Narrow Laser Beam Transmission to a Geostationary Satellite

Experimental results are presented of narrow laser beam transmission from a ground station to the GMS-4 (Geostationary Meteorological Satellite-4) that has a visible channel detector. The experiment was carried out by using a highly accurate satellite optical tracking technique developed in our laboratory. By simultaniously tracking the GMS-4 based on the optical observation data prior to the laser transmission, a very narrow divergence laser beam with 95 μrad was successfuly transmitted to the satellite. Using the same technique, we succeeded in narrower divergence beam transmission with 35 μrad which is close to our destination for future space laser communication. A method of precise laser beam alignment using it's atmospheric backscattering image is also described.