Real‐time estimation of roll angle for trajectory correction projectile using radial magnetometers

An adaptive extend Kalman filter（EKF） is designed to estimate the roll angle for trajectory correction projectile only using radial magnetometers. By analysing the characteristics of the radial magnetometer output signal and the complex angular motion of the high-spin projectiles, the measurement equation is established. Two important measures, namely noise parameter adaptation and increasing system observation, are taken to improve the performance of the designed EKF. The novelty of this study is the proposed adaptive EKF has no requirements on the magnetometer measurement accuracy. That is the magnetometers used need not undergo a complicated calibration process. In addition, orthogonal difference method is introduced to adjust noise parameters. Finally, a series of numerical simulations and flight tests are carried out to verify the performance of the proposed method. The results show the designed adaptive EKF can effectively estimate the roll angle for the trajectory correction projectile and could be extended to practical engineering applications.