Precision location approach in deep-space optical communications

A traditional beacon location method is difficult to apply to a deep space optical communications link due to the high laser power required for long distances. The use of natural celestial bodies as beacon images can solve this problem. The correct location of the beacon is critical to establish and maintain an optical communications link. Therefore, in this paper we propose an approach to determine the location of a natural celestial beacon. To identify a beacon in an uncertain region, the phase correlation between the detected and reference images is applied. The influence of an image translation is eliminated through a Fourier transform, and the scaling and rotation are converted into the translation and solved using a log-polar transformation and phase correlation, respectively. The availability of a new approach is verified by the experiment. A field-programmable gate array embedded processing system is designed to realize the proposed algorithm. When the image noise is considered, the success probability of the algorithm can reach more than 96%. We believe this work is beneficial for deep space optical communications system design.