Base class for prior on attitude Example:
Version of AttitudeFactor for Rot3
Version of AttitudeFactor for Pose3
Prior on position in a Cartesian frame. Possibilities include: ENU: East-North-Up navigation frame at some local origin NED: North-East-Down navigation frame at some local origin ECEF: Earth-centered Earth-fixed, origin at Earth's center See Farrell08book or e.g. http://www.dirsig.org/docs/new/coordinates.html