1 American Institute of Aeronautics and Astronautics POSITION COVARIANCE VISUALIZATION

The expanding role of positional covariance data in modern spacecraft operations leads to a need for better understanding of the time evolution of covariance by mission planners and operators. It is common to see positional covariance information presented as uncertainties in the radial, cross-track and in-track directions. While such a time history does provide some information, it tends to obscure the true directionality of the uncertainty. A methodology for improving the understanding of position covariance based on 3D visualization is presented. The methodology utilizes sequential estimation to provide insight into the evolution of the covariance in the presence of measurements and to incorporate the effects of dynamic modeling uncertainties between measurements. Display of the covariance as a triaxial ellipsoid representing a desired probability level is discussed. Various methods for interpolating positional covariance are examined resulting in a recommendation of a technique based on an eigenvalueeigenvector decomposition of the covariance.