An Experimental Spatial Acquisition and Tracking System for Optical Intersatellite Crosslinks
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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Optical intersatellite communications crosslinks will operate with much higher antenna gains and hence more stringent pointing and tracking requirements than do present RF and microwave-based systems. The design and experimental demonstration of an optical heterodyne communications receiver that includes an integrated 2-axis spatial acquisition subsystem and heterodyne tracker are presented. Requirements for the acquisition and tracking system are derived from the Laser Intersatellite Transmission Experiment LITE. The acquisition subsystem employs a parallel search algorithm using a direct detection, charge-coupled device CCD array. The heterodyne spatial tracker is based upon angle detection in the pupil plane. It uses a commutating, correlation demodulation scheme to reduce front-end-noise-induced biases relative to those from square law detection in the track channel alone. A robust handoff algorithm is presented for the transition between CCD-based acquisition and heterodyne spatial tracking. Results from a laboratory demonstration system are presented.
- Unmanned Spacecraft
- Command, Control and Communications Systems