Research On Line-of-sight Pointing And Prediction Technology For Electro-optical Telescope

In the fields of optical communication,astronomical observation and shooting range photoelectric measurement,the electro-optical telescope(electro-optical tracking system)is needed to capture and track the target quickly and accurately.Compared with radar detection mode,electro-optical tracking system has the advantages of long detection distance,high measurement accuracy,low operation cost and good concealment of equipment.It is an important target monitoring mode.Due to the low signal-to-noise ratio of the target in actual observation,the field of view of the target detector is generally small,coupled with the disturbance of ground shadow,atmospheric disturbance and other factors,the target cannot be effectively extracted in the field of view,thus causing the closed-loop tracking method based on miss distance cannot run smoothly and continuously.The tracking equation should be established according to the existing observation data to predict the position of the target under abnormal observation conditions to guide the electro-optical tracking system and realize recapture the target.The high precision direction accuracy is the basis of high precision observation,and also the precondition of high precision prediction and tracking.In this paper,a 1m-aperture alt-az electro-optical tracking system is used to study the theory and application of pointing error correction technology and target prediction tracking technology,and a series of innovative achievements have been achieved.The error of the electro-optical tracking system in the process of processing and assembling is the main factor affecting the pointing accuracy.The analysis and correction of the pointing error source is an important means to improve the pointing accuracy.Based on the geometric error analysis of the electro-optical tracking system,a frame model with clear physical meaning is established by combining the multi-body dynamics theory and error transfer principle.At the same time,aiming at the non-linear errors that cannot be corrected by the frame model,a directional error correction model based on ALLAN variance is proposed,which effectively improves the pointing accuracy of the electro-optical tracking system.Based on the analysis of the motion characteristics of space debris,the least squares polynomial fitting model is selected as the kinematics prediction model.The random sampling consistency algorithm is introduced into the outlier processing of the observed data.The loss function is improved according to the distribution characteristics of the observed data,and a robust least square method is proposed based on the polynomial fitting model.In order to solve the problem that the model error varies continuously with the environment and other nonlinear factors that cannot be expressed accurately with a small number of parameters,a model parameter estimation algorithm based on semi-parametric regression is proposed.The non-parametric is introduced to represent the model error that varies continuously with time,which enhances the model's ability to suppress the nonlinear interference.Based on the analysis of space debris dynamics model,an orbit determination and prediction algorithm based on adaptive UKF is proposed.Aiming at the problem that the horizontal electro-optical tracking system cannot obtain absolute radial measurement information,the orbital elements are used as intermediate variables to output the azimuth and elevation of the target,which is sufficient for the observation data.Aiming at the problem that traditional UKF needs to know the prior statistical characteristics of noise,an adaptive UKF algorithm based on time-varying noise estimator is proposed,which can estimate the statistical characteristics of time-varying noise on-line without the prior information of noise,thus improving the stability and robustness of the algorithm.In this paper,the theory and application of high precision pointing error correction technology and target prediction and tracking technology of electro-optical tracking system are deeply studied,and tested in field test,which can provide useful reference for workers in related fields.