The attitude of the vehicle with respect to the vehicle's central body inertial coordinate system, expressed using YPR angles. YPR angles specify attitude using three rotations in sequence: a rotation about the X axis is called roll (R), a rotation about the Y axis is called pitch (P), and a rotation about the Z axis is called yaw (Y). Unlike Euler angles, the rotations are not made about axes defined by an earlier rotation: each rotation is made about the reference system's axes.