Abstract:An angles-only tracking method for non-cooperative space targets in high earth orbits based on the extended Kalman filter(EKF) is proposed to solve the problem of tracking failure due to inadequacy of state equation during angles-only relative navigation. Firstly, a relative motion model with a non-cooperative target is established as well as its state equation and measurement equation accordingly. Then, appropriate perturbations are selected to add to the original Clohessy-Wiltshire equation, raising the accuracy of its state equation. Compared to the original method, this method raises the quality of the C-W equation, thus increasing its relative navigation accuracy. The evaluation of this method is assessed by applying different perturbations to target navigation simulations and comparing the errors between real motion trajectories and predicted ones. The final simulation results have witnessed a higher precision in navigation accuracy, meeting the requirements of relative navigation.