A 6-DOF simulation has 6 degrees of freedom: three rotations and three translations. Since a

vehicle both translates and rotates through the air, two coordinate systems keep track of the

vehicle. The first is a known or fixed reference system, referred to here as a local-level coordinate system. The local-level system is a standard, right-hand, three-axis coordinate system with the x-y plane representing the horizontal ground plane the z-axis is positive down. -A 6-DOF simulation has 6 degrees of freedom: three rotations and three translations. Since a

vehicle both translates and rotates through the air, two coordinate systems keep track of the

vehicle. The first is a known or fixed reference system, referred to here as a local-level coordinate system. The local-level system is a standard, right-hand, three-axis coordinate system with the x-y plane representing the horizontal ground plane　the z-axis is positive down.