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Proceedings Paper

Maximum-likelihood-based extended-source spatial acquisition and tracking for planetary optical communications
Author(s): Haiping Tsou; Tsun-Yee Yan
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Paper Abstract

This paper describes an extended-source spatial acquisition and tracking scheme for planetary optical communications. This scheme uses the Sun-lit Earth image as the beacon signal, which can be computed according to the current Sun-Earth-Probe angle from a pre-stored Earth image or a received snapshot taken by other Earth-orbiting satellite. Onboard the spacecraft, the reference image is correlated in the transform domain with the received image obtained from a detector array, which is assumed to have each of its pixels corrupted by an independent additive white Gaussian noise. The coordinate of the ground station is acquired and tracked, respectively, by an open-loop acquisition algorithm and a closed-loop tracking algorithm derived from the maximum likelihood criterion. As shown in the paper, the optimal spatial acquisition requires solving two nonlinear equations, or iteratively solving their linearized variants, to estimate the coordinate when translation in the relative positions of onboard and ground transceivers is considered. Similar assumption of linearization leads to the closed-loop spatial tracking algorithm in which the loop feedback signals can be derived from the weighted transform-domain correlation. Numerical results using a sample Sun-lit Earth image demonstrate that sub-pixel resolutions can be achieved by this scheme in a high disturbance environment.

Paper Details

Date Published: 26 April 1999
PDF: 8 pages
Proc. SPIE 3615, Free-Space Laser Communication Technologies XI, (26 April 1999); doi: 10.1117/12.346183
Show Author Affiliations
Haiping Tsou, Jet Propulsion Lab. (United States)
Tsun-Yee Yan, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 3615:
Free-Space Laser Communication Technologies XI
G. Stephen Mecherle, Editor(s)

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