A Study On The Infrared Fine Spectral Radiation Characteristics Of Space Targets In Typical Environment

With the continuous development of modern aerospace technology,space targets play an increasingly important role.For the sake of national security,it is of great significance to protect and effectively identify space targets.Currently,the research of stealth and recognition is on the basis of the characteristics of the space target.The infrared radiation characteristics of the space target are important parameters in the target characteristic indexes.With the continuous improvement of the detector accuracy,it is possible to detect the background environmental radiation characteristics of the target,which has practical significance for the detailed spectral infrared radiation characteristics of the target in some typical environments.In this paper,the three-axis stabilized satellite and blunt-cone missile warheads are regarded as the main research targets,the steady-state infrared radiation characteristics of space targets are calculated under the typical background environment.Then the influence factors and degree of the environmental conditions are analyzed for infrared radiation characteristics of thin shell closed targets.Firstly,the motion characteristic model of the space target is constructed.The positions of the satellites in orbit and flying missiles at different times in the whole process are obtained.Meanwhile,the external normal vectors of the microelement surface are obtained.The micro-element method is used to calculate the solar radiation,earth radiation and earth reflected solar radiation received by each target surface,and the calculation of the out-of-orbit heat flow received by the target is realized.Through the heat balance equation,the steady-state temperature of each node surface of the target and the radiant exitance are calculated.Secondly,according to the MODIS temperature products of land,ocean,snow,sea ice and cloud top,the global temperature distribution and the underlying surface type distribution are constructed,which are used as input parameters of MODTRAN to calculate the earth radiation radiance and radiance of solar radiation reflected by the earth reaching the target.The detailed spectral infrared radiation characteristics of a three-axis stabilized satellite and blunt-cone missile warheads are simulated and analyzed.At the same time,the target temperature calculated by the traditional method is compared.The results show that the maximum absolute temperature deviation of the surface towards the earth of the satellite is 29K,the maximum absolute deviation of earth radiation radiance is32.02 W/m~2,the maximum absolute deviation of the radiance of solar radiation reflected by the earth is198.30W/m~2 the maximum deviation of the overall temperature of the missile is 15K.It is proved that environmental conditions,operating position,operating attitude have an effect on the infrared radiation characteristics of the target.Finally,using a controlled variable method,by changing the underlying surface temperature,type,atmospheric moisture content,aerosol type,the direction of the sun incidence,and the height above the ground,etc.,the integrated radiant exitance of a three-axis stable satellite is calculated at 3-5μm,8-14μm bands,and then the influence factors and degree are analyzed.Combined with specific calculation examples,the detection bands where the integrated radiant exitance of the target to the earth is more sensitive to environmental conditions are analyzed.The results show that,for satellites with low emissivity and low absorption rate,the temperature of the underlying surface has a greater impact on the target reflected radiation characteristics.The average albedo of the underlying surface has a greater impact on the target spontaneous radiation characteristics.Moisture content and aerosol visibility have little effect on infrared radiance in the infrared band.When the albedo of the underlying surface is large,the visibility of the aerosol has a certain effect on the radiance of the earth reflected solar radiation.The relationship between the incident direction of the sun and the position of the target has a significant effect on the solar radiation and the solar radiation reflected by the earth received by the target.