Study On The Stability Of The Double Tracking System In Intersatellite Optical Communication

Intersatellite optical communications (IOC) will be an important element in the future satellite communication infrastructure, now it have been an actively studied field by many countries. The pointing, acquisition and tracking (PAT) technology used for the foundation and instauration of laser link is critical to an IOC system,. While the tracking system is used to keep the laser link exist, it is more important in the PAT system. There are two methods for the tracking system, including single tracking and double tracking, and the latter one adapt the system to the complex space environment better.First of all, the paper summarizes the research actuality and development of IOC technology in the world, also some typical PAT systems especially the tracking parts are analyzed. Then the tracking system in the IOC is introduced. After that, the main configuration and principle of IOC system, the azimuth angle model and the laser power received model were expounded, based on which the single tracking model used to analyses the double tracking method is consummated. The coupling equations are developed after analyzing the double tracking system. When developing the double tracking system model, the whole process is considered to be a multi-cycles process which contains two single tracking processes.A method based on the statistic theory is used while analyzing the stability of tracking system. On the foundation of the further research on the coupling equations, the mathematic expressions of the stability of tracking system and the conditional variance are explored. Then the steady variance and the initial value for steady variance which is related to the tracking time are developed. At last with the help of the numerical simulation, the effect of some parameters on the stability of double tracking system is analyzed.As a part of the research on the IOC, the needs of the simulation system of the IOC is consulted while developing the double tracking simulation system which is constructed based on the coupling equations of the double tracking system.The research of this paper not only provides the theory for the design of the double tracking system, but also supplies the double tracking simulation system for the whole simulation system of the IOC. Above all, the research has a great meaning to the PAT system.