A Precise Pointing Technique for Free Space Optical Networking

In free space optical communication networks, pointing, acquisition, and tracking (PAT) techniques are needed to establish and maintain optical links among the static or mobile nodes in the network. This paper describes a precise pointing technique to steer the local directional laser beam of an optical transceiver to a target optical transceiver at a remote transceiver node. The pointing technique utilizes Real-Time Kinematic GPS coordinates, local angular sensors, and a reference baseline, to retrieve accurate navigation information (roll, pitch, yaw) of the mobile or static platform that carries an optical transceiver. Through experiments using gimbal pointing stages, we have demonstrated "dead-reckoning" pointing accuracy in the milliradian range in our outdoor testbed.