Research On Space-based Dual High-precision Ph Otoelectric System For Detecting Space Targets

With the development of space technology and changes in the world situation,the reconn aissance capabilities of on-orbit satellites towards space targets continue to improve,and the t rend towards space militarization will become one of the factors affecting global cooperation stability and balance.In order to ensure China’s optical-electronic detection of non-cooperativ e space targets,research on existing optical-electronic detection systems and further improve ments to existing methods are needed.The detection system is mainly divided into two types:ground-based detection systems and space-based detection systems.The former has been incr easingly perfected,while the latter is an area in which China is vigorously researching.Resear ch on space-based optical-electronic detection systems is advantageous for ensuring China’s s pace security and providing information support for space warning.This article focuses on the problem that when a single satellite detects a non-cooperative target,measurement errors in the measurement angle can lead to a decrease in positioning acc uracy and affect orbit determination.Research on a dual-star detection system is conducted,pr oposing a research plan for a space-based dual-star optical-electronic detection system for spa ce targets.The research includes the current situation of non-cooperative target detection,the measurement theory of optical angle instruments,the process of rendezvous measurement,du al-star detection simulation,and experimental studies.The specific contents are as follows:(1)The basic components and principles of optical-electronic detection equipment and th e errors that affect measurement accuracy during the detection process are studied.The imagi ng chain and signal-to-noise ratio model of the payload camera in the measurement process of the target are analyzed,and the factors that affect the camera’s detection performance,namely the characteristics of the space target and the camera,are further analyzed.(2)A space-based optical-electronic dual-star detection system for space targets is design ed,and the overall scheme is analyzed,including the definition of the time system and referen ce coordinate system.The characteristics of median filtering,mean filtering,and threshold seg mentation are compared,and the method of highlighting dim star point targets in the night sky background using threshold segmentation is analyzed.The effects of camera entrance pupil ar ea,signal-to-noise ratio threshold on the maximum detection distance,the relationship betwee n signal-to-noise ratio threshold and false alarm rate,and the effects of entrance pupil area an d signal-to-noise ratio threshold on the maximum detectable star magnitude are studied.(3)Based on the imaging requirements of the dual-star space-based detection system,var ious technical indicators and detectors are selected.The visible light band is selected,and a 1.5m aperture space-based telescope optical system is designed,which can achieve an imaging r esolution of 1m for targets at a distance of 500km.The transfer function of the system is close to the diffraction limit at the cutoff frequency.(4)Based on the optical-electronic detection equipment,namely the optical-electronic th eodolite,a simulation and verification model is established for the rendezvous measurement.A measurement model for the azimuth and elevation angles of the target is established,and th e errors of the two optical-electronic detection equipment are fused to improve the model accu racy.Based on this model,the azimuth angle,elevation angle,and target coordinates of the tar get point are measured using the theodolite,and the root mean square error of the target positi oning measurement by this method is simulated under the conditions of error satisfying a nor mal distribution,a target flight trajectory of-5000m<x_t<0,y_t=500m,z_t=500m,and the coordin ates of measurement station 1 and 2 are(600,0,-1200)and(800,0,-1200),respectively.The res ults show that the root mean square error of the measurement by this method is on average mo re than 40%higher than that of the reference literature,providing a technical means for impro ving the angular accuracy of the space-based optical-electronic detection system.