High Accuracy and Reliability Integrated Navigation Method for Long-Endurance Aircraft

A method of high accuracy and reliability integrated navigation for long-endurance aircraft is researched in this paper. Strapdown inertial navigation system (SINS), star sensor and global positioning system (GPS) are chosen as navigation equipments. In order to match the direction cosine matrix output of star sensor, a special matrix is constructed cleverly by outputs of SINS, and the difference between the above two matrixes is chosen as measurement of SINS/star sensor integrated navigation. Then Kalman filtering algorithm of SINS/star sensor integrated navigation is designed. At the same time, position and velocity outputs of SINS and GPS are taken to construct measurements of SINS/GPS integrated navigation, and its Kalman filtering algorithm is also designed. By designing the federated Kalman filter, local optimal estimations of system states from SINS/star sensor and SINS/GPS local filters are independently sent to the master filter, and global optimal estimations of system states are given by the master filter through global optimal fusion algorithm. Simulation results showed that, attitude accuracy of this integrated navigation method up to plusmn0.25, position accuracy up to plusmn2.4 m, and the reliability is satisfying when some navigation equipment is out of order.