Research On Aircraft Autonomous Navigation Based On Geomagnetic/celestial Navigation

Navigation system is an important part of an aircraft. Precise navigation parameters have a great significance to flight mission. Without any exchange of information with external systems, autonomous navigation relies only on the onboard sensors to complete the navigation task. With the development of the flight miss,autonomous navigation has gradually become the focus of space technology and an important research direction for aircraft control technology.Celestial navigation based on star sensor and infrared horizon sensor can be just applied to high orbit satellites. The precision of geomagnetic matching is restricted by the precision of standard geomagnetic model. Geomagnetic/Celestial autonomous navigation is presented to solve the problems above. This novel autonomous navigation method uses geomagnetic information obtained by magnetometer and starlight information obtained by star sensor to provide navigation information for aircrafts. Geomagnetic/Celestial autonomous navigation presented in this paper has great convergence, high navigation precision and good feasibility.Based on Geomagnetic/Celestial autonomous navigation method,the state space model is established. Instead of the orbital dynamics equation applied for high orbit air-crafts, common dynamics equation, which takes longitude, latitude, altitude and velocities of three axis in geographic coordinate system as state vector, is taken as state equation. And, in observation equation, the angle between geomagnetic intensity vector and starlight vector is taken as the observation vector.UKF method is designed for nonlinear Geomagnetic/Celestial autonomous navigation system. In order to avoid the problem of sensitivity to initial value of UKF,AUKF method is designed. The simulation results of Geomagnetic/Celestial navigation run by Matlab show that Geomagnetic/Celestial autonomous navigation presented in this paper has great convergence, high navigation precision and good feasibility so that it can provide precise navigation information, such as position and velocity for aircrafts. The simulation results under different simulation conditions also show that the increase of sensor precision and decrease of sampling period help to improve the navigation performance of Geomagnetic/Celestial autonomous navigation and AUKF method helps to inhibit the negative impact on navigation performancecaused by big initial value deviation when using UKF method.