Trajectory estimation method of spinning projectile without velocity input

It is essential to obtain the position, velocity and attitude of a projectile for course correction, where the velocity of a spinning projectile is the hardest to obtain with merely a GPS (Global Positioning System) receiver. To realize trajectory correction without additional devices except a GPS receiver, a trajectory estimation method without external velocity input is studied. A modified point-mass model of the spinning projectile with fixed canards is established, and its real-time position and velocity is estimated by an extended Kalman filter with input of only position and rotational speed. A trajectory control technology is proposed as well and being verified by the hardware-in-the-loop simulations. The simulation results show that the proposed method can estimate the position and velocity of the trajectory properly and reduce the CEP (Circular Error Probable) of the projectile by about 100 m.