Pointing, acquisition, and tracking (PAT) technology for inter-satellite laser links

In this paper, we review pointing, acquisition and tracking (PAT) technology in inter-satellite laser links. Firstly, the structure of the PAT system is introduced, and the operating principle and the established procedure are also thoughtfully explained. Then, the optimization methods of the PAT technology are summarized following the three aspects: the building time for the link, the link stability and the beacon-free operation. In these methods, the complex communication environment as well as the device size and the data transmission rate are fully considered. Finally, we also list the latest laser terminal products, where the PAT technology implements on.