Digitally modulated laser beam for bidirectional communication between satellites - has laser transmitter-receiver with digital modulation and second beacon aligning laser beam

摘要

The transmitter chain (1) has an input of digital words (2) with addition of a carrier frequency (9) and modulation (6) of the transmission laser (7). The laser beam (17) is transmitted through a mirror system (19,23) to a lens (20). The two way mirror (19) produces a reception laser beam (18) which is detected by a photoelectric cell (11), demodulated (12), the carrier frequency removed (13) to produce a digital word output (4). The laser operates at a wavelength of 0.8 microns. A second beacon laser beam (21) has a slightly diverging laser beam (22) which produces an opening cone allowing centring of the transmitting laser beam. USE/ADVANTAGE - E.g. for signal communication between orbiting and geostationary satellites, and relaying received data to central ground controller. Lightweight, low volume unit, allows satellite construction and launching costs to be reduced.