Aero-optics Imaging Deviation And Prediction With Different Line-of-sight Roll Angles

When the infrared guided aircraft flies at high altitude,a complex turbulent flow field is produced by the intense interaction between the incoming flow and the head of the aircraft.Because of the existence of this turbulent flow field,the image received by the optical imaging system of the aircraft is blurred,jittered,or even offset.This phenomenon is called aero optical effect.Aero optical effect is the bottleneck restricting the development of precision guided weapons.The research on the adverse effects of aero optical effect is of great significance to improve the accuracy of target recognition,help national defense construction and precision guidance.In this paper,the research background and significance of aero-optical effect in high-speed flow field are introduced firstly.The research history of aero-optical effects and experiments is reviewed,and the previous work is summarized.The theoretical basis of aerodynamic optical effect is described,the basic principle of fluid mechanics is studied,and the relationship between gas density and refractive index is deduced in detail.The concepts of aero-optical imaging deviation are introduced.Simulation part based on computational fluid dynamics(CFD),using the Solid Works 3 d modeling was carried out on the aircraft head,vehicle head meshing processing software ICEM completed before operation,then using the Fluent software to simulate aircraft flying at high speed optical hood near field distribution features,the density of view is given the definition of roll Angle and roll Angle of view and the view Angle,the relationship between imaging deviation part using the fourth order RungeKutta method of ray tracing,in reverse ray tracing is analyzed in the density distribution of light propagation path,The imaging deviation and the imaging deviation slope in the range of the line-of-sight roll Angle of 5°-85° are studied.The results show that with the increase of the line-of-sight roll Angle,the imaging deviation decreases and the decreasing speed accelerates.When the roll Angle of the small-angle line of sight changes,the change of imaging deviation is small,indicating that the imaging deviation is not sensitive to the change of the roll Angle of the small-angle line of sight.In pneumatic optical imaging deviation prediction,in view of the classic atomic search algorithm(ASO)easy to fall into local optimum and slow convergence speed of the faults,the introduction of the adaptive step length levy flight with gold sine the atomic search algorithm was improved,using four test function and comparison of three algorithms to test the performance of atomic search algorithm,the test results show that the IASO algorithm can overcome the shortcoming of easy to fall into local optimum and improve the convergence speed of the algorithm.The IASO-ELM model is applied to the aero-optical imaging deviation prediction.The aero-optical imaging deviation normalization part uses the fusion logarithmic transformation normalization,which can further improve the accuracy of the prediction.Based on the whale optimization algorithm(WOA),the convergence factor is adjusted nonlinearly and the inertial weight strategy is introduced to improve the algorithm.The IWOA is used to optimize the support vector regression(SVR)to predict the aerodynamic optical imaging deviation,which overcomes the shortcomings of the traditional SVR.The IWOA-SVR model constructed has high prediction accuracy and fast running speed,and provides a way to realize the rapid estimation of the aerodynamic optical imaging deviation.