Abstract: For the space laser communication, the laser spot is usually distorted by the atmospheric turbulence and becomes the irregular shaped spot. To meet the challenge of insufficient angle measurement accuracy with four-quadrant detector (QD) for irregular light spot, a high precision deflection angle measurement method based on multi-source information fusion was proposed. The proposed method improves the measurement accuracy of the irregular spot deflection angle by integrating the data of QD and the image of charge coupled device (CCD), while maintaining high measurement resolution and high response speed of QD-based measurement method. Compared with the conventional QD algorithm, the results of both simulation and experiment show that, with the fusion algorithm, the root mean square error and the peak-to-peak measurement error are reduced by 55.56% and 42.98%, respectively.

Key words: space optical communication, beam deflection angle, irregular light spot, multi-source information fusion, fourquadrant detector (QD)