The Error Source Analysis And Modeling For Solar Difference Autonomous Navigation

The solar Doppler difference navigation,as an effective and important navigation method,continues to attract people’s attention.Solar Doppler difference navigation and solar time difference of arrival navigation are two important navigation methods in solar autonomous navigation.The analysis of error sources is critical for the autonomous navigation system.In order to improve navigation accuracy,this article analyzes and models the error sources that cause navigation accuracy errors.In order to solve the above problems,a universal solar Doppler difference bias model and a three-dimensional model of the solar time difference of arrival measurement are established in this paper.The main contents include:(1)The solar rotation will cause solar Doppler difference bias,which will lead to the decline of velocity measurement accuracy of solar Doppler difference navigation system.Modeling compensation is an effective solution.The article based on the basic principle of solar Doppler difference navigation,the solar Doppler difference bias at any point on the solar surface is analyzed,and the solar Doppler difference bias model under arbitrary rotation axis is established.The theoretical analysis and simulation results prove that the solar Doppler difference bias model is closer to the actual situation than the traditional method.The factors such as the azimuth of the solar rotation axis changes,the distance between the spacecraft and Mars,and the spacecraft-Mars-Sun angle have a greater influence on the solar Doppler difference bias;(2)The time dispersion effect affects the accuracy of the solar time difference of arrival navigation.In this celestial autonomous navigation,Mars’ s moon is a reflecting celestial body,and its shape affects the solar time difference of arrival dispersion model.In this paper,we simplified the Mars’ s moons into ellipsoids or solid diamonds,and then established a solar time difference of arrival measurement model with non-spherical Mars’ s moons as reflecting celestial bodies.Finally,we analyzed the time dispersion caused by Mars’ s moons in theory.Theoretical analysis and experiments show that the point model error is 5.66 km,and the three-dimensional model error is within 70 m.So,the three-dimensional model of the solar time difference of arrival measurement model established in this paper is meaningful.In addition,the Sun-Mars’ s moons-spacecraft angle,solar flare,the three-axis length,and attitude of Mars’ s moons have a great effect on the dispersion profile,while the Mars’ s moons-to-spacecraft distance has a small effect.