Research On High-precision Repeat-groundtranck Orbit Design And Precise Orbit Maintenance Control Method

Repeat-groundtrack orbit is a kind of special orbit with the equal spacing of adjacent sub-satellite track at the same latitude circle,which repeat after a period of time.Repeat-groundtrack orbit can realize periodic and dynamic observation of specific ground targets,and has been widely used in space missions such as earth imaging observation and earth science exploration.In this paper,a high precision orbit design method and a precise orbit maintenance control method are proposed to satisfy the space mission requirements where the satellite orbit is required to have rigorous revisiting properties.Firstly,the orbit dynamic equation of near-earth satellites is established by analyzing the perturbation factors of near-earth space,and the method of Runge-Kutta-Fehlberg numerical integration is used to study the satellite orbit forecasting method with high precision.By comparing the orbit data forecasted by STK software,it is verified that the orbit forecast function module built in this paper can precisely forecast the satellite motion state.Secondly,based on the perturbation effect of the Earth's non-spherical gravity on the satellite orbit,an iterative method to design six orbit elements of Repeat-groundtrack orbits based on the J₂ perturbation term is studied,and then a single-objective optimization design method based on the high-order earth gravity field model to design Repeat-groundtrack orbits with rigorous revisiting properties is proposed.The simulation results show that the Repeat-groundtrack orbits with the revisiting accuracy of 1 m or less can be designed based on the orbit design method proposed in this paper,taking into account the perturbation effect of high-order earth gravity field.Finally,this paper studies the precise orbit maintenance control method based on the concept of"control tube"by analyzing the spatial error of satellite's actual orbit relative to the nominal orbit.Simulation results show that the orbit maintenance control method proposed in this paper can guarantee that the long-term orbit of the satellite is always in the"control tube",which indicates that the proposed method can guarantee the strict revisiting characteristics of long-term orbit.