Research On Visible Light Scattering Characteristics Of Orbiting Satellites Based On Partial-component Modeling

The research on the scattering characteristics of space targets based on satellite targets provides important theoretical support for satellite detection,identification,stealth and the development of space-based target weapons.Moreover,it is also crucial for national defense security.The research mainly includes measurement and calculation on material BRDF,simulation on satellite orbit and attitude,calculation on satellite scattering intensity and background radiation.This paper derives scattering intensity algorithms in visible light(380-780 nm)for static satellites and orbiting satellites from the theoretical levels of scattering fundamentals,solar radiation and sun position,satellite orbits and attitudes.The scattering intensity distributions of static satellites and orbiting satellites based on partial-component modeling is calculated.The main content of this paper includes the following four aspects:First,the theoretical basis for the study of satellite scattering characteristics is introduced.The definition and calculation of the basic radiation quantity are introduced.The blackbody radiation law was introduced and the solar radiation illumination in visible light is calculated by this law.The definition of BRDF and the five-parameter statistical model is introduced.The calculation method of the sun position is introduced.Second,the satellite orbit and attitude system is analyzed.The Cartesain and Kepler Element describing the orbits of satellites are introduced,and their conversion formulas are deduced.The definition of the space coordinate system of satellites in orbit is introduced.The transformation matrixes of each coordinate system are derived,including the Earth-Centered Interial(ECI),the Earth-Centered Fixed(ECF),the orbital coordinate system,the satellite body coordinate system and the surface element coordinate system.The three methods for describing orbiting satellite attitude are introduced,including Euler Angles,Quaternions,and YPR.Using the definitions of each attitude,three kinds of attitude conversion formulas are deduced.Then,the visible light scattering characteristics for satellite in the target coordinate system is studied.The calculation process and judgment method for face element occlusion is deduced.The BRDF characteristics of the eight typical satellite cladding materials is studied based on the five-parameter model.The average BRDF of the material in visible light is calculated,and the results show that the OSR material has strong mirror reflection and its BRDF is the largest,and the scattering angle has a greater impact on the BRDF.Building satellite models based on sub-components which consists of seven components with an overall size of 835.89?7898.80?2323.85 mm,and 8832 triangular facets and 4594 points.The visible light scattering intensity of the satellite and its components is calculated which results indicate that the satellite has strong mirror reflection characteristics,and the satellite panel and body are the main sources of the overall scattering intensity of the satellite.When the incident direction is perpendicular to the panel,the satellite achieves the maximum scattering intensity.Finally,the visible light scattering characteristics of orbiting satellite is studied.The methods of visible judgment for target satellites,detection satellites and the sun are analyzed,in which the movement of the panel relative to other components is also considered.The basic operation of the satellite orbit and attitude of simulation in STK is introduced.Through STK,the orbit and attitude of the large elliptical orbiting satellite Molniya is simulated and the change of them are studied.Based on partial-component modeling and STK,the visible light scattering intensity of target satellites in the three orbits of low-Earth orbit,high elliptical orbit and geosynchronous orbit is studied.The influence of orbit,attitude and satellite materials on the visible light scattering intensity of orbiting satellite is analyzed.In the research process of this paper,in order to simplify the complexity,the satellite model is relatively simple,the target satellite model on different orbits is single,and the visibility of the results is poor.For these deficiencies,the satellite model can be further refined based on the characteristics of different orbits,and the calculation can be combined with the STK to realize the visualization of the calculation results.