The point of closest approach to the surface of the specified position covariance ellipsoid surface along a defined direction. Position covariance must be available for a vehicle object to be considered a possible target for this option.

The grazing point is the point of closest approach to the surface of the specified position covariance ellipsoid surface along a defined direction. Position covariance must be available for a vehicle object to be considered a possible target for this option. The position covariance ellipsoid is computed based on the specification of either a 3D probability level (probability that the true position is inside the ellipsoid boundary) or a scale factor which is applied to the one sigma ellipsoid. To define a grazing point, start by selecting the target object about which the covariance ellipsoid is centered and specify the means for computing the position covariance ellipsoid. Next define a reference point which will serve as the starting location for the line along which the grazing point will be computed. Next define a direction to be used in conjunction with the displacement vector from the selected target object to the reference point to define a plane in which the line will lie. The grazing point will be computed starting with the line aligned with the specified direction, then rotating the line in the plane until the point of closest approach to the covariance ellipsoid surface occurs at the specified distance. A distance specification of zero indicates that the line will \"graze\" the covariance ellipsoid.