High frequency behavior of the tilt spectrum of atmospheric turbulence
Abstract
The necessity of using the exact form of the tilt power spectrum as defined by Hogge and Butts (1976, HB) to model high frequency tilt correction of atmospheric turbulence is demonstrated. It is shown that calculations performed with a restricted phase difference spectrum produce errors in the servo bandwidth requirements of a tracking system whose errors must be kept small. A random tilt causes a target to quiver in the focal plane of a tracking sensor, and yields an effective jitter. Turbulence tilt coefficients are defined by a least squares method or as coefficients of a Zernike expansion. Fourier transformations provide the tilt power spectra. Parallel approximation is compared for accuracy with exact calculations of a plane wave tilt spectra in the presence of a crosswind. An underestimation is produced by the parallel approximation, due to contributions of the nonphysical part of the tilt spectrum.
 Publication:

Applied Optics
 Pub Date:
 March 1983
 DOI:
 10.1364/AO.22.0645_1
 Bibcode:
 1983ApOpt..22..645F
 Keywords:

 Atmospheric Turbulence;
 Fourier Transformation;
 Frequency Response;
 Optical Tracking;
 Plane Waves;
 Power Spectra;
 Adaptive Optics;
 Approximation;
 Error Analysis;
 Focal Plane Devices;
 High Frequencies;
 Least Squares Method;
 Optical Correction Procedure;
 Phase Shift;
 Turbulence Effects;
 Communications and Radar;
 TURBULENCE;
 ATMOSPHERIC OPTICS