Research For The Spaceborne Laser Communication Terminal Tracking-pointing Turntable

With the continuous development of space technology,it is a trend to take use of small satellite platform building communication network.The mass of small satellite platform is 500-1000 kg,it requires that the mass is small of the communications terminal and has low power consumption.This article mainly study on the precision two-dimensional pointing mechanism on the background of the satellites laser communication link with small satellites platform.A LEO satellite orbit model is established.And through the simulation analysis of the dynamic characteristics of LEO-LEO communication link,obtained the time changing characteristics about distance,azimuth and elevation.And the he influence of on-board micro-vibration to the tracking system bandwidth is analyzed.The rationality criterion of the main design index of the tracking mechanism is given.The structure characteristics and application of the typical two-dimensional pointing mechanism are analyzed.Aiming at the strict quality and size limitation of the small satellite platform and the function requirement of the tracking mechanism,an antenna prepositioned periscope tracking mechanism structure based on the transmissive optical antenna is proposed.The single detector compound control APT system scheme and closed loop coarse tracking servo control schemes are adopted.According to the engineering requirement,the structure design,key device selection and modal analysis are carried out for the antenna prepositioned periscope tracking and pointing mechanism.The design of hardware and software for the servo control system of the ground test prototype are introduced.The coarse tracking algorithm is deduced and the mathematical model of the control system is established.The aiming performance of the tracking mechanism is studied,and the error terms including the light,machine and electric field is analyzed.The mathematical model of the aiming error is established by using the matrix optics method.The simulation results prove that the aiming performance of the tracking mechanism meet the design targets.