Research On The Simulation System Based On X-ray Pulsars Navigation

With the development of space technology,the range of space activities has gradually expanded to other planets in the solar system and other planets outside the solar system.At present,it is feasible to verify the feasibility of deep space navigation based on the American Deep Space Network,its role is limited by the vast spatial scale and cannot be competent for real-time navigation tasks in the future deep space exploration.X-ray pulsars navigation,it has become a very promising technology for deep space navigation with its high degree of independence,stability and high accuracy.Since our country carried out the research on X-ray pulsars navigation,it has been carried out on signal simulating,timing,determination of position and attitude,with the maturity of theory research,it is very necessary to build a mathematical simulation system to validate the correlation of theory method and technical accuracy and reliability.This paper focuses on the construction of the simulation system based on X-ray pulsars navigation,the main contents are:This paper introduces the space-time reference involved in X-ray pulsar based navigation,which is the basis for the establishment of mathematical models;The basic principles and mathematical models of timing,determination of position and attitude are given.According to the probability model of the time of photons arrival,the sequence of the time of photons arrival is generated by using mathematical method.X-ray detector,the key part of X-ray pulsars navigation system,its function model is introduced in detail,including the estimation of frequency and phase and the solution of ambiguity.After modeling each functional module,X-ray pulsars simulation system is built and the coupling relationship among the functional modules is analyzed,and the simulation experiment of function is completed.In the end,the hardware in the loop simulation system of the X-ray pulsars navigation is discussed.The construction of it is mainly discussed,and key components of the hardware in the loop simulation system of the X-ray generator and the detector are researched and summarized.The study on the coupling relationship of the X-ray pulsars navigation simulation system shows that the coupling relationship among the functional modules of the system is mainly based on the speed of the spacecraft,and its data structure is not directly coupled,so the study of the coupling relationship is concentrated on the influence of the speed of the spacecraft.The simulation experiments of timing module verify that the PLL designed in this paper can stably track the phase and lock the frequency of pulse signal.It can be used to correct the frequency of the spacecraft clock.The simulation experiments of navigation module prove the EKF and UKF can be used in X-ray pulsars navigation.And errors are the same as theoretical errors in order of magnitude,which verify the accuracy of the mathematical model;The verification of the accuracy and completeness of the data stream structure in system provides a theoretical support for the hardware in the loop simulation.