Demonstration and verification experiment in deep space optical communications

Abstract

In deep space optical communications, pointing, acquisition and tracking (PAT) system need to locate the position of the beacon, precisely. The way of employing the natural celestial body as the beacon come to draw attention, in contrast to regarding the laser as the beacon which has a series of problems of limited power, serious attenuation, high cost and difficult design realization. In this paper, the primary goal is to study the problem of precise positioning for the beacon by taking the natural celestial body as the beacon. Given the long distance, with small target and large uncertain region in deep space optical communications, the location of the beacon can be realized by the combination of rough and precise positioning based on the image feature of the beacon. Firstly, it performs the rough positioning according to the image characteristic information of the beacon’s edge, then in the uncertain region, the processing scope has been narrowed according the results of the rough positioning, finally the beacon is precisely located based on its minutiae feature by the way of feature point matching to achieve the position of the beacon. The impact due to the autorotation of celestial body on the image transform has been also discussed and analyzed with the mapping relationship of coordinate and geometric transform. The feasibility of the algorithm is verified by a long distance far-field Earth–Moon experiment. The design of system implementation on embedded hardware system can provide a reference for the real-time positioning system in deep space optical communications.