The Research On Methods Of Obtaining The High Precision Pointing Information In Space Optical Communications

Space optical communications (SOC) will be an important element in the future satellite communication infrastructure. An optical intersatellite communication system must be capable of high precision line of sight under disturbance in satellite environment for reliable communications. As a consequence, the acquisition, tracking and pointing (ATP) are critical and difficult issues in space optical communications. Therefore, it is indispensable to study the high precision ATP technology.Firstly, the basic concept of space optical communications and ATP, the definition of the pointing information (PI) and the three means for obtaining the pointing information, and the task and goal and structure about the paper were proposed.At chapter 2, the precision and the restriction for PI were discussed. By using the pointing error model, the conclusion was derived that the SOC links required the PI to be the sub-microradian. The basic limit for the position measuring was analyzed with the photoelectric signal model. The traditional target orientation methods were discussed and the ways for the correlation and the centroid of area were best, but they cannot fit the SOC.At chapter 3, the denoising methods for high precision centroid were discussed. It was found that the noises for far field spot belonged to the generalized Gaussian function by using wavelet method. Just so, the SUSAN filters, the wavelet filter for Bayesian estimate and for cross-valid were found to be the best denoising methods.At chapter 4, for the threshold chosen about the centroid of area, the Otsu is best in the three methods. The threshold, denoising way, and method to reduce the complexity for improved Otsu are presented, and the precision is 0.04 μrad.At chapter 5, the Two Spot Orientation (TSO) was discussed: After the picture was processed with SUSAN, the double-peak waves were gotten with the mean projection way, and the coordinates of the peak value were obtained by applying the...