Orbit-Determination And Precision Analysis Of Space Objects Based On Space-based Optical Surveillance

Space-based surveillance owns advantages of ground-based surveillance in monitoring coverage and real-time performance. And due to optical equipment's light weight, small size and low power consumption, optical measurement is used in space-base surveillance with great application prospects. This thesis focus on the orbit determination of space objects base on space-based surveillance, and proposes using the nonlinear relative dynamic model in orbit improvement and prediction.First of all, nonlinear relative dynamic model is established based on Lagrange equation, taking the Earth J2 perturbation into consideration. This dynamic model is used in orbit improvement and prediction. Comparison with the absolute dynamic model considering the same factor proves that the nonlinear relative dynamic model can be used to describe the relative emotion between the space object and space-based optical platform. Besides, error between nonlinear relative dynamic model and the reference model is calculated.Then the observing conditions are analyzed to simulated space-based optical measurement data correctly. The Earth's shelter and shade, the Earth's light condition, the Moon's light condition, the Sun's light condition and indirection condition are taking into consideration. Corresponding specific equations are give and simulations are taken to analyzed the affections of each observing condition on observations arc.As the observational data used here is simply optical angle information, Laplace method, which is simple and suit for observational data of one type, is used in initial orbit determination. Based on the improved Laplace method, perturbations are taken into consideration to better the initial orbit determination method's accuracy. And the initial value for iteration is obtained by Newton iteration accelerated by Aitken method, considering the Earth J2 perturbation. Besides, simulations are taken to analyze the ill-condition performance in initial orbit determination using short arc data.Principle of least square and Newton iteration are used to handle several observations arc data to improve the accuracy of initial orbit determination. The nonlinear relative dynamic model is used in orbit determination and prediction in the simulations of new space objects and objects cataloged, simulation results shows that the idea using nonlinear relative dynamic model in orbit determination and prediction based on space-based optical measurement data is practicable. At last, based on all the theories above, simulations are taken to analyze the orbit height of space-based optical platform and space object, observation arc length and sample period's impact on the orbit determination accuracy.