Nonlinear projectile attitude estimation with magnetometers and angular rate sensors

Abstract

Recent advances in low cost sensor technologies and nonlinear estimation techniques are applicable to the navigation of gun-launched projectiles. A method for attitude (i.e. angular orientation) estimation is presented that uses magnetometers aided by angular rate sensors. Nonlinear state estimators provide the filtering mechanisms to combine the measurements based on their levels of accuracy. Results are presented using the extended Kalman filter (EKF) and the unscented Kalman filter (UKF), and the UFK is shown to outperform the EKF. The proposed method is demonstrated to provide a full attitude solution while satisfying the stringent requirements of gun-launched projectiles.