Research on Relative Motion of Approach to GEO satellite based on HEO

Abstract

For the problem of geostationary earth orbit (GEO) satellite's on-orbit servicing, a method is proposed by taking a photograph of GEO satellite through orbit maneuver vehicle (OMV) with CCD camera. Firstly, highly eccentric orbit (HEO) is designed for OMV. In order to avoid apogee's drift under J2 perturbation, strategy of orbit keeping is studied. Secondly, regarding GEO satellite as a reference spacecraft, C-W equations are used to depict OMV and GEO satellite's relative motion which lasts about 120seconds. The rationale of applying these equations is validated by making comparisons with the result of STK orbit propagator. To make C-W equations representing relative motion properly, GEO satellite is chosen as the reference spacecraft because geostationary earth orbit is circular. However, observation data which consists of relative distanceρ, Hi-Lo angleβand azimuth angleαare measured by measuring equipment which is installed on OMV in practical. The measuring variable should be transformed to virtual ones by GEO satellite in order to estimate GEO satellite's relative motion state versus OMV by filter. Then a kind of converting technique is presented. Finally, GEO satellite's relative motion state versus OMV is estimated by unscented Kalman filter (UKF). Numerical results indicate that high precision is achieved, and the state-estimation satisfies the requirement of precise trajectory propagate.