EFFECT OF PARTICULATES ON PERFORMANCE OF OPTICAL COMMUNICATION IN-SPACE AND AN ADAPTIVE METHOD TO MINIMIZE SUCH EFFECTS

Decreased signal-to-noise ratio and maximum bit rate as well as increa sed in error probability in optical digital communication are caused b y particulate light scatter in the atmosphere and in space. Two effect s on propagation of laser pulses are described: spatial widening of th e transmitted beam and attenuation of pulse radiant power. Based on th ese results a model for reliability of digital optical communication i n a particulate-scattering environment is presented. Examples for prac tical communication systems are given. An adaptive method to improve a nd in some cases to make possible communication is suggested. Comparis on and analysis of two models of communication systems for the particu late-scattering channel are presented: a transmitter with a high bit r ate and a receiver with an avalanche photodiode and a transmitter with a variable bit rate and a new model for an adaptive circuit in the re ceiver. An improvement of more than 7 orders of magnitude in error pro bability under certain conditions is possible with the new adaptive sy stem model.