Accession Number : ADA309638

Title :   Infrared System Performance. Atmospheric Transmission, and Modeling Errors.

Descriptive Note : Final rept. Jan-Dec 95,

Corporate Author : INSTITUTE FOR DEFENSE ANALYSES ALEXANDRIA VA

Personal Author(s) : Biberman, Lucien M.

PDF Url : ADA309638

Report Date : MAR 1996

Pagination or Media Count : 65

Abstract : This paper focuses on atmospheric transmission and its effect on the performance of an infrared sensor at a given location, season, and time of day. Atmospheric transmission is often simply taken to be the value defined by a season, a geographic location, and an altitude. In fact, the character of the atmosphere changes, often rapidly, affecting transmission. The characteristics of airborne targets are so different from those of shipping or most terrain based targets that the target often, if not always, dominates the choice of the spectral band to be used. The large variability in weather, and thus atmospheric properties, combined with the large range in target characteristics, combine to produce a very complex and not readily understood situation. For a tolerable range of extinctions, the choice of a band between 3 and 5 micrometers for airborne targets with prominent plumes appears more useful more of the time than the band between 8 and 10 micrometers. For the longer wavelengths, the absolute humidity is the serious factor, while for the shorter wavelength the relative humidity is the critical factor. These factors indicate the potential desirability of dual band systems.

Descriptors :   *PERFORMANCE(ENGINEERING), *INFRARED EQUIPMENT, WEATHER, TERRAIN, FREQUENCY BANDS, SEASONAL VARIATIONS, INFRARED DETECTORS, AERIAL TARGETS, DUAL MODE, BAND SPECTRA, HUMIDITY, ATMOSPHERIC PHYSICS, TRANSMISSIVITY.

Subject Categories : Infrared Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE