Low-density generator matrix code for correcting errors with a small optical transponder

Space optical communications is studied at National Institute of Information and Communications Technology, where the Small Optical TrAnsponder (SOTA) was developed and embarked on a 50-kg-class satellite. Atmospheric fluctuation is an issue to be solved in ground-to-satellite optical communication links. The SOTA has error-correcting functions using Reed-Solomon code and low-density generator matrix (LDGM) code to prevent the omission of data from signal fading owing to atmospheric fluctuations. In this paper, we present a demonstration that involves sending image data taken by an onboard camera with LDGM code via satellite-to-ground optical communication links. Our demonstration reveals how to correct the omission of data resulting from atmospheric turbulence and tracking errors.