Study Of Phase Compensation Device Structure For Optical Sparse-aperture Imaging System

Optical sparse aperture imaging system is composed of several telescope subsystems arranged and spliced according to a certain sequence.Through coherent imaging method,the spatial resolution of the system is higher than that of any sub-aperture.In the process of coherent imaging,due to external factors and artificial assembly problems,beam synthesis errors will occur,which will affect the coherence of subsystems,and then have a significant impact on spatial resolution.In this paper,a phase compensation device based on optical delay line and fast reflector is designed to compensate the phase error.Firstly,the principle and method of phase compensation for sparse aperture imaging system are introduced.The structure characteristics of phase compensation device are analyzed.The performance and structure characteristics of existing beam phase compensation mirrors at home and abroad are discussed,and the main problems are analyzed.Then,several phase errors produced by sparse aperture imaging system and their effects on imaging resolution are analyzed.The method of phase compensation is studied,the design scheme of phase compensation device is given,and the main parameters of each component are analyzed and calculated.Secondly,the flexible support and mirror structure of phase compensation device are designed,which are mainly considered from three aspects: structural design,structural optimization and simulation analysis.The mechanical model of support is established and the expression of mechanical stiffness is deduced.The mechanical model is validated by finite element simulation.Through parameter optimization,Z-shaped support structure is designed to meet the performance requirements.Finally,the stress distribution of support under the circumferential and central radiation loads is analyzed by finite element method,and the support mode of central radiation type is selected.The mirror body design mainly carries on the overall design to the mirror body first,then carries on the topology optimization and the size optimization to the structure,determines the lightweight structure form of the back material removal,uses the finite element simulation method,carries on the analysis to the mirror body's surface accuracy under the bearing force and the temperature load condition,through the analysis of the surface curve,the mirror surface accuracy can satisfy the design request.Finally,the dynamic finite element simulation and error analysis of the whole compensator are carried out.The dynamic simulation mainly analyses the deformation and stress distribution of the whole compensator from three aspects: modal,random vibration and impact vibration.Under the external vibration conditions,the system has good stability.Then the error is quantitatively analyzed and calculated from following three aspects: structural design error,rotation center deviation error and load influence error.Under the influence of error,the compensation device meets the requirement of the index.