Position, velocity, and acceleration are called kinematics information. Rotational position analysis is the key to calculate kinematics of relatively moving rigid bodies. In this chapter, we review kinematics and show applied methods to calculate the relative kinematic information of rigid bodies. It is a necessary analysis to determine equations of motion of a vehicle expressed in body coordinate frame attached at the mass center of the vehicle. A vehicle will be treated as a moving rigid body in an inertia coordinate frame.