Closed-Cycle Refrigeration for an Airborne Illuminator

Abstract

The U.S. Army’s NVASS Night Vision System is a helicopter-mounted, direct-view, night-vision reconnaissance system. An infrared illuminator consisting of a closed-cycle cooler, diode array, vacuum chamber, vac-ion pump, and pulsing electronics is mounted on the nose of a helicopter to provide covert illumination on the target scene. Reflected energy is sensed by a range-gated image-intensifier tube through a viewer assembly which extends from the crew compartment below the helicopter. Also extending below the helicopter is a ruby laser which performs ranging and target-designation functions. A digital computer displays target coordinates in UTM format. The operator views a fixed field-of-view scene presented by the image-intensifier tube through a binocular eyepiece. He can control the system, including illuminator, viewer, and laser, to scan a full 360° in azimuth and 0 to 70° in elevation.