An innovational transfer alignment method based on parameter identification UKF for airborne distributed POS

Airborne distributed Position and Orientation System (POS) depends on transfer alignment to obtain high accuracy motion parameters of sub-systems by using accurate motion information of main system, including position, velocity and attitude. Complicated aircraft flexure will decrease the accuracy of transfer alignment. Usually, the flexure angle is idealized as Markov process with fixed parameters, while these parameters are unknown and time-varying in real application. Accordingly, the accuracy of state model and statistic characters of noise will be incorrect, which consequently increases the error of transfer alignment. To solve the mentioned problem, this paper proposes a parameter identification method and then combines it with UKF. As a result, transfer alignment based on parameter identification UKF (PIUKF) is designed, and verified by simulations and static experiment. The results show that transfer alignment method based on PIUKF improves the accuracy of sub-systems compared with those based on UKF and strong tracking UKF.