Attitude Estimation for Guided Projectiles Based on Magnetometers and Accelerometers

In order to accurately measure the attitude of guided projectile, a low cost strapdown navigation method using magnetic sensors and accelerometers is proposed. By establishing a simplified angular motion model, the state equation of nonlinear Kalman filter is obtained. According to the measurement principle and coordinate transformation of magnetic sensors and accelerometers, the measurement equation of nonlinear Kalman filter is derived. On this basis, in the simulation of the full trajectory, unscented Kalman filter (UKF) and mixed Kalman filter (MKF) are used to estimate the attitude angles. The results show that the estimation errors of the integrated system are reduced to 8.53%, 14.72% and 3.99% for angle of attack, sideslip angle and roll angle respectively, compared to the system with magnetic sensors only. Moreover, the MKF algorithm can reduce the amount of computation to 68.38% to meet the requirement of real-time performance.