ViSAR: A 235 GHz radar for airborne applications

Integration and flight test results of a first of a kind airborne radar operating in the EHF (extremely high frequency) band is described. This radar, developed under the DARPA (Defense Advanced Research Projects Agency) ViSAR (Video Synthetic Aperture Radar) program operates at 235 GHz over multiple GHz of bandwidth and provides high resolution, video SAR imagery at a very low frame latency to support real time operations. The imagery is generated at a high refresh rate which provides the operator, whether on a manned platform or remotely piloted unmanned air vehicle (UAV) tactical situational awareness of moving targets or changes to stationary scene content. The system was flight tested onboard a DC-3 aircraft and flown in a variety of environmental conditions. The test results produced exceptional SAR imagery and ground moving target indicator (GMTI) detections to validate many model based assumptions about the operation and RF performance in this frequency band.