Maj J. Chris Zingarelli (USAF AFIT/ENG), Lt Col Travis Blake (DARPA/TTO – Space Systems), Stephen Cain (USAF AFIT/ENG)
Keywords: SSA
Abstract:
The state of the art Space Surveillance Telescope (SST) operates with a mechanical shutter thats speed restricts the telescope to long exposure imagery. Long exposure imagery consequently averages the atmosphere, which creates a point spread function (PSF) which can mimic one that contains fixed aberrations such as focus and spherical error. Focusing of the telescope is conducted by retrieving phase information in the image to determine the amount of defocus and then moving the mirrors axial to shift the focal point. The average atmosphere masks the static aberrations of the telescope in the image affecting the ability to achieve an optimal focus. This paper will explore the joint estimation of the focus and the atmospheric seeing parameter. The Cramer-Rao lower bounds for variance are computed to facilitate an understanding of the joint estimation problem. These bounds will serve to demonstrate how the average atmospheric transfer function makes sensing a focus error more difficult in the presence of noise.
Date of Conference: September 11-14, 2012
Track: Poster