Emmett Perl
University:
Gradation Date: Spring 2011
Hometown:
My Project: Through-Barrier Radar Detection and Imaging
The ability to detect and image objects through various materials has many applications to law enforcement, emergency response, and the military. With recent advances in radar technology, through-barrier radar systems are beginning to emerge in the real world to detect objects or people hidden behind visual obstructions. However, there are many challenges that must be overcome before through-barrier radar can reach its true potential. No standard has been developed to evaluate these systems and universal metrics are required. For this reason, we are developing a standard test method to characterize these systems. We acquired a Constant Look Radar System, centered around 3.6 GHz (λ≈83mm), with through-barrier capabilities to carry out our tests. We also designed and built a test apparatus to simulate a moving target, which allows us to control the vibration (frequency and displacement) of a 20 cm × 20 cm square aluminum plate. By aiming our radar system toward the aluminum plate, we are able to distinctly see its Doppler signature.
Our radar system collecting data on a vibrating aluminum plate
To find the minimum signal that the radar could detect, we varied the displacement of the plate. We found that the radar could pick up a vibration as small as 20 micrometers across a distance of 4 meters (~13 feet). Then, by varying the frequency of vibration, we were able to determine the frequency response of our radar system. We found that the sensitivity of our system varies in a predictable manner across its range of Doppler frequencies. We have recently started testing the ability of our system to detect these displacements through walls by measuring the signal attenuation caused by various construction materials. So far, we have found that the loss in signal through masonry block is around 15 dB, and the loss through concrete is around 28 dB, which is consistent with previous NIST studies on the propagation properties of these materials. We are currently testing our system with other building materials to characterize its ability to penetrate a variety of walls. As the project continues, we will begin to add variables, such as changing the angle of incidence or combining different walls, in order to simulate a real world situation.
Aluminum plate attached to a shaker that controls the frequency and displacement of the plate
