Required Number of Degrees-of-Freedom for an Adaptive Optics System

Abstract

The ability of an adaptive optics system to compensate for turbulence induced random wavefront distortion is studied in terms of the ensemble-average, aperture-average squared residual wavefront error. It is shown that if the adaptive optics are controlled in terms of the appropriate set of Karhunen-Loeve functions, the minimum possible number of degrees of freedom will be required for a given performance. Results are presented for the required number of degrees of freedom for any level of performance if the adaptive optics control utilizes the Karhunen-Loeve functions, the Zernike function, a set of local piston/tilt-only functions, or a set of local piston-only functions. With the exception of the last of these, which requires almost seven times the optimum number of degrees of freedom, there is no more than a factor of two spread in required number of degrees of freedom amongst the other possibilities.

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Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1975
Accession Number
ADA339142

Entities

People

  • David L. Fred

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Adaptive Optics
  • Air Force
  • Angle Of Arrival
  • Atmospheric Motion
  • Ballistic Missiles
  • Coverings
  • Diameters
  • Distortion
  • Eigenvalues
  • Errors
  • Integral Equations
  • Optics
  • Polynomials
  • Residuals
  • Statistics
  • Turbulence
  • Wavefronts

Fields of Study

  • Physics

Readers

  • Approximation Theory.
  • Control Systems Engineering.
  • Optical Physics and Photonics.