Real time passive millimeter-wave imaging from a helicopter platform

Real time passive millimeter-wave imaging systems have a wide variety of uses from aircraft navigation and landing in fog to detection of concealed weapons. A useful imaging system for flight platforms requires a large number of pixels and a high frame rate combined with a small antenna volume and a low cost. We present a millimeter-wave imaging system which uses 32 MMIC low noise amplifiers to display a 60×75 pixel image at a 30 Hz frame rate. The system´s pupil-plane phased array architecture allows for a relatively thin large aperture antenna. A remotely located processor utilizes microwave guiding circuit boards to perform phase and frequency discrimination on the radiation received by the antenna array. The imaging system was mounted on a helicopter platform and used to gather real-time imagery of a variety of targets. Targets include improved and unimproved runways, roadways, vehicles on roadways, and power lines. We present video-rate millimeter-wave imagery of ground features which are obscured from visible and infrared sensors by fog. The helicopter is shown to be able to follow and navigate ground features while travelling above a layer of fog using only the millimeter-wave imagery