Backscatter Limitations in Active Night-Vision Systems

This study explores atmospheric backscatter as a fundamental limitation in using an artificial light source for night viewing. A mathematical model of an active night-vision system is constructed, and formulas are derived for the signal received from a target and the backscatter caused by the intervening atmosphere. Signal-to-noise ratio is defined, and its use as a measure of system performance is discussed. Several hypothetical systems are evaluated, and graphs of the signal-to-noise ratio as a function of range are presented. Additional graphs show the power that would be required by the systems to achieve a given signal-to-noise ratio as a function of range.