Probability density function based collision monitoring method within formation flight

In this paper a more precise collision monitoring method is proposed first, which takes the influences of the shape of satellite, predict time, relative covariance matrix and all kinds of perturbations into consideration. Then, because it is very difficult to predict the error of along track position, a conservative autonomous safety operational method based on the judgment of the collision probability in the projected X-Z plane is presented. Finally, the proposed collision monitoring algorithm is used to analyze the passive operational safety of Direct Satellite System (DSS), and a new formation geometry design method is proposed. By using this new design method the DSS can have good passive operational safety.