Research On Key Feature Inversion Method Of Space Objects Based On Photometric Data From Ground Observatory

With the development of astronautical technology,the types and number of space objects in space increase rapidly,so it is urgent to improve the ability of accurate identification and situational awareness of these targets.Ground-based optical observation system is an important means of monitoring and situational awareness of space objects,especially space objects on middle-high orbit.Due to the space object is far away from the ground-based observation station,observation data is basically point targets that only have brightness information.Moreover,the photometric signal is affected by many factors such as target orbit,attitude,material,illumination conditions,etc.,which also increases the difficulty of accurate inversion of key characteristics such as space target orbit,attitude and quality based on photometric signal.In addition,due to the influence of the noise observation model of the detection system and other factors,the key characteristic parameters inversion method based on photometric signal is applicable to the harsh conditions and the accuracy of the inversion results is not high,which is difficult to meet the needs of accurate identification and situational awareness of space objects.To solve the above problems,this paper establishes the observation model and motion model of the space object foundation,and combines with the idea of nonlinear filtering to conduct inversion method research on the key characteristics of the space target orbit,attitude and mass based on the foundation photometric signal,and carries out simulation experiment verification.The main contents of this paper are as follows:(1)The ground observation model and motion model of space objects are established.From the viewpoint of the photometric signal the formation mechanism of space object foundation,based on the radiation theory,the influence factors of optical signal to ground-based observations of space object are analyzed,considering the space target geometrical features and surface reflection features and the relative position of observation system and target attitude influence,combined with the space object surface reflection model,established the simulation model of space object photometric signal under ground observation condition,and based on the kinematic principle of space object,discrete time updating models of target orbit parameters and attitude parameters were established respectively,which provided model priori for the subsequent research on inversion methods of spatial object orbit,attitude and other characteristic parameters based on ground-based photometric signal(2)The key feature inversion method of space object based on the photometric data from ground observatory is studied.Due to the coupling effect of many factors,it is difficult to accurately retrieve the key characteristic parameters such as orbit,mass,attitude and so on,based on the theory of nonlinear filtering,the key feature inversion of space object is converted to the parameter estimation problem of nonlinear dynamic system.Based on the unscented Kalman filtering method,the feature of space object to be inverted is taken as the unknown state parameter of the system,when the space object geometry model is known,combined with the space target motion parameter updating model and the photometric signal observation model,the method of key feature inversion,such as space target orbit,mass and attitude,is constructed.(3)Simulation experiment verification.Combined with the simulation observation data,the inversion accuracy of this method was tested.According to the experimental results: when the space object geometry model is known,The inversion method in this paper can accurately invert the orbit parameters and mass of a space object,and on this basis,the parameters such as attitude and angular velocity can be accurately inverted for the space object with attitude change,when the target geometry model is uncertain,the right geometry model can be selected and the inversion of the orbit parameters and mass can be inverted.