Accession Number : AD0763893

Title :   An Analysis of Solar Illuminated Terrain as a Source of Irradiation in Ground Target Signature Modeling.

Descriptive Note : Memorandum rept.,

Corporate Author : BALLISTIC RESEARCH LABS ABERDEEN PROVING GROUND MD

Personal Author(s) : Downs,Alan R.

Report Date : JUN 1973

Pagination or Media Count : 93

Abstract : The sun (moon), sky, and ground can all serve as irradiation sources contributing to a reflective target signature. The absolute and relative magnitudes of the effects of these sources vary widely with the geometric and environmental conditions. The report addresses the manner in which the relative magnitudes of the three effects vary with the parameters of interest for a cloudless daytime sky. To do this, empirical expressions for sky and ground brightness were integrated over the hemisphere contributing to the irradiance incident on a one square cm target and compared to the solar contributions. This comparison was made for a number of geometric configurations, for visibilities between 5 and 50 kilometers, for wavelengths between 0.425 and 1.625 micrometers, and for grassy and sandy terrains. The results are presented in tabular form. A discussion of error sources is also included. (Author)

Descriptors :   (*SOLAR RADIATION, ILLUMINATION), (*SURFACE TARGETS, *SPECTRUM SIGNATURES), SKY BRIGHTNESS, TERRAIN, REFLECTION, SCATTERING, TARGET DISCRIMINATION

Subject Categories : Infrared Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE