A radar system from Ohio State University engineers uses signals resembling random noise, creating a signal that is virtually undetectable.
Explains Eric K. Walton, senior research scientist at OSU's ElectroScience Laboratory. "Radio receivers could search for this (stealth) radar signal and not find it. The radar scatters a low-intensity signal across a wide range of frequencies. A TV or radio tuned to any single frequency would interpret the radar signal as weak static."
The radar can be tuned to penetrate solid walls. This would let military personnel spot enemy soldiers inside a building. Traffic police could measure vehicle speed without setting off drivers' radar detectors. And autonomous vehicles could tell whether a bush conceals a more dangerous obstacle, such as a tree stump or gully.
Search-and-rescue is another potential application. Conventional radar systems are too far-sighted to locate survivors buried in rubble nearby. The noise radar, in contrast, "can see objects just a couple of inches away with as much clarity as those on the Martian surface," says Walton. With further development, the radar might image tumors, blood clots, and foreign objects in the body. OSU is expected to license the patented radar system.