Synthetic aperture radar- MiniSAR offers promise
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Weighing less than 30 pounds, Sandia National Laboratories' miniSAR (synthetic aperture radar) will be onefourth the weight and one-tenth the volume of conventional SARs that now fly on larger unmanned aerial vehicles (UAVs). It is the latest design produced by Sandia in a history that involves more than 20 years of related research and development.
Like the larger class of Sandia SARs, the new version will be able to take highresolution (four-inch) images through weather, at night and in dust storms. However, while the larger SAR, flown on platforms such as General Atomics' Predator, can produce an image from as far away as 35 kilometers with its larger antenna and higher transmitter power, the miniSAR is expected to operate at a range of about 15 kilometers -- more than adequate for most small UAV applications.
Future versions of the miniSAR are contemplated that will shrink the total weight to less than 10 pounds by leveraging both in-development and yetto- be developed Sandia microsystems technologies.
Current approach
George Sloan, Sandia's project lead for miniSAR development, created the current approach for miniaturized SARs with colleagues Dale Dubbert and Armin Doerry several years ago. The effort incorporated a number of key technologies, including mechanical design, digital miniaturization, radio frequency miniaturization and navigation expertise. Last November, after the Sandia teams got the miniSAR down to its diminutive 30 pounds, they introduced it at a UAV conference. Since then, more than 30 potential customers, including intelligence agencies, UAV manufacturers and major radar vendors, have visited Sandia to discuss possible licensing and use of the miniSAR.
"We look to make the miniSAR small, light, and affordable," Sloan says. The new design incorporates two major subsystems: The antenna gimbal assembly, a pointing system that consists of the antenna, gimbal and transmitter that sends the radio frequency signal and receives it back. The radar electronics assembly, combining signal generator, receiver and processors in an electronics package that generates radar signals, controls the system, processes the data and transforms it into an image.
Two applications
Sloan says the miniSAR will have two primary applications. First it will be used for reconnaissance on small UAVs that can carry a payload of 50 pounds, considerably less than existing radars. Second, it will then be adapted for use in precision-guided weapons. Current guidance systems for these weapons rely on target designation methods that are subject to jamming and have trouble operating in bad weather and dust storms. MiniSAR is resistant to these problems. Previous SAR versions were too big, too heavy and too expensive to use in precision-guidance applications.