Research On Technologies Of Space-Based Target Optical Detection

In recent years,space target surveillance system has received great attention,and the space-based surveillance system has become a popular research topic depend on its irreplaceable advantages.As the one of the key technologies of space-based surveillance system,space target detection technologies have obtained the extensive concern.The main task of space-based target detection is obtain the motion information of space target from the observation image.Optical observation mode is the mainstream observation approach of space-based surveillance system,it has a good capability to observe space target.So,the research on technologies of space-based target optical detection has a great value.Motivated by the significance of space-based target optical detection,this thesis presents an extensive investigation on the analysis of space target detection characteristic and space target detection technology.In the part of space target detection characteristic,the analysis of target detection characteristics is separated into three parts: space target observation characteristic,target imaging theory and CCD noise characteristic.Firstly,illumination condition and target observable condition are analyzed by computer simulation based on GEO satellite,then obtain the optical reflection characteristic of target on different time and different orbit.The target optical reflection characteristic provides the reference for observable and optimum observe time.Secondly,the imaging model is derived from the analysis of imaging theory.Thirdly,CCD noise characteristic is analyzed by investigation on different factors.In the part of space target detection,a detailed dissection is proposed on the process of target detection at first.Based on the analysis above,take the GEO satellite as target,the thesis proposed an algorithm: adjacent frame detection fusion to reduce the high false alarm in single frame detection.Besides,a star identification algorithm is presented to decrease the false identification.The experiment results show that the star identification algorithm has high accuracy rate,and the target detection algorithm can restrain the false alarm effectively,both of them have good stability for image or position noise and disturb stars.In the third part,due to the high risk,the exorbitant cost and long period of space flight lead to the difficulty in achieving real observation data,a space-based target imaging simulation system is designed and implemented for point space target based on the analysis of space-based target imaging process.The observation images of space-based target could be obtained via this simulation system at any time,on any orbit with three different structures.The simulation system can provide necessary data to verify the algorithms which proposed in second part.