Tracking a ballistic missile in its reentry phase is one of the missile defence challenges as these reentry vehicles penetrate with large aerodynamic loads and sudden decelerations from exoatmospheric to endoatmospheric phase. With the advent of anti-ballistic missiles, the main goal of missile defence systems is to track the reentry vehicle to locate them precisely for allowing midair altitude interception. When these ballistic missiles suffer large aerodynamic loads and sudden decelerations the motion of the reentry vehicle is undoubtedly a nonlinear and forms a complex dynamic phenomenon. In this deceleration phase where the aerodynamic drag becomes predominant one parameter is used to characterize the deceleration: the ballistic coefficient. Therefore the knowledge and accurate estimation of this ballistic coefficient is used to relax the interceptor guidance, guidance and fire control purpose in stressing engagement geometries. With these insights, the paper deals with the implementation of Extended Kalman Filter (EKF) based on the linearization of the estimated state. Also this paper presents how EKF's are current efficient and classical solution to nonlinear filtering for ballistic coefficient estimation. This paper also deals with simulation of decelerating ballistic trajectory by accurately estimating the ballistic coefficient using EKF and this trajectory information is necessary to determine the impact point on the ground and accurate intercept point prediction.
Ballistic Missile, Aerodynamic Drag, Deceleration, Ballistic Coefficient and Extended Kalman Filter
