The space catalog maintained by Naval Space Operations Center is a redundant backup to that used by NORAD, and becomes the primary one at times. Velocity accuracy normal to the NAVSPASUR fence is not measured with high accuracy, so several passes through the fence are required to determine the orbital elements of a newly discovered satellite. Once established, an element set can predict future fence crossings to within 0.2 seconds and a couple Hz doppler shift, so distinguishing a newly launched object from those already in the catalog is not difficult.