Onboard observer-enhanced filter in handling orbital elements estimation of non-cooperative target.

The purpose of this paper is to develop an effective method for onboard absolute orbital elements estimation of the non-cooperative target, which may beneficial to collision avoidance. The proposed estimator consists of two parts: the target acceleration observer and the orbital elements filter, where the observer generates partial input for the filter. For the estimator, the data source comes from the orbit determination information of the obstacle-avoidance-satellite and the relative measurement information of the non-cooperative target. These data are fed into an observer to estimate the maneuvering acceleration of the target. Then, the square root cubature adaptive H ∞ information filter (SCAHIF) for target-orbital-elements estimation under the complicated noise condition is designed, which is driven by the observer outputs and the target data source. The performance of the overall "observer-enhanced SCAHIF" (OSCAHIF) is evaluated through three scenarios where the target is under zero maneuvering thrust, constant maneuvering thrust, and time-varying maneuvering thrust. Test results indicate that the proposed OSCAHIF provides a feasible solution to real-time absolute orbital elements estimation of the non-cooperative target with the presence of time-variant mixed Gaussian white noise. • OSCAHIF is proposed for orbit element and thrust estimation of noncooperative target. • An observer is developed for maneuver acceleration estimation. • The adaptive H-infinity method is introduced to improve the robustness. • The observer, square root cubature IF, and adaptive H-infinity method forms OSCAHIF. [ABSTRACT FROM AUTHOR]