Infrared Sky and Terrain Radiances in a Coastal Region
Abstract
Models of atmospheric and terrain infrared backgrounds in coastal regions are of special importance to designers of electro-optical systems to aid in sensor specification, and to ship commanders in optimizing the use of smart weapons against an adversary in different locales. Fleet units operating in coastal regions in support of amphibious operations must be able to determine the standoff ranges at which they can detect and track incoming aircraft or guided weaponry using passive infrared sensors (low-light level TV, FLIR, or IRST). Determinations of these standoff ranges is important in order to estimate the times allowable for evasive action and the deployment of countermeasures. In most situations, threat vehicles approaching from the land will have a smaller radiance contrast with their background than those approaching from the colder regions of the sky, thus allowing less time for target acquisition or evasive actions. Models of expected sky/terrain backgrounds and meteorological conditions in different locales need to be developed for use in real-time system performance prediction codes and for use in system design. This report, presents atmospheric and terrestrial infrared (8 to 12 microns) radiances measured in the San Diego, California coastal region using an AGA Model 780 THERMOVISION infrared imaging system. Examples of daytime background radiances are analyzed to compare the mean equivalent blackbody temperatures of the terrain and the overlying sky during different solar heating conditions. Recommendations for further measurements and improvements to the present data acquisition system are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1989
- Accession Number
- ADA210120
Entities
People
- H. G. Hughes
Organizations
- Cold Regions Research and Engineering Laboratory