The Use Of X-ray Pulsars Navigation For Constellation Autonomos Navigation

X-ray pulsar navigation is a new direction of the main navigation technology development in recent years. Its basic principle is using X-ray pulsar signal’s characteristics of high cycle stability and easy for observation, to acheive high precision autonomous navigation of spacecraft. X-ray pulsar relative navigation technology, by solving the pulsar signal’s time phase difference(TDOA) between two satellites, could eliminate the common errors, thus to effectively improve the precision of navigation.The paper uses Agent theory to study on the application of X-ray pulsar navigation in the constellation autonomous navigation. Firstly, the constellation is abstracted into a completely distributed structure of multi Agent system, and the Agent function model for pulsar navigation is established. The inter satellite visibility constraint is given, and the static and dynamic topology for the multi Agent system are designed. Study the constellation autonomous navigation algorithm based on pulsar’s TDOA information, and establish the simulation model of X-ray pulsar navigation for constellation, both of which are simulated and verified. Lastly, influences of the pulsar visibility, pulsar position error and the pulsar TOA measurement precision for pulsar navigation accuracy are analysed. The integrated navigation method of pulsars and inter-satellite pseudo range is put forward, which is based on inter-satellite links.Comparisons between static and dynamic topologys of the multi Agent system for pulsar navigation show that, in static topology, the satellite antenna does not need to switch between different satellites, so its algorithm is simple. But changes in antenna angle and angular velocity makes the antenna vulnerable. The static topology has less model measurements, so its orbit accuracy is low. In dynamic topology, the antenna switches between satellites, which makes the algorithm complex. But its significant advantages are, antenna angle and angular velocity has smaller changes, and the antenna is not easy to damage. The dynamic topology has multiple measurements, which brings high positioning accuracy.In the case of not depending on the ground station, according to X-ray pulsar’s TDOA information, satellite constellation autonomous navigation simulation is aided by the X-ray pulse in this paper. The result shows that, EKF filtering algorithm can reach the precision of 105 m in position and the precision of 0.116m/s in speed, and UKF algorithm can reach the accuracy of 44.56 m in position and 0.025m/s in speed. The UKF algorithm has longer operation time.Through the research of the influnce of pulsar measurements for pulsar navigation precision, explains the importance of the pulsar observation for the autonomous navigation. Through the integrated navigation of pulsar and inter-satellite pseudo range measurement, The simulation results show that, inter-satellite pseudo range measurement information increases the measurements, improves the X-ray pulsar relative navigation accuracy. By studying on the constellation autonomous navigation method based on inter-satellite links, demonstrates the feasibility and necessity of simplifing constellation autonomous navigation to inter-satellite relative position to determine the relative position.This paper improves the ability of independent operation of navigation constellation itself and the special case of survival ability, provides experience for research on the autonomous operation method of Beidou system.