Research On The Pointing Error Of Telescope Mount In Slr System

Satellite Laser Ranging(SLR), which appeared in the mid 1960's, is one of high precise space techniques. After almost forty years'development, the single-shot ranging accuracy has reached sub-centimeter level and it has been applied in many scientific fields. Up to now the single-shot ranging accuracy at Shanghai Observatory reached 10~12mm. Based on the experiences in night-time observations for a decade and a great deal of improvement of equipments and techniques, the Shanghai SLR system had the routine daylight tracking capability and became the first daylight tracking system in China. However, daylight tracking is more difficult than that in night-time and its probability of success is lower than night-time. The pointing accuracy of telescope mount is one of the most important factors which limit tracking capability in the daylight. To improve the pointing accuracy of the telescope mount and the capability of daylight tracking, it is necessary to do more study on the error of telescope axes. The present thesis analyses many kinds of factors that cause the pointing error of telescope mount, and discusses the method for correcting the pointing error by setting up telescope mount model in detail. We figure out the telescope mount parameters by observing stars with CCD, and establish a measurement system, including CCD and image acquisition card to collect stars'image data, time and frequency system (made up of high accuracy counter, the GPS second signal and 10MHz frequency standard), the observing software in VC++6.0 for collecting and processing star image and the image processing software programmed with MATLAB. Considering the telescope's tracking error, we adopted the method of static pointing in the experiment. 9″and 5″pointing precision with the basic parameters model and the spherical harmonic model was obtained respectively. In the thesis we also compared the basic parameters model with spherical harmonic model and come to the conclusion that the basic parameters model is more stable and all parameters have their physical meanings, and its internal fitting precision is consistent with its external fitting. Internal fitting precision of the spherical harmonic model is higher than one of the basic parameters, however it is not stable enough and the coefficients vary dramatically because of the high correlation among the parameters. So it is considered that the basic parameters model is more suitable to the SLR telescope.