In-Flight Alignment Algorithm based on Non-Symmetric Unscented Transformation

This paper describes in-flight alignment algorithm using non-symmetric unscented Kalman filter (NSUKF) for an SDINS aided by GPS system. To overcome the EKF limitation, the unscented transformation (UT) was developed as a method to propagate mean and covariance information through nonlinear transformation. However, the original UT has both the local sampling problem and the global sampling problem. To solve these problems, we propose the non-symmetric unscented transformation (NSUT) and apply the NSUKF based on the NSUT to the IFA with the large heading error. With a low cost MEMS IMU, the simulations are carried out at S-type trajectory for analyzing the performance of the proposed method