Improved passive millimeter-wave imaging from a helicopter platform

A second-generation passive millimeter-wave imaging system is being prepared for flight testing on a UH-1H "Huey" helicopter platform. Passive millimeter-wave sensors form images through collection of blackbody emissions in the millimeter-wave portion of the electromagnetic spectrum. Radiation at this wavelength is not significantly scattered or absorbed by fog, clouds, smoke, or fine dust, which may blind other electro-optic sensors. Additionally, millimeter-wave imagery depends on a phenomenology based on reflection rather than emission, which produces a high level of contrast for metal targets. The system to be flight tested operates in the W-band region of the spectrum at a 30 Hz frame rate. The field-of-view of the system is 20 x 30 degrees and the system temperature resolution is less than 3 degrees. The system uses a pupil-plane phased-array architecture that allows the large aperture system to retain a compact form factor appropriate for airborne applications. The flight test is to include demonstrations of navigation with the system in a look-forward mode, targeting and reconnaissance with the system in a look down mode at 45 degrees, and landing aid with the system looking straight down. Potential targets include military and non-military vehicles, roads, rivers, and other landmarks, and terrain features. The flight test is scheduled to be completed in April 2004 with images available soon thereafter.