Smart cars use radar for protection
As part of a National Highway Traffic Safety Administration program, the Environmental Research Institute of Michigan (ERIM; Ann Arbor, MI) has been studying the radar characteristics of roadway objects and cars. The radar data, says project engineer Paul Zoratti, is intended to aid developers, evaluators, and simulators of vehicle-based radar sensors. Zoratti expects such systems to be components of future collision-warning and adaptive cruise-control systems.
To produce vehicle profiles, Zoratti and his colleagues placed test vehicles onto a rotary platform. Then, using inverse-synthetic-aperture-radar techniques (ISAR), the vehicles` radar profiles were measured as the vehicles rotated 360.
"Because we used ISAR techniques," Zoratti says, "we were able to create two-dimensional radar movies of the automobiles tested." Such movies illustrate how the radar return levels vary as the vehicle is rotated and illustrate the effects of radar return levels with changing aspect angle. These movies were made with ERIM`s proprietary image-manipulation software and are only available to organizations performing research in this area.
To identify all the different scattering areas of an object, ERIM created an integrated radar image by integrating returns from multiple images. Such images appear as if you are viewing the vehicle from above with the object being illuminated from all angles simultaneously. "At present," says Zoratti, "this type of information can help to explain observations during static or roadway testing of vehicle-based radar sensors."