Research On Predict-pointing Communication Technology For High Earth Orbit Satellite Laser Communication Terminal

The research on pointing acquisition and tracking(PAT)technology has been carried out both at home and abroad.Great achievements have been achieved both in theoretical simulation and in orbit experiments.The ultimate goal of the PAT technique is to make the dynamic range of the signal light satisfy the ?rad.In this paper,high prediction accuracy of pointing angle under the condition that the acquisition process can be omitted directly to establish communication,put forward a forecast targeting communication technology,as a supplement to PAT's working conditions,is of great theoretical and practical significance for the future development of the technology.In the process of predict-pointing communication,the satellite can not be compensated in time by the spatial perturbation,and the perturbation of the space environment will affect the prediction accuracy of the point,thus affecting the communication performance of the system.Therefore,it is of great significance for satellite predict-pointing laser communication technology to analyze the satellite orbit perturbation and improve the prediction accuracy of the pointing angle.For the satellite to ground laser communication links,the atmospheric turbulence is also particularly obvious.It is necessary to further analyze the prediction accuracy and atmospheric turbulence combined with the angle of view.Aiming at the predict-pointing and communication process between the laser communication terminal of the high earth orbit satellite and the ground laser communication terminal,this paper has done some works:Firstly,this paper expounds the research background of PAT technology,and investigates the research status of satellite orbit theory,model and analysis method at home and abroad.The orbit perturbation model and attitude perturbation model for high earth orbit satellite are established.According to the terminal position vector,the transformation matrix between each coordinate system,the attitude orbit perturbation model and the pointing communication time in satellite laser communication,the model of satellite ground predict-pointing communication is established.This paper base on the attitude orbit perturbation model and the predict-pointing communication model,the effects of orbit perturbation,attitude perturbation and attitude orbit perturbation on the angle and angle error of pointing communication are simulated and analyzed.The reason of the difference of the pointing angle between GEO and IGSO is obtained.According to the orbit prediction algorithm and the attitude prediction algorithm,the model of satellite to ground prediction aiming communication process is put forward,and the prediction accuracy of the pointing angle of GEO and IGSO satellite to ground laser communication terminals is compared.In this paper,the angular error of satellite to ground laser link predict-pointing communication is defined,which is divided into fixed offset error and random fluctuation error.In this paper,the error rate formula is deduced from the atmospheric theory and the pointing error of the satellite to ground downlink,and the effect of the fixed-offset error on the bit error rate of GEO and IGSO laser communication link is simulated.Based on the beam drift,light intensity flicker and pointing communication error of the satellite uplink,the uplink bit error rate formula is rededuced.The influence of the fixed offset error of the ground to satellite uplink communication on the intensity flicker index and the communication error rate of the GEO and IGSO satellite laser communication links is simulated.