Beam path adaptation system and method for free space optical communications systems

摘要

A system and method in the field of free space optical communications (FSOC) for overcoming atmospheric-induced spatial optical signal variations operates within each of two FSOC terminals that make up a bi-directional FSOC link, with each terminal providing the rapid adaptive beam path method over a much wider field of view than typically used for adaptive optical techniques. Each terminal uses a real-time adaptive beam-steering technique that continuously measures optical power and optical power gradients by the receiver optical detectors; this data is sent to a control system that automatically responds by re-aligning the optical system accordingly by maximizing the optical signal power measured by the optical power receiving detector.

主权项

1. A method for optical beam path tracking and adaptation in a free-space optical communications system comprising a telescope, an optical signal receiving device positioned in a focal plane of the telescope, a translation device configured to move the relative position of an optical signal peak spot and the optical signal receiving device in the focal plane, and an acquisition, pointing, and tracking (ATP) controller in communication with the translation device, the method comprising the steps of:
a. executing, using the translation device, an initial gradient scan in at least the X and Y directions to find an incoming optical signal; b. aligning, using the translation device, the optical receiving device with a first observed optical signal peak of the incoming optical signal as initially observed coarse tracking data; c. storing at the ATP controller a maximum peak location and maximum peak value correlated to an X-Y location in the focal plane and power of the first observed optical signal peak; and d. executing, at the translation device, an incremental X and Y stepping scan to determine if the optical signal changes in strength by a set value in the vicinity of the first observed optical signal peak, and if the optical signal power does not increase over the set value in at least two step increments from the first observed optical signal peak, continuing the scan in a different direction while maintaining the maximum peak location as the original signal peak location, but if the optical signal strength increases in a direction, then continuing scanning motion in that direction, and storing the increased optical signal strength and location as a new maximum peak location and maximum peak value as initially observed fine tracking data.