, capabilities, and expertise in addressing problems of interest to the national infrastructure. One problem area that has been focused on is the quick and automated inspection of highway bridge decks.

The goal of the project is to acquire radar data of bridge decks at highway speeds for later reconstructive imaging and post processing.


The antenna array would be carried in a van at highway speeds and as the vehicle drives over the bridge structure, the radar would sweep out a synthetic aperture using the linear array of receivers. This data is then processed using the backward wave reconstruction techniques mentioned later.

These efforts are continuing. The following overview shows some of the results obtained from the experimental laboratory unit:

This photo shows the first experimental setup used in the project. Notice the x-y scanning system used to create a synthetic aperture.

This photo shows the inside of the test slab before the concrete was poured. Note the simulated defects, the rebars (in plastic tubes), the delamination simulation plates, and the spall simulators. This test slab was structurally designed to look like a bridge deck.

This view shows the upper portion of the reconstructed image generated by the backward wave imaging algorithms. The data was obtained from the radar data. Notice that the rebars, delaminations, and spalls are clearly visible in this upper view of the reconstruction.

(300K movie)
This animation sequence is a computational electromagnetic model of EM waves propagating through a simple soil model. The transmitter is located on the surface and launches a pulse into the soil. Notice the layer interface reflections, the target reflections, and the target mutual interaction. For clarity, the ground clutter has been removed from the model. Note that each frame has been autoscaled for visual wave tracking purposes (hence the color changes).

This project naturally breaks into three areas:

Hardware and Acquisition Systems
Computational Electromagnetic Modeling
Focused Reconstructive Imaging