A Proposal of Beaconless Ground to Satellite Laser Communication System by Using GPS Information

摘要

In a space laser communication between a ground station and a satellite, a beacon laser had been used in acquisition of the position of the ground station for the satellite in addition to a laser for communication. We propose a new approach in which the GPS information is used for initial acquisition of the position of ground station instead of the beacon laser. To implement this approach, the satellite's pointing error toward the ground station should be estimated when the information of GPS is used instead of using beacon laser. From the results, when the GPS information is used, we confirm that the satellite can point at the ground station by the same accuracy with the case of using beacon laser. Then, a laser divergence angle by considering the estimated error margin is calculated to irradiate the ground station sufficiently. Furthermore, the possibility of the beacon-less space laser communication system between ground and satellite is examined by calculating the beam wander effect and the point-ahead angle of light in laser downlink from the satellite to ground.