128 x 128 Pixel long wavelength infrared acquisition camera

Conference · Sat Dec 31 00:00:00 EST 1994

OSTI ID:207947

LeVan, P D; Colucci, D; Cowan, W D; Figie, B D; Stewart, E J ^[1]

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1. Phillips Lab., Kirtland AFB, NM (United States)

This paper describes a Phillips Laboratory internal design for a high sensitivity, large field of view infrared acquisition camera. Currently, the acquisition of a satellite with the 1.5 meter telescope of the Starfire Optical Range typically requires a sunlit target and dark sky. However, the level of thermal radiation from such a satellite is often sufficiently high in the Long Wavelength Infrared (LWIR) to permit detection with ground based telescopes irrespective of target illumination. The drawbacks of LWIR acquisition include the high levels of thermal radiation from both the telescope and the atmosphere which pose two constraints: (1), the ``background signal`` usually exceeds the target signal and must be removed on time scales over which it is relatively constant, and (2), associated with the background signal is a noise level that dominates all system noise sources. The background signal level at the detector array for the application varies between 10{sup 15} to 10{sup 16} photons sec{sup {minus}1} cm{sup {minus}2}, depending on the infrared bandpass used. The optical design for the LWIR acquisition camera maps a 128 x 128 pixel detector array onto a two milliradian (mrad) scene. The optical design uses two aspheric lenses, one to re-image the field onto a cold field stop, and the telescope pupil onto a cryogenic chopping mirror and collocated radiation stop. The second lens re-images the field stop onto the detector array. Aberrations are designed to be better than diffraction limited over the entire two mrad field of view. The end product of the acquisition system is a video display of the infrared scene, with the background signal removed. A user then positions mouse-driven cross hairs over a target in the scene. The resulting position and time update is used to revise the target ephemeris, and to provide pointing information for target acquisition by other SOR tracking platforms.

• OSTI ID: 207947
• Report Number(s): CONF-940449-; ISBN 0-8194-1521-9; TRN: IM9616%%275
• Resource Relation: Conference: Society of Photo-Optical Instrumentation Engineers conference on intelligent information systems, Orlando, FL (United States), 4-8 Apr 1994; Other Information: PBD: 1994; Related Information: Is Part Of Aerial surveillance sensing including obscured and underground object detection; Cindrich, E.; Del Grande, N.K.; Gowrinathan, S.; Johnson, P.B.; Shanley, J.F. [eds.]; PB: 443 p.; Proceedings/SPIE, Volume 2217
• Country of Publication: United States
• Language: English

Related Subjects

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
INFRARED RADIATION
RADIATION DETECTION
CAMERAS
DESIGN
SATELLITES
SIGNAL-TO-NOISE RATIO
OPTICAL SYSTEMS
DATA ACQUISITION SYSTEMS
DIGITAL SYSTEMS
ANALOG SYSTEMS
CRYOGENICS
MILITARY EQUIPMENT