Improving Satellite Position and Velocity Estimation During Low-Thrust Maneuvers Using Multi-Bistatic Radar and Unscented Kalman Filter

Nowadays, tracking space objects presents a significant challenge due to the substantial increase in Resident Space Objects (RSOs) especially in Lower Earth Orbit (LEO) region. The anonymity of spacecraft maneuvers further complicates tracking and leads to inaccurate positioning of the spacecraft. This issue is mainly attributed to imperfections in the implemented data system and the dynamical model. As the number of RSOs in the orbital debris environment continues to grow, an accurate estimation of thrust becomes increasingly important for satellites during maneuvers and low-thrust transfer missions. Conventional methods of thrust estimation relies on postthrust changes in the orbit’s semi-major axis, which is not real-time. Ground-based sensors, such as radar, provide valuable real-time tracking information, but the costs associated with their implementation and use can be high. This study proposes a cost-effective solution to enhance the real-time accuracy of satellite tracking by using combinations of existing assets. Here specifically combinations of radar and existing radio telescopes is considered. The proposed solution utilizes an Unscented Kalman Filter (UKF) to estimate state vectors, demonstrating that combining multistatic radar and UKF can significantly improve spacecraft positioning and trajectory prediction. By incorporating tangential thrust into the multistatic radar scenario, the dynamic behavior of the satellite is explored, leading to more precise tracking and control of the satellite in its orbital path. For a measurement noise of 100 m standard deviation, the proposed system results in an error of less than two percent in all Keplerian parameters, except for eccentricity, which has an error of five percent. Root Mean Square Error (RMSE) analysis conducted for performance evaluation demonstrates significant improvement in position and velocity estimation, validating the proposed system’s effectiveness in enhancing space surveillance capabilities and ensuring better management of satellite movements for various purposes.