21 August 2009 Evaluation of a cone tracking algorithm for free-space optical communication in direct mode
Author Affiliations +
Proceedings Volume 7464, Free-Space Laser Communications IX; 74640Y (2009); doi: 10.1117/12.826602
Event: SPIE Optical Engineering + Applications, 2009, San Diego, California, United States
The implementation of cone tracking to optimize the beam pointing in a retro-reflective link was reported in prior work [1]. One parameter required to close the loop is the phase difference between the scanning signal and the reflected modulated power, which gives the direction of the error. The phase difference is easy to measure in a retro-reflective link because the beam is reflected back to the transmitter making the feedback signal locally available. In a direct mode configuration, this phase difference is unknown. The problem was avoided in prior work [2] by using two detectors a few inches apart. This paper presents the results of the evaluation, using simulation, of an algorithm that estimates and tracks the phase difference between the two ends of the link making it possible to close the loop and insure convergence. It also shows how to implement the feedback path without using an additional beam as opposed to using an additional high-power wide-divergence beam.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Eric Saint Georges, "Evaluation of a cone tracking algorithm for free-space optical communication in direct mode", Proc. SPIE 7464, Free-Space Laser Communications IX, 74640Y (21 August 2009); doi: 10.1117/12.826602; https://doi.org/10.1117/12.826602


Unified MMSE estimation for GMSK signals with turbo codes
Proceedings of SPIE (August 10 2004)
Data screening for kinematic orbit determination of LEOs
Proceedings of SPIE (January 04 2006)
An all-digital demodulation scheme for DVB-S2
Proceedings of SPIE (January 04 2006)
BER estimation for multilevel modulation formats
Proceedings of SPIE (December 01 2009)

Back to Top