Space-based Wide-area Optical Imaging Simulation Technology For LEO Space Debris

Facing the increasingly serious problem of LEO space debris,it is imperative to develop space-based optical detection platform.In order to meet the development and test requirements of information processing algorithm of space-based optical detection system,this paper studies the space-based wide-area optical imaging simulation technology for LEO space debris.The main research contents are divided into the following three parts:(1)Modeling of space-based optical imaging characteristics of space debris and stars.Firstly,the number of TLE orbital elements of space debris is analyzed by SGP4 model,and its motion orbit is calculated.At the same time,the star self-correction is carried out based on Tycho-2 catalog to establish its motion model.Then,the diffuse sphere model is used to approximate the optical characteristics of space debris,and the brightness model of stars is established based on the star catalog.Finally,the optical imaging characteristic model of the detection platform is established,and an adaptive modeling method of dispersion effect of optical system is proposed,which can adaptively set the window size of Gaussian dispersion function according to the target imaging gray level,and greatly improve the simulation speed.In addition,based on the working principle of CCD sensor,the bright star Smear effect is simulated and modeled.(2)Rapid analysis of space-based optical visibility for massive LEO debris.Firstly,the earth occlusion constraint,earth shadow constraint,Sun and Moon interference constraint,detection field of view constraint and detection magnitude constraint models affecting the visibility of space debris are established;Secondly,aiming at the problems of large number of LEO space debris and slow solution of visibility analysis,based on the quantitative analysis of the computational complexity of the five types of constraint models and the screening ability of debris visible window,a quantitative evaluation index to measure the efficiency of solving debris visibility under each constraint condition is defined,and the optimal solution order of the five types of constraint models can be determined.Simulation results show that compared with the traditional serial algorithm,the visibility solution speed of massive LEO debris is greatly improved.(3)Image simulation of space-based wide-area optical detection of space debris.Firstly,a debris and star image simulation method with adaptive exposure time is proposed.The imaging trajectory of the observed target in the exposure time is calculated based on the number of debris orbits or the star catalog.Based on this,the imaging gray of the target on the passing pixel points is calculated.After Gaussian dispersion,the target simulation image can be obtained,and the realistic simulation of debris and star tailing under long exposure time is realized.Secondly,aiming at the phenomenon of stray light interfering with imaging in the process of space-based optical detection,the judgment models of earth-atmosphere radiation and moonlight interference imaging are established,and the imaging simulation of earth-atmosphere radiation and moonlight is realized by using micro element method and extended interception method respectively.A large number of simulation experiments show the effectiveness and rapidity of the proposed method.