Research On Information Fusion In Navigation System Of Reusable Launch Vehicle

Reusable launch vehicle can reduce the cost of entering the space and serve for the strategic aims in aerospace. During the flying time of the RLV, the significant of navigation system is self-evident. The accuracy of navigation system can be improved by initial alignment and navigation information fusion in-orbit. The bias error of accelerator and gyroscope can also be estimated at the same time to satisfy the demand of error demarcation.This dissertation focus on the high-precision and high-reliable navigation system during long duration. The navigation precision and mission-performing capability of the RLV can be improved through the theoretical analysis and simulation of initial alignment and in-orbit navigation information fusion.First, force analysis about the RLV during launch and in-orbit has been taken to establish the dynamic and kinematic model of the RLV. After that, modeling the environment disturbance before launch, especially the wind.What comes next is the research on the navigation method and error model under the assumption of minor angle and linearization. Through simulation and analysis, the efficient of these models have been proved.Based on the research above, analyzing the workflow of inertial initial alignment, researching on the analytic coarse alignment by geographic information and extractive alignment by Kalman filter. A method about initial alignment and evaluation of the precision of alignment has been proposed.At last, observation formulation of GNSS and CNS has been given by analyzing the error feature and error model of GNSS and CNS. Designing the information fusion filter of INS/GNSS/CNS, and some simulation has been taken to testify the proposed theory and method.