Research On Multi-source Combined Navigation Method And Application Of Mars Orbit Insert Segment For Mars Exploration Mission

Mars is the target celestial body with the largest number of human deep space exploration mission.Mars exploration includes flying,encircling,landing,patrolling,sampling returning,and et al.Encircling exploration is the most common form of omni-directional detection of Mars atmosphere and various elements of surface.In terms of encircling exploration,the probe requires to change its orbit from heliospheric orbit to Mars orbital orbit by orbital maneuver at the end of interplanetary cruise flight.The process of orbital transformation is called Mars capture.The only Mars capture opportunity is the key to the success of the mission.The characteristics and difficulties of Mars exploration lie in far flight distance,long mission time,large time delay of probe-earth communication and complex environment.Precise navigation data before and during braking and capture is an important guarantee for the success of Mars capture.Pinpoint accuracy and high reliability navigation is one of the key technologies to achieve safe capture.With full consideration of the engineering constraints of Mars exploration mission,the paper studies the navigation method of Mars capture section which is suitable for engineering application,which is of great significance to improve capture reliability and the rate of mission success.This paper combines Mars exploration project,Ministry of Science and Technology ‘973' Project ‘Basic Research on High Precision Autonomous Integrated Navigation Based on Celestial Angle and Velocity Measurement for Deep Space Exploration',aiming at the problem of Mars capture navigation under engineering constraints,carries out the research of multi-source integrated navigation technology and engineering application in Mars exploration capture phase.Firstly,establish dynamic theoretical model of Mars capture based on active and passive capture schemes.Study the dynamic model of Mars aerodynamic assistant capture and proposed the guidance strategy of Mars aerodynamic capture of rarefied atmosphere based on Mars aerodynamics capture method.Study the effects of various errors and synthetic errors on capture accuracy based on the error sources of capture process.Secondly,study the deep space network navigation supported by the ground deep space station and the autonomous navigation methods of spacecraft based on optical imaging navigation of Mars-Phobos-Deimos system.Analyze principles of ground radio navigation,optical imaging navigation based on Mars-Phobos-Deimos system,Mars navigation network,stellar spectral Doppler navigation and pulsar navigation.Establish the measurement model of each navigation method.The characteristics,error sources,application scope of various navigation methods and key technologies in engineering application of the above navigation methods are analyzed,and the influence of each error source on the navigation accuracy of Mars capture section is given.Thirdly,in terms of analysis of characteristics and accuracy of various autonomous navigation methods,the paper proposed a combination scheme of multiple navigation in Mars capture section for engineering application.Four integrated navigation methods,terrestrial radio and optical imaging integrated navigation,terrestrial radio and Mars navigation network integrated navigation,terrestrial radio and stellar spectral Doppler integrated navigation,terrestrial radio and pulsar integrated navigation,are studied.The observation models of each integrated navigation method are established,and the accuracy,convergence and applicable conditions of integrated navigation are analyzed.According to the characteristics of availability,real-time,continuity and accuracy change of ground radio navigation and autonomous navigation on spacecraft in the process of approaching Mars,the autonomous switching strategy of ground radio navigation and autonomous navigation on spacecraft in Mars capture phase is proposed to ensure the pinpoint accuracy and high reliability of Mars capture navigation.Finally,in terms of above theoretical work,a high-precision simulation system of Mars exploration navigation is established,which can simulate and analyze various integrated navigation method,simulate and verify the switching strategy of autonomous navigation between ground radio and spacecraft,and verify the accuracy of integrated navigation and the effectiveness of switching strategy.The simulation system built in this paper can meet the needs of verification and optimization of navigation scheme.