Application of symmetrized covariances in space confliction prediction Original Research Article

Space vehicle conflict prediction involving launch vehicles, space vehicles and electromagnetic radiation beams make use of position error covariance matrices of the respective objects. Such quantitative conflict predictions are needed to assess risk and help determine if a launch hold, space vehicle maneuver, or beam operational window closure is advisable. Computing the probability of conflict is greatly simplified by transforming respective positions, velocities and vehicle shapes to a coordinate frame in which the combined position error covariance is symmetric. Use of this symmetrized frame permits treatment of asymmetric vehicle shape, non-linear relative motion and time varying error covariance. Symmetrization also improves computation efficiency, which is especially beneficial in maneuver optimization to reduce conflict below a maneuver threshold, where large numbers of iterations are required.