Acquisition, Tracking, and Pointing in Optical Communication

A document in the form of lecture slides outlines a program of development of capabilities for acquisition of signals, tracking of signal sources, and pointing of transmitters and receivers in deep-space optical communications. Topics addressed on the first few slides include the benefits and challenges of optical communications and the historical and organizational background of continuing development efforts. Most of the remaining slides address selected technical aspects of acquisition, tracking and pointing (ATP) in various levels of detail; these aspects include basic principles of operation, beam-pointing requirements, sources of tracking and pointing errors, alternative approaches to tracking and pointing, concepts for the design and operation of ATP systems, and key technological developments that are necessary for attaining required levels of ATP performance. The last slide summarizes the major technical challenges; these include the difficulty of pointing the necessarily narrow transmitted laser beams, the need to suppress spacecraft vibrations in beam-pointing equipment, the need for bright beacons, and interference by scattered sunlight.