An Improved Hybrid Extended Kalman Filter Based Drag Coefficient Estimation for Projectiles

Abstract

An improved hybrid extended Kalman filter (IHEKF) is proposed for drag coefficient estimation from flight data of projectiles. In order to avoid the divergence or even instability in the implementation of HEKF caused by modeling errors and finite precision of digital microprocessors onboard the projectiles, fictitious process noise is added to the system model and covariance matrix is symmetrized at each time step. As a result, the robustness is improved. Finally, simulations are performed and the results demonstrate the effectiveness and superiority of the proposed method.