Outer Scale and Diffraction Influences on Observed Angle-of-Arrival Variance

Abstract : Analysis of turbulence distorted imagery may allow turbulence strength (C2 n) to be estimated based on observed object motions (angle-of-arrival variations) in multi-frame image sequences. Such estimation methods would be useful when measured scintillometer data is unavailable, but should account for outer scale and diffraction effects, as these may influence the C2n turbulence strength prediction. The present paper analyzes these effects on single-axis angle-of-arrival variance for the case of spherical wave propagation and homogeneous turbulence properties. The analysis indicates outer scale influences may be significant, depending on the height of the line of sight and the system aperture size.